Mexican competition: now from the...
 'Solar fire' and other hot tomato...
 Tomato yellow leaf curl virus...
 What's up with all these white...
 Tomato disease update
 Tomato disease update
 Weed hosts, field distribution,...
 Innovative approaches for soil...
 VIF research and its role in methyl...
 Tomato varieties for Florida
 Water management for tomato
 Fertilizer and nutrient management...
 Weed control in tomato
 Nematicides registered for use...

Title: Florida Tomato Institute proceedings
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00089451/00002
 Material Information
Title: Florida Tomato Institute proceedings 2003
Series Title: Florida Tomato Institute proceedings
Physical Description: Serial
Language: English
Creator: Gulf Coast Research and Education Center. Institute of Food and Agricultural Sciences, University of Florida
Publisher: Gulf Coast Research and Education Center. Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Wimauma, Fla.
Publication Date: 2003
 Record Information
Bibliographic ID: UF00089451
Volume ID: VID00002
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.


This item has the following downloads:

TOMATO%202003 ( PDF )

Table of Contents
        Page 1
    Mexican competition: now from the greenhouse
        Page 2
        Page 3
    'Solar fire' and other hot tomato breeding topics
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
    Tomato yellow leaf curl virus revisited
        Page 9
        Page 10
        Page 11
    What's up with all these whiteflies?
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
    Tomato disease update
        Page 20
        Page 21
    Tomato disease update
        Page 22
    Weed hosts, field distribution, and sampling strategies for root-knot nematode
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
    Innovative approaches for soil fumigation
        Page 34
        Page 35
        Page 36
        Page 37
    VIF research and its role in methyl bromide phaseout and update on long term methyl bromide alternatives study
        Page 38
        Page 39
        Page 40
        Page 41
    Tomato varieties for Florida
        Page 42
        Page 43
        Page 44
    Water management for tomato
        Page 45
        Page 46
        Page 47
        Page 48
    Fertilizer and nutrient management for tomato
        Page 49
        Page 50
        Page 51
        Page 52
        Page 53
        Page 54
    Weed control in tomato
        Page 55
        Page 56
        Page 57
        Page 58
        Page 59
        Page 60
        Page 61
        Page 62
        Page 63
        Page 64
        Page 65
        Page 66
        Page 67
    Nematicides registered for use in Florida tomatoes
        Page 68
Full Text

PRO 520

2003 Tomato Institute Program
Ritz Carlton Naples, Florida September 3, 2003

Moderator: Mary Lamberts, Miami/Dade County Extension Service, Homestead

9:00 Welcome & Opening Remarks Larry Arrington, Associate Dean for Extension, UF/IFAS, Gainesville

9:15 The "State of the Florida Tomato" Address Reggie Brown, Florida Tomato Committee, Orlando

9:30 Mexican Competition: Now from the Greenhouse Dan Cantliffe, Horticultural Sciences Department,
Gainesville, pg. 2

9:50 Methyl Bromide CUE: Where Do We Stand? Mike Aerts, Florida Fruit & Vegetable Association, Orlando

10:10 "Solar Fire" and Other Hot Tomato Variety Topics Jay Scott, GCREC, Bradenton, pg. 4

10:30 Tomato Yellow Leaf Curl Virus Revisited Jane Polston, Plant Pathology Department, Gainesville, pg. 9

10:50 What's Up With All These Whiteflies? Dave Schuster, GCREC, Bradenton, pg. 12

11:20 Lunch

Moderator: Alicia Whidden, Hillsborough County Extension Service, Seffner

1:00 New Product Updates Industry Representatives

2:15 Tomato Disease Update Pam Roberts, SWFREC, Immokalee, pg. 20

2:35 Tomato Herbicides: What We Have Gained, What We Have Lost and Possible Future Labels Bill Stall,
Horticultural Sciences Department, Gainesville, pg. 22

2:55 Weed Hosts, Field Distributions and Sampling Strategies for Root Knot Nematode Joe Noling, CREC,
Lake Alfred, pg. 23

3:15 Innovative Approaches for Soil Fumigation Dan Chellemi, USDA-ARS, Ft. Pierce, pg. 34

3:35 VIF Research and Role in Methyl Bromide Phaseout: Update on Long Term Methyl Bromide
Alternatives Study Jim Gilreath, GCREC, Bradenton, pg. 38

4:00 Adjourn

Control Guides:
Tomato Varieties for Florida Stephen M. Olson, UF, NFREC, Quincy; and Donald N. Maynard, UF, GCREC, Bradenton, pg. 42
Water Management for Tomato Eric H. Simonne, Horticultural Sciences Department, UF, Gainesville, pg. 45
Fertilizer and Nutrient Management for Tomato Eric H. Simonne, Horticultural Sciences Department, UF, Gainesville, pg. 49
Weed Control in Tomato William H. Stall, Horticultural Sciences Department, UF, Gainesville; James P. Gilreath, UF, GCREC,
Bradenton, pg. 56
Chemical Disease Management for Tomato Tom Kucharek, Plant Pathology Department, UF, Gainesville, pg. 59
Selected Insecticides Approved for Use on Insects Attacking Tomatoes S. E. Webb, Entomology & Nematology Department,
UF, Gainesville, pg. 62
Nematicides Registered for Use in Florida Tomatoes J. W. Noling, UF, CREC, Lake Alfred, pg. 68

Mexican Competition: Now from the

Dan Cantliffel and John Vansickle2
1Horticultural Sciences Dept., UF Gainesville, 2Food and
Resource Economics Dept., UF Gainesville

Commercial greenhouse production of horticultural crops in Mexico
started in the 1950s. Initially local growers produced flowers in wood-
type structures covered with plastic. It was not until the 1980s, however,
that greenhouse-type structures were used in vegetable production. By
today's standards, these structures were semi-rustic. In the 1990s, larger,
more modern greenhouse structures began to appear in various places in
Mexico. More vegetables started to be produced, primarily destined to
export market, and thus at that time investment capital became available
as well as interests from various groups from countries including Israel,
Holland, and Spain began to both sell and operate greenhouses for veg-
etable production in Mexico.
Presently there is in excess of 5000 acres of greenhouse production
in Mexico. Estimates place about half of this production in vegetables
and the other half in floral production.
Growers in Mexico have turned to greenhouse production of veg-
etables in order to provide a controlled environment to improve product
quality. Mexican greenhouse producers have been attempting to develop
vegetable brands that are accepted in the marketplace by wholesalers and
other buyers. They hope to improve their image on product quality and
food safety as well as maintain stricter control of water quality.
It is estimated that there are approximately 12 major providers of
vegetable greenhouse products to the United States from Mexico (Lopez
and Shwedel, 2001). These producers are primarily targeting the winter
market when the prices are highest. The use of greenhouse production
helps the Mexican producers offset certain problems with production as
it relates to weather, both rain and cold temperatures, and thus they are
able to better adjust the timing for market delivery.
Presently there are various reasons for Mexican producers to devel-
op a greenhouse industry for vegetables. These include 1) the need to
reduce the impacts from variations in climatic conditions on produce
quality. 2) The opening of the Mexican economy, bringing with it access
to J,.itt -cLr types of technology, i.e. people are willing to invest in
Mexico. 3) The search for solutions to d.ittcicL! pi.. Ilc 1, that affect open
field production, for instance, various diseases, insects, weeds, etc. 4) An
increase in demand by consumers for better and safer products, especial-
ly for export markets where food safety issues, including the border qual-
ity, have the potential to become major trade issues.
Mexican vegetable greenhouse production has been highly devel-
oped in five states including Baja California which is 9.5% of the pro-
duction, Baja California Sur 13.5%, Sonora 6.9%, Sinaloa 26.3%, and
Jalisco 27.4% (Lopez and Shwedel, 2001). It is estimated that total value
for vegetable production from Mexican greenhouses is in excess of $300
million today. The major vegetable crops produced are tomatoes (60% of
the total greenhouse area), cucumbers (20%), and peppers (10%). Of the
tomatoes, the main varieties are vine-ripe large rounds, cherry tomatoes,
Roma tomatoes, and also a group called greenhouse tomatoes.
Twelve years ago, in 1991, there were only 125 acres of vegetables
being produced in greenhouses in Mexico. Because of NAFTA and the
enhanced access to the U.S. market, interest in greenhouse production has
grown dramatically over this period. Further, as the Mexican economy
improves and the peso strengthens, the greenhouse industry has expanded
greatly in the last two or three years. Presently there is in excess of 2500
to 3000 acres of greenhouses being dedicated to vegetable production.
Although much of the production is in the five Mexican states previously
mentioned, there are 15 states in Mexico with greenhouse vegetable pro-
duction. About 84% of the total production, however, is in those five

The U.S. is by far the most important market for Mexican green-
house vegetable producers. Over 92% of the greenhouse production for
export goes to the U.S. The rest goes to Canada and as far away as to
Europe and the E.U. (Lopez and Shwedel, 2001).
In 2000, total imported tomato value into the U.S. was approxi-
mately $147 million, or 95,000 tons of fresh market tomatoes. Of those
values, $78 million of tomatoes produced in the greenhouse were being
imported from Canada, while $36 million worth of tomatoes were being
imported from Mexico. In contrast to only one year previous, 1999, the
value had risen over $100 million because of import of greenhouse toma-
toes into the U.S. which in 1999 was somewhat under $44 million at
28,000 tons. Mexican producers had only $4.2 million of that market
share. Thus, in the one-year period, importation of tomatoes from
Mexican greenhouses increased in value from $4.2 to $36.1 million.
Subsequent to that, importation of tomatoes from Mexican greenhouses
has increased. Several large field producers of Mexican tomatoes have
converted to partial or total production coming from greenhouses over
the past 4-5 years. Dutch and Canadian greenhouse tomato prices are still
higher than those tomatoes coming from Mexico. The lower prices are
somehow reflected in transportation cost dit t-icir I to major markets,
cheaper labor costs and newness of the Mexican greenhouse industry in
the marketplace. As the greenhouse industry matures, it is bound to
expand and product prices are bound to improve.
With regard to structures, plastic greenhouses cover about 95% of
the total area of the greenhouse production and only 5% or less of the area
is covered with glass. The primary reason is the price J i tc i c r II and the
fact that in many regions in Mexico, glass is not needed. The plastic film
used is PVC (polyvinilic chloride) and most of the greenhouses are high-
roofed generally 4-5 meters from floor to the top beam. A large number
of the greenhouses are locally produced in Mexico. However, there are
also a large number of greenhouses from Israel, Canada, the Netherlands,
Spain, France, and the U.S. Mexican greenhouses are of somewhat less
quality, but also cost less than imported houses. Israeli greenhouse man-
ufacturers will sometimes help with funding of greenhouse construction,
while greenhouse manufacturers from Spain will setup greenhouses for
certain growers free of cost for a certain percentage of return on the crop
that will be produced from the greenhouse. It is estimated that the basic
structure for 2.5 acres is $165,000 USD for construction (Lopez and
Shwedel, 2001). This price includes all the metal and plastic, but does not
include any mechanical features, or the irrigation. Many times local labor
is used for construction, and whenever lesser materials are used con-
struction prices can be somewhat lowered as much as 50% from that cost.
In Mexico local banks will loan capital for investments for periods
of only up to five years. The credit market has relatively high borrowing
costs in local currency, thus most producers are forced to go with less
expensive plastic style greenhouses. In many areas of Mexico, especially
in Sinaloa, which is the second largest vegetable producing state, tem-
peratures in the winter time can fall either near or below freezing. Most
greenhouses were constructed without heating systems, however new
greenhouses are being constructed with either hot water tubing or gas
generated space heaters. The heaters are generally manually operated,
and thus producers can be assured that if temperatures go to or below
freezing, they will have produce to sell in the winter time in the U.S.
In summary, most areas of Mexico provide a perfect environment
for greenhouse vegetable production. Good day length and strong light
intensity during the winter months are prime factors in developing a
greenhouse industry in this region of the world. Technology has been
available from outside sources and especially cost effective in construc-
tion are the Israeli type high-roof passive ventilated greenhouses, and
more recently into Spanish new-style greenhouses. Production of crops
from the greenhouse gives production advantages, such as improved
scale of efficiencies from a variety of J. tc i c 1i r systems and the ability to
market a premium product. Some of the constraints are the fact that in
much of the production areas there is a long distance to the market place,

especially in places in Baja or Sinaloa or Jalisco, in many cases a 36-hour
ride or longer to southern California or southern Arizona. Further, mate-
rial costs are similar to the U.S. or higher, but labor in general is consid-
erably lower. Another concern, especially in the Baja, is water, both quan-
tity and quality.
Greenhouse production is in fact becoming more common and more
popular in Mexico. Medium and large producers are beginning to devel-
op strong greenhouse production systems and take advantage of existing
marketing outlets. With access to North America, especially the U.S.,
through NAFTA, foreign investment has been greatly stimulated.
Tomatoes are still the most important crop produced in Mexican green-
houses, although cucumbers and peppers have continued to increase in
quantity of production. Continuation of constraint on the entire industry
relates to the volatility of the market for greenhouse products. Generally
with field produced vegetables, many of the Mexican companies have
established contractual agreements both within the local markets within
Mexico, as well as with markets in the U.S. This has allowed them to bet-
ter adjust to price fluctuations. Finally, although Mexico has inexpensive
labor, it is not an absolute low-cost producer because capital and energy
tend to be higher than in North America and in fact, than in the E.U.
Essentially, if premium prices are not continued to be paid for Mexican
produce from the greenhouse, it is potentially possible that these produc-
ers are in danger of going out of business.
It should be recognized that tomato production from greenhouses in
Mexico is still only a small percentage of the total production of tomatoes
being produced and exported from that country. The most significant fac-
tor to concentrate a threat from Mexican greenhouse tomato production
to the Florida market would be the broadening of the greenhouse pro-
duction area. As already experienced, 5-6 other states outside of Sinaloa
that normally would not produce tomatoes in winter now do.
Continuation of high price returns in a high quality market could have a
profound influence on the future for Florida tomato producers.
As to the future of greenhouse tomato production, presently there
are approximately 850 acres of greenhouse tomatoes being produced in
the U.S., or about 6% of the total tomatoes produced in this country. The
major states producing greenhouse tomatoes are Arizona, Texas,
Colorado, and Pennsylvania. On a global scale, Canada is producing
approximately 1600 acres of greenhouse tomatoes, Belgium 1700 acres,
Mexico 1800 acres, and Holland produced 2200 acres. Again, this does
not seem like a lot coming from greenhouses on a world basis, but if one
would look at the statistics of where most of these tomatoes wind up, this
production is in many cases in direct competition with Florida tomato
producers. A last thought to leave however, and one that has been related
by these authors in a previous paper and a previous talk to the Florida
Tomato Institute, is the fact that the world leader, Spain, presently has
well over 50,000 acres of greenhouse space devoted to the production of
tomatoes. Further, as the Spanish greenhouse industry matures and
improves on their marketing abilities, they too will be not only another
competitor, but may be the major competitor for Florida production toma-
to market space in the U.S.

Lopez, J. and K. Shwedel. 2001. The Mexican greenhouse vegetable
industry. Industry Note 032-2001, 5 pp.

'Solar Fire' and Other Hot Tomato

Breeding Topics

J. W. Scott
UF IFAS, Gulf Coast Research and Education Center,

The Fall 2002 Florida tomato season was more stressful than most
as high temperatures and rainfall persisted through October essentially
extending the summer season by a month. This caused severe losses to
growers because the heat depressed fruit set and many of the fruit that did
set were unmarketable due to cracking and rain check from the rains.
There were also serious outbreaks of bacterial spot caused by
Xanthomonas campestris pv. vesicatoria that further reduced yields while
increasing production costs due to increased spraying in attempt to con-
trol the disease. These problems are always present in Florida Fall crops
to some degree. Presently, growers do not have many choices in heat-tol-
erant varieties that will provide desired levels of marketable production
in the fall. Varieties with resistance to bacterial spot and good horticul-
tural characteristics are not available. Today I am going to report on the
release of 'Solar Fire', tested as Fla. 7943B. It is a heat-tolerant tomato
variety that performed well under the very stressful Fall 2002 conditions
and it is anticipated that it will be of benefit to Florida tomato growers in
future years. Secondly, I will briefly report on some new experimental
heat-tolerant varieties that are presently being tested in University and
grower trials. Lastly, I will give an update on development of bacterial
spot tolerant, heat-tolerant varieties.

'Solar Fire'
'Solar Fire' hybrid was released on July 1, 2003. As of this writing
a seed company is being sought for exclusive seed production and distri-
bution rights. A fair amount of seed was produced at GCREC last spring
and testing on a number of grower farms is taking place this fall.
'Solar Fire' has a medium sized, slightly open, vine with good fruit
cover. Pruning is not necessary and heavy pruning would likely be detri-
mental. However, growers might want to experiment with light pruning
to see if there is any benefit under their conditions. The fruit are large
(Tables 1,2), flat-round, smooth, firm (Table 3), have light-green shoul-
ders, and ripen to a good red color (Table 3). The fruit maintain a regular
symmetrical shape and blossom scars are smooth. One of the parents, Fla.
7776, has the nipple type blossom scar (n-2 gene) so the hybrid is het-
erozygous for this gene. The other parent, Fla. 7946, has smooth blossom
scars under a range of growing conditions. The fruit crack less than most
tomato cultivars presently grown in Florida. For instance, there was much
rainfall in the 2002 Fall seasons in Florida and the yield of 'Solar Fire'
was relatively good in part because of the lack of cracking (Table 1).
Maturity is early especially under high temperature conditions (see
Bradenton data in Table 1). The heat-tolerant fruit setting ability of 'Solar
Fire' was illustrated by the marketable yield at Quincy and the early mar-
ketable yield at Bradenton where it was .;'tif 1ri':. greater than the
varieties in Table 1 and all other varieties except for Fla. 7885B (data not
'Solar Fire' is resistant to races 1, 2, and 3 of Fusarium wilt
[Fusarium oxysporum Schlechtend. F. sp. lycopersici (Sacc.) Snyder and
Hansen] (1, 1-2, I-3genes), Verticillium wilt race 1 (Verticillium dahliae
Kleb.) (Ve gene), and gray leafspot caused by 'sI ,.;. I... !, solani Weber
(Sm gene). It has moderate resistance to fruit soft rot (Erwinia carotovo-
ra subsp. carotovora) as indicated by its intermediate water uptake (Table
4). 'Solar Fire' is tolerant of common fruit disorders. There has been
some zippering, blotchy ripening, blossom-end rot, and graywall under
some conditions, but expression of these has not been more than cultivars
presently grown in Florida.

Experimental Heat-tolerant Varieties; Fla. 8092, Fla. 8093,
and Fla. 8135
Several new hybrids are being tested and at least one could be
released in the near future if warranted. Last year I reported some merits
of heat-tolerant inbred Fla. 8044 (Scott, 2002). This inbred has a high
level of heat-tolerant fruit setting ability with good firmness and blossom
scar smoothness. Its vine is not particularly strong. It is a parent in sev-
eral hybrids in my program and crossing in some seed company programs
has taken place. The three hybrids of most interest at present with Fla.
8044 as a parent are Fla. 8092, Fla. 8093, and Fla. 8135. All yielded well
in the Spring trial at GCREC (I ii, I dJ et al., 2003). Seed has been lim-
ited up to now but crosses made in Spring 2003 now allows for more test-
ing in Fall 2003. In a very stressful Summer 2002 trial where all mar-
ketable yields were depressed from heat, rain, and bacterial spot inci-
dence, Fla. 8093 had ,;-i.ifK nri'. more marketable yield than all other
hybrids tested (Table 5). Fla. 8094 also has Fla. 8044 as a parent, thus
three of the four highest yielding hybrids had Fla. 8044 as a parent. Of
the Fla. 8044 hybrids, Fla. 8092 has the strongest vine. It had more zip-
pering than desired in Spring 2003, but will be tested more in the future.
Zippering is generally more severe under cool conditions. Other hybrids
in advanced testing are Fla. 7973 and Fla. 7964. They might be released
soon and were described last year (Scott, 2002). Additional hybrids
including some heat-tolerant, spotted wilt resistant types have shown
some potential, but it is premature to discuss them here as testing has
been limited.

Bacterial Spot Tolerance
One of the problems in developing bacterial spot tolerant varieties
for Florida growers is that there are several races of the pathogen. There
are presently four races that infect tomato and three of these have been
identified in Florida. The original race was T1 and breeding that started
in 1983 focused on incorporation of resistance from the small-fruited
accession Hawaii 7998. In 1991, before commercially acceptable T1
resistant varieties were developed, race T3 emerged in Florida and it has
now largely replaced T1. Studies have shown that T3 is antagonistic to
Tl, which helps explain its prevalence (Jones et al., 1998). Breeding for
race T3 is based on incorporation of resistance from Hawaii 7981, anoth-
er small-fruited accession. Hybrids with heterozygous T3 resistance (one
of the two parents is resistant, the hybrid resistance level is intermediate
between the parents) are presently being evaluated for possible release.
Heterozygous resistant hybrids had very good resistance under heavy
bacterial spot infection in North Florida in Fall 2002. One of the hybrids,
Fla. 8217, had good horticultural type in a Homestead trial in Winter
2003. In Homestead it looked better than Fla. 8224 (Table 5) which is
closely related. Several hybrids have been tested at GCREC during the
last year and a few show some promise and will be tested in the future.
Meanwhile, T4 has recently been identified in Dade and Manatee coun-
ties and it may be present elsewhere (Astua-Monge et al., 2000). It is not
known how widespread and prevalent this race will become. It was
severe in 2002 summer breeding plots at GCREC. Whereas it rendered
most T3 resistant breeding lines susceptible, we did discover that PI
114490 had resistance. This resistance was confirmed in Spring 2003
when T4 was again present in breeding plots. PI 114490 had earlier been
shown to have resistance to race T2 in Ohio experiments (Scott et al.,
1997). Race T2 has not been found in Florida. PI 114490 also has resist-
ance to race T1 (conferred by the same two genes as race T2) and partial
resistance to race T3 (Scott et al., 2003). In Summer 2002 and Spring
2003 we also found breeding line Fla. 8233, with PI 114490 and the
Hawaiian accessions in its pedigree, to be resistant to race T4. Growth
chamber experiments indicated that this line has hypersensitive resistant
reactions to races T1 and T3. This line and some others will be field test-
ed for resistance to races T1 and T2 in Ohio in Summer 2003. Possibly
Fla. 8233 has resistance to all four races. This is important because it may
have a durable resistance that will be effective against any future races
that may emerge. Furthermore, Fla. 8233 has heat-tolerance, medium

fruit size, and other desirable characteristics. Thus, development of com-
mercially acceptable varieties may not take as long as previous breeding
efforts using Hawaiian accessions for resistance to races T1 and T3.
Numerous crosses were made with Fla. 8233 in Fall 2002 and Fl's are
being advanced to the F2 generation in spring 2003. Selections of the F2's
will take place in late summer 2003. Two of the hybrids even appeared to
be near commercial acceptability in Spring 2003. It is not realistic to
assume that the two will actually be acceptable for release, but it does
illustrate that Fla. 8233 is a good horticultural source to begin this breed-
ing effort. Over 20 years of a concerted breeding effort has not resulted
in a bacterial spot resistant release. Perhaps the tide is turning.

Literature Cited
Astua-Monge, G., G.V. Minsavage, R.E. Stall, C. Eduardo Vallejos, M.J.
Davis, and J.B. Jones. 2000. Xvr-avrxv4: A new gene-for gene interaction
identified between Xanthomonas campestris pv. vesicatoria race T3 and
the wild tomato relative Lycopersicon pennellii. Mol. Plant-Microbe
Interact. 13: 1346-1355.

Bartz, J. A. 1991. Relation between resistance of tomato fruit to infiltra-
tion by Erwinia carotovora subsp. carotoora and bacterial soft rot. Plant
Dis. 75:152-155.

Jones, J. B., H. Bouzar, G. C. Somodi, R.E. Stall, K. Pernezny, G. El-
Morsy, and J.W. Scott. 1998. Evidence for the preemptive nature of toma-
to race 3 of Xanthomonas campestris pv. vesicatoria in Florida.
Phytopathology 88:33-38.

Maynard, D.N., J. W. Scott, and B. J. Sidoti. 2003. Tomato variety eval-
uation, Spring 2003. GCREC Research Report BRA-2003-(in press).

Scott, J.W. 2002. Project stating and possible variety releases from the
IFAS tomato breeding program. Proc. 2002 Florida Tomato Institute.

Scott, J.W., S.A. Miller, R.E. Stall, J.B. Jones, G,C. Somodi, V. Barbosa,
D.L. Francis, and F. Sahin. 1997. Resistance to race T2 of the bacterial
spot pathogen in tomato. HortScience 32:724-727.

Scott, J.W., D.M. Francis, S.A. Miller, G.C. Somodi, and J.B. Jones.
2003. Tomato bacterial spot resistance derived from PI 114490;
Inheritance of resistance to race T2 and relationship across three
pathogen races. J. Amer. Soc. Hort. Sci. 128(4):(in press).

Table 1. Marketable yield and fruit size for tomato genotypes under high temperature conditions in North (Quincy) and West Central
(Bradenton) Florida in Fall, 2002.

Quincy, Florida Bradenton, Florida

Marketable yield Early marketable yield Total season marketable
(25 lb cartons/A) (25 lb cartons/A) yield
(25 lb cartons/a)

Fruit size Fruit size
Genotype Total Extra (g) Total Extra large Total Extra large (g)
'Solar Fire' 1641 az 1156 a 183 a 1083 a 954 a 1480 a 1235 a 187 ab
'Solar Set' 1398 b 799 b 159 b 740 b 609 b 1461 a 1085 ab 176 b
'Florida 47' 1221 bc 732 b 163 b 430 c 354 c 908 b 729 b 176 b

'Florida 91' 1126c 751b 173 ab 780 b 707 b 1307 ab 1136 a 196 a

ZMean separation within columns by Duncan's multiple range test at P < 0.05 based on a larger number of genotypes.

Table 2. Marketable yield, fruit size, and culls for selected tomato genotypes in Spring 2002 at Bradenton, Florida.

Marketable Yield Fruit size Culls
Genotype (251b. Boxes/A) (g) (% by wt.)

'Solar Fire' 3610 az 189.7 10.4 c

'Floralina' 2637 ab 169.0 23.7 b

'Sanibel' 2602 ab 190.5 37.7 ab

'Florida 47' 2587 ab 185.4 39.0 ab

'Solar Set' 2412 b 176.3 43.3 a


zMean separation in columns by Duncan's multiple range test at P <0.05.

Table 3. Firmness and fruit color for selected tomato genotypes in Fall 2002 at Bradenton, Florida.

Firmnessz External Fruit Color'
Genotype (mm deformation) L Hue Angle

'Solar Set' 4.1 ax 45.5 d 48.2 c

'Florida 91' 3.1 b 47.3 b 50.8 b

'Solar Fire' 3.0 b 46.4 c 49.8 b

'Florida 47' 2.7 b 48.2 a 52.4 a

Internal Fruit Color
L Hue Angle

48.1 52.5 b

49.8 53.1 ab

48.6 52.2 b

49.6 54.5 a


ZDetermined with a pressure tester using a 1 kg. weight for 5 seconds with a fruit contact plate 1.5 cm in diameter. Pressure applied
over a locule in equatorial plane.

'Data taken with a Minolta CR-300 chromameter; higher L values indicate lighter color (value), lower hue angles indicate more red
color (hue).

xMean separation in columns by Duncan's multiple range test at P <0.05.

Table 4. Water uptake for fruit of tomato genotypes immersed in water for three minutes.

Cultivar Fruit wt. (g) Water uptakey

'Solar Fire' 210 bx 1.09 b
Fla. 7964 186 c 1.13 b
'Florida 47' 205 b 2.02 a
'Florida 91' 234 a 1.68 a
'Solar Set' 199 b 0.76 c

zFor all columns, values equal the average of 10 fruit selected from harvest of four field plots.

YData were adjusted for fruit size and relate to soft rot susceptibility where less uptake
means more tolerance to soft rot (Bartz, 1991).

xMean separation in columns by Least Square Means test at P 0.05.

Table 5. Marketable yield, fruit size, and culls for tomato genotypes at Bradenton,
Florida, Summer 2002.

Fla. 8093
HMX 1803
Fla. 8094
Fla. 8092
Fla. 7885B
Fla. 7964
Fla. 8224
'Sun Chaser'
'Solar Set'
'Florida 91'
'Florida 47'

Marketable Yield
(25 lb cartons/A)
1052 az
711 b
681 b
539 bc
510 bc
428 b-d
372 b-d
297 cd
205 d
198 d
157 d

Fruit Size
5.6 a
6.0 ab
5.7 a-c
6.1 a
5.4 a-c
5.1 a-c
5.6 a-c
4.5 c
4.8 bc
6.4 a
5.4 a-c

(% by wt.)
43.7 c
59.2 a-c
49.0 c
57.8 b-c
57.8 b-c
61.9 a-c
71.1 a-c
75.5 ab
80.0 a
73.9 ab
80.8 a

zMean separation in columns by Duncan's multiple range test at p :0.05.

Tomato Yellow Leaf Curl Virus Revisited

J. E. Polston
UF IFAS, Plant PEoi. 1J.,.iv Department, Gainesville

Tomato yellow leaf curl virus (TYLCV) is one of the most econom-
ically significant and damaging viruses to tomato. Unfortunately it is also
one of the most difficult viruses of tomato to manage. A solid under-
standing of the annual disease cycle of TYLCV is very helpful in the suc-
cessful management of TYLCV. However, the disease cycle of TYLCV
varies among the Jtt.c!! ir tomato production regions in Florida (see
Proceedings of the Tomato Institute 2002 for diagrams of these cycles.
[http://www.imok.ufl.edu/veghort/index.htm] )
It is expected that recommendations for successful management of
TYLCV will be adjusted as production practices change and as new
information regarding the pathogen/pest is obtained. With that in mind,
there are 3 items that must now be considered in the management of
TYLCV, and they are:

*The gradual expansion of the tomato production period and
the decrease in size of the tomato-free periods
*The increase in production of grape tomatoes
*A new crop host of TYLCV

Expansion of the tomato production period and the decrease in
size of the tomato-free periods. Tomato production seasons have been
increasing in length over the last few years. This has resulted in the reduc-
tion in size or in some locations in the elimination of tomato-free periods
in the summer and winter. Tomato-free periods of about 2 months in the
summer and 1 month in the winter are very important tools for manage-
ment of TYLCV and for management of insecticide resistance in white-
flies. The reduction and/or elimination of these tomato-free periods is
having an undesirable impact on incidences of TYLCV-infected plants
and on the susceptibility of' ILct,.r-!i to insecticides including imidaclo-
prid and thiamethoxam.

The increase in production of grape tomatoes. A problem related
to the increase in tomato production seasons is the long crop cycle
employed in grape tomato production. Grape tomatoes are in the ground
for up to 9 months or even more in some cases. Because of their long time
in the field, grape tomatoes are acting as a good reservoir of' Iltric-!l
and TYLCV.
Incidences of TYLCV-infected plants can become quite high in
grape tomato fields. This is due to several reasons. Fruit is being harvest-
ed for a large percent of the time that the plants are in the field, so only a
limited number of pesticides, representing a limited number of classes of
pesticides, can be applied for whitefly and TYLCV management. In addi-
tion, other virus management practices such as rouging and reflective
mulches are less effective due to the long duration of the crop.
In addition, tomato plants in the field this long are good places for
the development of pesticide resistance in ,' Ii ti!l Many generations
of '- Ir!itl.- can be produced in these fields. Since these fields are
sprayed in iu:. r;uim, ;rii ;in r;i ;iJ, there is a good opportunity to select
for Itrc!iic- which are more tolerant to the insecticides being applied.
Whiteflies with greater tolerance to insecticides mean higher incidences
of TYLCV-infected plants in successive plantings.
Right now there are no obvious recommendations that can be fol-
lowed to minimize the impact of long season grape tomatoes (maintained
for more than 5 months) on tomato production in the region. There is sub-
stantial circumstantial data that shows that Inr-!l ,ti and TYLCV can
move many miles from a source of virus. The greatest impact is within 6
miles downwind although impacts have been felt within 10 miles or
more. It is difficult to control Ilnrc!li in mature tomato plants due to

the dense foliage. Tomatoes that are being harvested can be sprayed with
very few insecticides so optimal whitefly management is not possible. In
terms of TYLCV management, roguing would remove too many of the
plants, and reflective mulches lose their ability to reflect light after a few
months in the field.

A new crop host of TYLCV. Earlier this year we determined that pepper
(Capsicum annuum) can be infected by TYLCV. We are in the process of
screening pepper cultivars that are grown in Florida for resistance to
infection by TYLCV. The information we have to date is shown in Tables
1, 2 and 3. A few cultivars that we tested were immune to infection with
TYLCV (Table 1) but most cultivars could be infected (Table 2). No
foliar symptoms were seen on any of the infected plants and fruit on
infected plants appeared unaffected. Although many cultivars could be
infected (Table 2), the rates of transmission to pepper were lower than
those to tomato. In many cases we were only able to infect a few pepper
plants out of 10 when we used 40 to 100 viruliferous ', ir-!iil,- These
lower rates of transmission are most likely due to the Int, r- i-' feeding
preferences; Florida whitefly populations feed more readily on tomato
than pepper. Similar conditions using tomato plants would result in 100%
infection of the tomato plants being tested. We also found t Iir I r tlc,
which fed on TYLCV-infected pepper plants could acquire virus and
infect healthy tomato plants. To summarize, pepper is a host of TYLCV,
most cultivars are susceptible, -Initr!l can acquire TYLCV from
infected pepper plants, but pepper is a more difficult host to inoculate
than tomato.
These data imply that, in the field, pepper could serve as a reservoir
of TYLCV but it is not clear yet how important a role pepper is or will
play. It is clear that right now tomato plants are a much better source of
TYLCV than pepper. However, the ability of pepper to serve as a source
of TYLCV will depend upon the populations of' l Ir-iiCt present in the
pepper fields, the proximity of the pepper field to an old (and TYLCV-
infected) tomato field, and proximity to a young and vulnerable tomato
field. Further studies will be conducted to determine how frequently
TYLCV-infected pepper plants occur in the field and the significance of
pepper in epidemics of TYLCV in tomato. Until then, if growers suspect
that peppers are playing a role in their area, they can select pepper culti-
vars which are immune to TYLCV (Table 1).

Although the timing of field production and harvest is usually based
primarily on market prices, the consequences of such timings on disease
and insect management should be taken into consideration, since these
consequences will be felt in costs of production. Field production that
creates small or absent tomato-free periods will cause increases in inci-
dences of TYLCV-infected plants, and increases in the resistance of
-t I tr!iLc, to insecticides. Production of grape tomatoes for more than 4
to 5 months eliminates the tomato-free period, provides a good reservoir
of TYLCV, and is an excellent location for the development of whiteflies
with resistance to insecticides. Tomatoes are still the best reservoir of
TYLCV. Peppers are probably not a significant source of TYLCV yet,
although as whitefly populations increase in peppers it is likely to become
a more important reservoir
in the future.

Management Tactics for TYLCV A Review
Following is a list of the methods used to manage TYLCV. Many of
these should be used at the same time. However, even all these methods
combined have been shown to be inadequate when a source of TYLCV-
infected plants that have moderate to high populations of viruliferous
SlLr ti-L, is within a few miles of a field of young susceptible crop plants.
Chemical Control of Whiteflies. As with other plant viruses which
can be transmitted for long periods of time by their insect vector, sup-
pression of the vector can provide an effective means of reducing virus
spread within a field, and from field to field. Management of bego-

moviruses I I nt'l-, r .i-.i.rtc,.l geminiviruses) through applications of
insecticides is expensive but is effective in many situations. Several sys-
temic and foliar-applied insecticides are available for killing whitefly
adults and immatures.
At the beginning of the season, imidacloprid (AdmireM) or thi-
amethoxam (Platinum"M) should be applied as a soil drench in the trans-
plant house one week before transplant to the field. This is designed to
interfere with whitefly feeding and TYLCV transmission, and can protect
the transplants in the field for up to 2 weeks. Imidacloprid (AdmireM) or
thiamethoxam (Platinum"M) should be added to the setting water at the
time of transplant at a rate that will protect the plants for approximately
8 weeks (AdmireM, at 16 oz./A, or Platinumr" at 8 oz./A). The insecticide
application in the greenhouse protects the transplants during the few days
that it takes for these chemicals to be taken up by the plants in the field.
These initial drenches should be followed by a rotation of foliar-
applied insecticides once whitefly reproduction is observed in the field.
Several foliar insecticides are available and should be applied when
immature densities exceed a population density of 5 per 10 leaflets (the
terminal leaflet of the 7th-8th leaf from the top of 10 plants/2 acres). The
most effective rotation is the use of the insect growth regulators Knack"
(10 oz./A) and Applaud-M (0.5 lb/A). If applied at the population thresh-
old previously described, whitefly populations can be managed with a
minimal number of applications. If adults are seen in the field, a mixture
of ThiodanrM plus a pyrethroid is effective. It is very important not to fol-
low the use of AdmireM or PlatinumrM with ProvadoTM. Imidacloprid and
thiamethoxam are the same class of insecticides (neonicotinoid). Using
these in rotation will only increase the chances of' Iirctil.1- developing
resistance to this class of insecticides. When applying foliar insecticides,
it is essential to maintain good coverage on the underside of the leaves
where It Lt1i. reside. Good whitefly control during the last few weeks
of the crop will reduce the carry over of ,- Ir- tle, and virus to the next
planting. It is important to use all these insecticides at the label rates and
to pay attention to re-entry and pre-harvest intervals.
Biological controls, which often work well in the absence of broad-
spectrum pesticides to reduce the impact of the whitefly as a pest, at this
time do not offer sufficient control of the vector to reduce the incidence
of TYLCV-infected plants.

Cultural Practices
Cultural practices should be used in combination with the chemical
practices mentioned previously. Several cultural practices have been
shown to be beneficial in reducing incidences of TYLCV-infected toma-
to plants.
Sanitation. Since yield losses from TYLCV are more severe the ear-
lier in the season the infections begin, nearby tomato plantings that have
TYLCV-infected tomato plants are very important sources of I1 -ctlc-
and virus. New plantings, especially those downwind of the older fields,
are extremely vulnerable to infection by TYLCV. Removal of tomato
plants promptly after harvest is an important component of an effective
management program.
Virus-free Transplants. When possible, tomato transplants should
be purchased from production sites that are not located near tomato
fields. This reduces early infections and reduces the amount of TYLCV
introduced into the field. Transplants should be treated with imidacloprid
one week prior to transplanting.
The use of pymetrozine (FulfillT) has been shown to protect toma-
to transplants in the planthouse from infection with TYLCV. Pymetrozine
is a feeding inhibitor, and acts very quickly. Once Iitr t-iI probe treat-
ed plants, feeding stops (ie transmission of TYLCV is not possible) and
lIractic, die within 24 hours due to dehydration. Current label instruc-
tions dictate that pymetrozine can be applied twice in a production cycle
at one-week intervals. Foliar sprays of other insecticides can be used to
kill adults that alight on transplants but these usually have little effect on
virus transmission since they do not act fast enough to interrupt feeding
behavior. Imidacloprid is not registered for use in transplant production

except for an application in the last week of production for protection in
the first two weeks in the field.
Roguing. During the first few weeks of the crop, fields should be
inspected for TYLCV-infected plants. All symptomatic plants that are
found should be rogued from the field. This will eliminate these plants are
sources of virus for nearby plants later in the season when whitefly con-
trol is less effective.
Reflective Mulches. Studies in Florida have shown that reflective
mulches, which cause '- Ir-ctl.,- to become disoriented, are more effec-
tive in reducing the incidence of Tomato mottle virus (ToMoV) than yel-
low plastic mulches. These mulches would be expected to reduce inci-
dences of TYLCV-infected plants. Reflective mulches have the added
advantage of disorienting aphids and reducing the incidences of aphid-
borne viruses like Potato virus Y and Tobacco etch virus.
Weed Control. The importance of weeds in TYLCV epidemics in
Florida is not clear. Many times high incidences are easily correlated with
proximity to older tomato fields that have TYLCV-infected plants and
high whitefly populations. Although in Cyprus, eradication of over-win-
tering weed hosts I.;.-.'Lf idri:. reduced the incidence of TYLCV, the
same approach was not effective in Israel. The importance of weeds in
TYLCV epidemics has not been established. The identities of the weed
species that play a role, however minor, in the spread of TYLCV have
also not yet been determined. It is 1; -i,. ri ir rii l weed species that do play
a role will vary among the J. tt i o-i production regions in the state.
Trap Crops. The use of trap crops of squash, a highly preferred
whitefly host, delayed TYLCV spread when planted 30 days before in
alternate rows with tomatoes. Studies indicate that the larger the land
allocated to the trap crop, the more effective it will be. Trap crops are
more effective for small plots of tomatoes. The optimal ratio of trap crop
to tomato has not yet been established.
Resistant Cultivars. Fresh market tomato hybrids with resistance to
TYLCV have been evaluated in Florida. Several cultivars produced sig-
iifL ilrl-'. greater yields compared to the common commercial cultivars
when grown in the presence of high TYLCV and ILc, tlic- These culti-
vars also produced acceptable yields and fruit quality in the absence of
TYLCV. Hazera Genetics, Inc. and Seminis Inc. (Petoseed) are two seed
companies with TYLCV-resistant cultivars. In addition, Gemstar is a tol-
erant processing or saladette-type tomato from Petoseed that has resist-
ance to TYLCV. At this time, all the hybrids being released have toler-
ance but not immunity to TYLCV. Early infections of these cultivars with
TYLCV and high populations of 1I -thil.c, carrying TYLCV will over-
come the resistance present in all commercially available cultivars.
For optimal results, these resistant cultivars should be used in com-
bination with the other management practices. Resistant cultivars can be
used with the greatest effect by selecting these cultivars for production
when incidences of TYLCV-infected plants are expected to be at their
highest. This would be in the first two plantings in the fall in West Central
Florida, the last planting or two in Southwest Florida, and any planting
where a large source of TYLCV is expected or known to be within a few
miles. Resistant plants will be infected but good yields can still be
obtained. It is important to remember to use good whitefly control prac-
tices since these resistant cultivars can serve as sources of TYLCV for
later planted or near-by susceptible cultivars. At times of the year when
virus pressure is expected to be lower, other desired cultivars can be used.

Table 1. Pepper cultivars with immunity to TYLCV.

Cultivar Fruit Type Seed Source
'Double Up' Bell, green-red Sakata
'Red Rooster' (spur pepper) Ornamental Unknown
'SPP0615' Jalapeno Sakata
'Sweet Banana' Banana Ferry Morse
'Tiburon' Poblano Sakata

Table 2. Pepper cultivars with susceptibility to TYLCV.

Cultivar Fruit Type Seed Source
'Brigadier' Bell, green Rogers
'California Wonder' Bell, green American Seed
'California Wonder 300TMR' Bell, green Ferry Morse
'Camelot X3R' Bell, green Seminis Petoseed
'Cascabella' Hot, cone Ferry Morse
'Crusader' Bell, green Rogers
'El Rey' Jalapeno Sakata
'Long Hot' Cayenne Seminis Asgrow
'Olympus' Bell, green-red Enza Zaden
'Orion' Bell, green Enza Zaden
'Pepper Grande Jalapeno' Jalapeno Seminis Asgrow
'SCM334' Wild serrano Sakata
'Senorita' Red "cheese" Sakata
'Sentry" Bell, green-red Rogers
'SPP0132' Bell,green-orange Sakata
'Stilleto' Bell, red Rogers
'Twist Sweet' ??? YuAnFarms (Korea)
'Wizard X3R' Bell, green Seminis Asgrow
'XPP0701' Anaheim Sakata

Table 3. Cultivars still under study.

Cultivar Fruit Type Seed Source
'X3R Aladdin' Bell, yellow Seminis
'X3R Aristotle' Bell, red Seminis
'Heritage' HMX 1640 Bell, red Harris Moran
'Hungarian Hot Wax' Hungarian Hot Wax Dessert Seeds (Petoseed)
'Patriot' HMX 640 Bell, red Harris Moran
'Pepper Grande' Bell, green Seminis Asgrow

What's Up With All These Whiteflies?

David J. Schuster, Sandra Thompson
UF/IFAS, Gulf Coast Research & Education Center, Bradenton

Phyllis R. Gilreath
UF/IFAS, Cooperative Extension Service, Manatee County,

The silverleaf whitefly (SLWF), Bemisia ,..,...r .. Bellows &
Perring [also know as the B strain of the sweetpotato whitefly, B. tabaci
(Gennadius)], remains the key pest of tomatoes in southern Florida. B.
,. ,.... -. .. causes losses by inducing the irregular ripening (IRR) disor-
der of tomato fruit and by transmitting geminiviruses, the most damaging
of which is tomato yellow leaf curl virus (TYLCV) (Schuster et al. 1996).
Despite applications of the nicotinoid Admire 2F (imidacloprid; Bayer
CropScience, Kansas City, MO) to seedlings in plant production houses
and additional soil applications of either Admire or Platinum (thi-
amethoxam; Syngenta Crop Protection, Inc., Greensboro, NC), another
nicotinoid, at transplanting or up to three weeks Ifii- rI f ,pii Ir,; toma-
to growers in every production area in southern Florida experienced larg-
er than normal numbers of whitefly adults during the past spring season.
This was particularly true late in the season. Because of the threat of
transmission of TYLCV by these whitefly adults, numerous applications
of additional insecticides were applied, sometimes weekly or more fre-
quently, even though the soil applications of Admire or Platinum were
still providing control of whitefly nymphs.
Insecticides applied included Fulfill (pymetrozene; Syngenta Crop
Protection, Inc., Greensboro, NC), Monitor (methamidophos; Valent
U.S.A. Corporation, Walnut Creek, CA), Lorsban 50-W (chlorpyrifos;
Gowan Company, Yuma, AZ), several Jitr -i',i pyrethroids, Phaser
endosulfann; Bayer CropScience, Kansas City, MO), Thiodan (endosul-
fan, FMC Corporation, Agricultural Products Group, Philadelphia, PA),
soap and oil. Results were mixed and residual control was short. Some
growers made foliar applications of nicotinoids including Provado
(imidacloprid; Bayer CropScience, Kansas City, MO), Actara (thi-
amethoxam; Syngenta Crop Protection, Inc., Greensboro, NC), and
Assail (acetamiprid; Cerexagri, Inc., King of Prussia, PA), again with
mixed results. This practice could encourage the development of resist-
ance to the nicotinoid insecticides (Elbert and Nauen 2000).
Naturally, growers are asking why so many whitefly adults are pres-
ent and persist despite these many insecticide applications. Are the white-
flies becoming resistant to the insecticides? Are there other cultural activ-
ities that are contributing? What can we do now and what are the control
prospects for the future? What follows is an attempt to answer these ques-

Resistance and Resistance Monitoring
Certainly, the pyrethroids, endosulfan (Thiodan, Phaser) and
organophosphates (Monitor, Lorsban) are not as effective against the
SLWF as they once were, although no systematic or long-term monitor-
ing of efficacy or resistance has been conducted in Florida. As early as
1991, up to an 80% reduction in efficacy of endosulfan and up to a 60%
reduction in efficacy of Lorsban relative to a susceptible colony were
observed in field populations using a laboratory bioassay (Stansly et al.
1991). There is no reason to expect a reversal of these trends, especially
in light of the current heavy use of these insecticides.
A cut leaf petiole method was developed to compare the suscepti-
bility of field populations of the SLWF to Admire with that of a highly
susceptible laboratory colony (Schuster and Thompson 2001, Schuster et
al. 2002). The method was used to evaluate the relative susceptibility of
SLWF populations from 9 Admire-treated tomato fields in 2001, 14 fields

in 2002, and 10 fields in the spring of 2003. At least three of the fields in
2003 were treated at transplanting with a soil application of Platinum
rather than Admire. Bioassays were conducted using adults reared from
foliage infested with nymphs that had been collected from each tomato
field. Standard probit analyses (SAS Institute 1989) were used to estimate
the LC50 values (the concentration estimated to kill 50% of the popula-
tion) for the laboratory colony and for each field. The relative suscepti-
bility (RS50) of each field population compared to the laboratory colony
was calculated by dividing the LC50 values of the field populations by the
LC50 value of the laboratory colony. Increasing values greater than one
suggest decreasing susceptibility in the field population.
Over 2001 and 2002, nearly 80% of the RS50 values of'- Irt-!ia-.
collected from the Admire-treated fields were 8 or less, while in 2003,
only about 20% of the fields had values of 8 or less (Tables 1 & 2). While
values approaching 8 could indicate decreasing susceptibility of the
h Iirctlic-, such variability is not unexpected when comparing field-col-
lected insects with susceptible, laboratory-reared insects. The laboratory
colony used as a susceptible standard in this study has been in continuous
culture since the late 1980's without the introduction of,' lrc-!lI, col-
lected from the field and, therefore, would be anticipated to be particu-
larly susceptible to insecticides. RS50 values of 10 or greater were
observed in three whitefly populations in 2001, four populations in 2002
and eight populations in 2003. This represent about 20% of the popula-
tions in 2001, 30% in 2002 and 80% in 2003. Values of 10 or greater are
sufficiently high to draw attention, especially those of 20 or higher.
Certainly, the higher proportion of high values observed in 2003 would
suggest a decrease in susceptibility of the SLWF in 2003 relative to pre-
vious years. While this may be the case, there may be extenuating cir-
cumstances to explain the high values.
First, eight of the populations sampled in 2003 were all sampled in
June within about 10 days of each other and when harvesting had been
completed or was soon completed. Therefore, all of these whitefly popu-
lations would have had the maximum potential exposure to nicotinoid-
treated tomato plants, and the movement of whitefly adults among
senescing and abandoned fields could result in a mixing of whitefly pop-
ulations, resulting in more homogeneous whitefly responses to Admire.
This latter hypothesis would be supported by the low value observed in
the whitefly population from Myakka City, which is isolated from the
other populations sampled. On the other hand, the sites in Ruskin were
adjacent to one another, yet one field had a low value and the other had a
high value. In addition, when only considering fields sampled in June, the
above percentages of fields with RS50 values of 10 or greater were about
the same (Table 2). Thus, the time of sampling may have had an impact
but is not the entire explanation.
The progeny of adults that survived the bioassay from the Duette site
in 2001 and the SWFREC site in 2002 were reared for 6-8 wk (about 2-
4 generations) on tomato in the laboratory and then bioassayed again. The
RS50 value of the progeny of the bioassay survivors from the Duette site
in 2001declined from 8 to less than 2 after being reared in the laboratory
for about 8 wk without exposure to Admire (Table 3). Similarly, the RS50
value of the progeny of the bioassay survivors from the SWFREC site in
2002 declined from nearly 22 to less than 6 after being reared in the lab-
oratory for about 6 wk. In addition, the RS50 value of the progeny of the
bioassay survivors from a whitefly population collected from green-
house-grown poinsettia in northwest Florida in 2002 likewise declined
from 21 to less than 4 after being reared in the laboratory for about two
generations (Schuster, unpublished data). At the Immokaleel site in
2001, whitefly-free, greenhouse-grown tomato plants were placed on the
field perimeter about 4 wk after the crop had been destroyed. One week
later, the plants were returned to the laboratory and held 4-5 wk (about 2-
3 generations) and the progeny bioassayed as before. The RS50 value for
the whitefly population collected 4 wk after the end of the crops at the
Immokaleel was about 2 compared to 15 while the crop was still in the
field (Table 3). Thus, decreased susceptibility to Admire indicated in
these studies, especially late in the spring season, will probably dissipate

or disappear during the off-season, if the off-season is sufficiently long

Efficacy of Nicotinoids for Whitefly Control
The reduced susceptibility of the SLWF suggested in the monitoring
study would suggest reduced control. Unfortunately, efficacy data were
not collected in any of the fields sampled for the survey; however, none
of the growers indicated a failure to control whitefly nymphs during the
season and didn't note a large increase in the whitefly population until
late in the crop when the controlling effects of the Admire or Platinum
would have diminished. In addition, comparisons of soil applied Admire
and Platinum at transplanting with check plots were conducted in exper-
iments at two commercial farms and in one experiment at GCREC. In all
of these trials, both Admire and Platinum generally kept the numbers of
whitefly nymphs below the threshold of 5/10 leaflets (Schuster 2002) for
at least 8 wk and usually beyond (Fig. 1). Significant dittc!!-..L were
detected between the treated and non-treated plots in every experiment on
at least some dates. The populations in the commercial fields were too
low to acquire samples large enough to bioassay for susceptibility to
Admire and heavy rains caused rapid destruction of foliage at GCREC.

Nicotinoid Availability and Application Methods
In 1994, imidacloprid formulated as Admire for soil applications and
as Provado for foliar applications was the only nicotinoid insecticide
available to Florida tomato growers. Since then, Platinum/Actara (soil
and foliar formulations, respectively, of thiamethoxam) and Assail have
become available. Essentially all tomato growers in south Florida use
either Admire or Platinum applied to the soil to manage the SLWF and
TYLCV. Because of the increasing numbers of whitefly adults and the
increasing threat of TYLCV, some growers have followed these soil
applications with foliar applications of Provado, Actara or Assail. All of
these compounds are in the nicotinoid chemical class and cross-resistance
has been documented in Spain to both imidacloprid and thiamethoxam
(Elbert and Nauen 2000). Therefore, following soil applications of a
nicotinoid insecticide with foliar applications of nicotinoid insecticides
may contribute to the increasing RS50 values for Admire and are not rec-
Nearly all, if not all, tomato seedlings are treated with Admire in the
production house 7-10 days prior to transplanting to ensure that the
seedlings have absorbed sufficient Admire to protect them against white-
flies that may infest them immediately after transplanting. The length of
protection of this production house application may be up to 2-3 wk;
therefore, some growers delay applying either Admire or Platinum to
transplants in the fields for up to three weeks. These applications are
made through the existing drip irrigation system established in the field.
Some growers split applications of Admire or Platinum in an attempt to
lengthen the period of control in the field. While there is no experimen-
tal evidence quantifying the efficacy of applying Admire or Platinum
through drip irrigation tubing, anecdotal observations suggest that the
nicotinoids are not as efficacious when applied through the drip tube as
when they are applied in the transplanting water. Furthermore, repeated
applications through the drip system lengthens the period of exposure of
SlIhctlic, to Admire or Platinum. Therefore, it is recommended that
growers apply the nicotinoids in the transplanting water and switch to
chemistries other than the nicotinoids as the controlling effect of the soil
application diminishes.

Changes in Cropping Practices
The generalized changes in RS50 values over time are depicted as
"Now" in Fig. 2. Relatively low RS50 values would be expected when
tomatoes are planted in the fall and would increase during the fall and
spring seasons, peaking in June as harvesting ends. There could even be
an intermediate peak not depicted in Fig. 1 that would occur as crops
planted in the fall are destroyed and ,- It-!l,,l exposed to nicotinoid
insecticides in the fall plantings migrate to spring plantings. At any rate,

the level at which RS50 values occur at the beginning of the fall season
probably are related to the level that occur at the end of the previous
spring season and the length of the tomato off-season. Fig. 3 shows a gen-
eralized depiction of tomato production that occurred in west central
Florida 5 or more years ago ("Then"). At that time, tomatoes generally
were not planted until mid- to late August and fields were destroyed dur-
ing mid-December. Spring plantings generally were delayed until late
January to escape killing frosts and fields destroyed by the first week of
June. Due to economic and crop considerations, the tomato cropping
cycle has changed dramatically ("Now"). Planting begins in late July and
fields are not destroyed until late December, if then. Spring plantings
begin in early to mid-January and fields may still be in production in mid-
June. The result of these changes is that there is little or no tomato-free
period in the winter and only about one month in the summer. The trend
toward an ever-shorter, tomato-free period in the summer may be caus-
ing, at least in part, the decreased susceptibility of I- t!l1 ,- to Admire
in the spring. If this trend is not reversed, growers may be facing even
higher levels of reduced susceptibility to Admire in the future (Fig. 2,
"When?"). While this generalized version of changes in cropping sched-
ules is for west central Florida, similar changes have occurred in the other
tomato producing areas of Florida.
There are many factors causing the changes in cropping schedules.
Historically low prices during peak tomato production have encouraged
growers to plant earlier in the fall to try and capitalize on the higher prices
early tomatoes usually gain. Growers also may plant later spring crops
and continue maintaining these crops late in the spring in hopes of capi-
talizing on higher prices sometimes experienced later in the spring sea-
son. U-pick operations are often continued to capture additional revenue
from crops -1, r 1i ,:. not have provided much return earlier in the season.
U-pick fields from the fall season may still be in production when spring
fields are being transplanted, thus erasing the crop-free period in the win-
ter. Spring fields opened for u-pick may still be in production in mid-June
or beyond, thus shortening the crop-free period in the summer.
Grape tomatoes are popular among consumers and, as a result, are
popular among Florida tomato growers. Grape tomatoes are a longer-
termed crop than slicing tomatoes and are often the first planted crop in
the fall and the last destroyed crop in the spring. They may be planted
adjacent to or near new tomato crops and crops planted later in the fall
may still be in harvest as the spring fields are transplanted. Thus, grape
tomatoes may bridge the fall and spring tomato crops, eliminating the
crop-free period in the winter, and crops planted in the spring may be in
production in mid-June, shortening the crop-free period in the summer.
Because they are often planted adjacent to or near large-fruited tomatoes,
they may serve as a reservoir for the shorter-termed tomato crop.
Another change that ipp I r-,:. is still developing, is the ability of
the SLWF to colonize pepper. Ten years ago, whitefly adults could be
found on pepper plants, but there was little or no reproduction on the
crop. As a result, pepper was not a reservoir of I rctil.c for tomato
(Schuster et al. 1992). Today, whitefly nymphs are routinely observed in
large numbers on pepper, which is a longer term crop than tomato. In
addition, some pepper cultivars are susceptible to TYLCV (Polston
unpublished data). Therefore, pepper might be serving more now than
before as a source of' Inr-ctel and TYLCV especially to bridge the fall
and spring crops.

New Products for the Future
In an experiment conducted during the spring of 2002 at GCREC, a
single application of MT-02-03, which is now revealed as Oberon
(spiromesifen; Bayer CropScience, Kansas City, MO), resulted in num-
bers of SLWF nymphs below the threshold of 5/10 leaflets for up to four
weeks (Schuster et al. 2002). Four applications of Diamond (novaluron;
Crompton Uniroyal, Raleigh, NC) also reduced nymph numbers below
the threshold. Additional experiments have been conducted during the
fall of 2002 and spring of 2003.
In the fall 2002 experiment, Oberon 240SC (8.5 ozs/acre) was

applied, following an at transplant application of Admire at 16 ozs/acre,
when the threshold of 5 nymphs/10 leaflets was reached. The treatment
was compared to Admire alone, to Admire followed by a weekly alterna-
tion of Baythroid 2 (2.8 ozs/acre) and Thiodan 50W (2 lbs/acre), or to a
check. Control of whitefly nymphs with either Oberon or the weekly
alternation of Baythroid and Thiodan were equivalent and 'i._., iidnri,
lower than the check; however, Oberon was applied twice while
Baythroid and Thiodan were each applied five times (Fig. 4). Both treat-
ments resulted in densities of SLWF nymphs below the threshold for five
weeks, while densities in the check plots were above the threshold.
In the 2003 experiment, Diamond 0.83E (14.5 ozs/acre), Oberon
240SC (8.5 ozs/acre) or Courier 70W (0.5 lb/acre) were applied follow-
ing an at-transplant application of Admire (16 ozs/acre), when the thresh-
old of 5 nymphs/10 leaflets was reached, and were compared to Admire
alone or to a check. A single application of Oberon reduced nymphal
numbers to the threshold or below for at least two weeks. A single appli-
cation of either Diamond or Courier resulted in significant reductions in
the numbers of nymphs compared to the check within one week of the
application. Further evaluations were precluded by the effects of heavy
rains on the tomato foliage.
The high level of some RS50 values, especially in 2003, suggests a
decline in the susceptibility of the SLWF to Admire; however, the appar-
ent shift in susceptibility may be as much a reflection of changes in crop-
ping practices and nicotinoid use patterns as a true trend in declining sus-
ceptibility. Furthermore, the reduced susceptibility appears to be unstable
when Ih at-11 ic are no longer exposed to Admire. Therefore, lengthening
a tomato free period in the summer to at least two months and making
only a single application of a nicotinoid insecticide could help in manag-
ing the reduced susceptibility.
The high numbers of whitefly adults observed this past spring could
be related to the reduced susceptibility of the SLWF to Admire, but this
is probably not the whole answer. A shortened tomato-free period in the
summer caused by economic concerns and increased acreage of grape
tomatoes, and changes in suitability of pepper as a whitefly reservoir
undoubtedly also have contributed. Although there are new products on
the horizon for managing the SLWF, growers are encouraged to redouble
their efforts in implementing a nicotinoid resistance management pro-
gram that was first* irl i-icd by Schuster and Thompson (2001).

Nicotinoid Resistance Management Recommendations
*Reduce overall whitefly populations by strictly adhering to cultural
practices including:
-Plant whitefly-free transplants;
-Delay planting new crops as long as possible and destroy old
crops immediately after harvest to create or lengthen a toma-
to-free period;
-Do not plant new crops near or adjacent to infested weeds or
crops, abandoned fields awaiting destruction or areas with
volunteer plants;
-Use UV-reflective (aluminum) plastic soil mulch;
-Control weeds on field edges if scouting indicates hI~ ri-tl
are present and natural enemies are absent;
-Manage weeds within crops to minimize interference with
spraying; and
-Avoid u-pick or post harvest pin-hooking operations unless
effective control measures are continued.
*Do not use a nicotinoid like Admire on transplants or apply only
once 7-10 days before transplanting; use other products in other
chemical classes, including Fulfill, before this time
*Apply a nicotinoid like Admire (16 ozs/acre) or Platinum
(8ozs/acre) at transplanting and use products of other chemical
classes (such as the insect growth regulators Knack (pyriproxyfen;
Valent U.S.A. Corporation, Walnut Creek, CA) or Courier (bupro-
fezin; Nichino America, Inc., Wilmington, DE) as the control with

the nicotinoid diminishes.
*Never follow an application (soil or foliar) of a nicotinoid with
another application (soil or foliar) of the same or J.tici-a r ...i. ........i
on the same crop or in the same field within the same season (i.e. do
not treat a double crop with a nicotinoid if the main crop had been
treated previously).
*Save applications of nicotinoids for crops threatened by whitefly-
transmitted plant viruses or whitefly-inflicted disorders (i.e. tomato,
beans or squash) and consider the use of chemicals of other classes
for whitefly control on other crops.

The authors wish to express their appreciation to Emily Vasquez and
Steve Kalb for their technical assistance. The authors also thank Bayer
CropScience for their support of the resistance monitoring efforts for

References Cited
Elbert, A. and R. Nauen. 2000. Resistance in Bemisia tabaci
(Homoptera: Aleyrodidae) to insecticides in southern Spain with special
reference to neonicotinoids. Pest Management Sci. 56:60-64.

SAS Institute Inc. 1989. SAS/STAT User's Guide, Version 6, Fourth
Edition, Bol. E, SAS Institute Inc., Cary, NC.

Schuster, D. J. 2002. Action threshold for applying insect growth regu-
lators to tomato for management of irregular ripening caused by
Bemisia ,.- i. t. .. (Homoptera: Aleyrodidae). J. Econ. Entomol.

Schuster, D. J. And S. Thompson. 2001. Monitoring susceptibility of the
silverleaf whitefly to imidacloprid, pp. 16-18. In P. Gilreath and C. S.
Vavrina [eds.], 2001 Florida Tomato Institute Proceedings, Univ. Fla.,
Gainesville, PRO 518.

Schuster, D. J., J. E. Polston and J. F. Price. 1992. Reservoirs of the
sweetpotato whitefly for tomatoes in west-central Florida. Proc. Fla.
State Hort. Soc. 105:311-314.

Schuster, D. J., P. A. Stansly and J. E. Polston. 1996. Expressions of
plant damage by Bemisia, pp. 153-165. In D. Gerling and R. T. Mayer
[eds.], Bemisia 1995: Taxonomy, Damage, Control and Management.
Intercept Ltd., Andover, Hants, United Kingdom.

Schuster, D. J., S. Thompson, P. A. Stansly and J. Conner. 2002. Update
on insecticides for whitefly and leafminer control, pp. 51-60. In P.
Gilreath and C. S. Vavrina [eds.], 2002 Fla. Tomato Institute Proc.,
Univ. Fla., PRO 519.

Stansly, P. A., D. J. Schuster and G. L. Leibee. 1991. Management
strategies for the sweetpotato whitefly, pp. 20-43. In C. S. Vavrina [ed.],
Proc. Fla. Tomato Institute 1991, Univ. Fla., Gainesville, SS-VEC-01.

Table 1. Relative susceptibility (RS5o) of silverleaf whitefly adults to Admire in the laboratory using a cut leaf
petiole method. Adults were reared from nymph-infested foliage collected from tomato fields treated with
Admire at transplanting.

County/Site Date RSsol

Hendry/Devil's Garden April 3.1
Collier/Immokaleel, Field 2 May 14.6
Collier/Immokalee2 May 5.1
Manatee/Duette June 8.0
Hillsborough/Ruskin June 4.6
Manatee/Ft. Hamer June 13.1
Manatee/GCREC, Field June 2.6
Hillsborough/Riverview July 4.5
Manatee/Myakka City Dec 4.7
Collier/Immokaleel, Field 1 April 7.3
Palm Beach/Boynton Beach April 2.6
Collier/Immokalee3 April 5.6
Collier/Immokalee4 April 2.9
Collier/Immokaleel, Field 2 May 3.9
Dade/Homestead May 7.3
Collier/SWFREC May 21.9
Manatee/Duette June 35.2
Manatee/Ft. Hamer June 5.7
Hillsborough/Ruskin June 3.4
Manatee/GCREC, Field 1 June 14.8
Manatee/GCREC, Field 2 June 5.9
Manatee/Lorraine June 1.2
Manatee/Parrish Nov 21.0
Collier/Immokalee2 May 12.1
Hillsborough/Ruskinl June 19.2
Hillsborough/Ruskin2 June 7.0
Manatee/Duette June 14.8
Manatee/Ft. Hamer June 17.8
Manatee/Lorraine2 June 12.8
Manatee/Lorraine3 June 20.6
Manatee/Myakka City June 3.6
Manatee/Parrish June 21.2
Manatee/Waterbury June 17.4

iRatio of the LC50 of the indicated population to the LC50 of the laboratory colony.
Increasing values greater than one indicate decreasing susceptibility to Admire relative
to the laboratory colony.

Table 2. Three years of monitoring of relative susceptibility (RS50) of whitefly adults to
Admire using a laboratory bioassay.

2001 2002 2003
No. sites 9 14 10
Range 2.6-146 1.2-35.2 3.6-21.2
No. Sites 10 (%) 2 (22) 4(29) 8 (80)
Avg. 6.7 9.9 14.7
No. sites 5 6 9
Range 2.6-13.1 1.2-35.6 3.6-21.2
No. Sites 210 (%) 1(20) 2 (33) 7 (78)
Avg. 6.6 11.0 14.9

Table 3. Changes in relative Admire susceptibility (RS50) of silverleaf
whitefly adults evaluated two to four generations following collection in
the field.


Immokalee 1
Immokalee 1



Collected Evaluated

8 May
6-13 July3

13 June
13 June4

21 May
21 May4

Estimated no.
in lab'

18 May
18 Aug

21 June
16 Aug

31 May
10 July

'One generation in the lab requires about 2 wk.
2Ratio of the LC5o of the field population to the LC50 of the lab colony.
Increasing values greater than one indicate decreasing susceptibility to
Admire relative to the laboratory colony.
3Collected as adults on whitefly-free tomato plants placed in the field
about 4 wk after crop destruction.
4Survivors of the original bioassay were reared on tomato without
selection in the lab for 6-8 wk.





--*--Admire 2F 16 ozs/acre

Platinum 25C 8 ozs/acre Duette


I" I
M /

-- _' I *

* a.........

- +- Admire 2F 16 ozsacre
- -a- Platinum 25C 8 ozsfacre
- &-- Control




S-l ,

3 4 5 6 7 8 9 10 11 12

Weeks after transplant

Fig 1. Control of silverleafwhitefly nymphs with soil applications of
nicotinoid insecticides on tomato, Spring 2003. Data points within boxes are
significantly different from the control.


-----Admire 2F 16 ozslacre GCREC
Platinum 25C 8 ozslacre
---- Control


--,- ...

/ ., '


j 30


, 20
5 15



. ..

Sept ct Nv Dec Jan Feb Nar Apr ay Jmn Ady Ag
Fig. 2. Generalized depiction of the susceptibility of whitefly
adults to Admire.

Aug Sept Oct Nov Dec Jan Feb Mar Apr May Jun July Aug Sept

Fig. 3. Generalized depiction of relative, seasonal tomato
acreage in west central Florida.

* 30

(1 20
E 15

6 10



4 5 6 7 8 9 10 11 13

Weeks after transplanting

Fig 5. Control of silverleaf whitefly nymphs on tomato with soil and foliar
applications of insecticides, GCREC, Spring 2003. Admire was applied at
transplanting. Oberon was applied during week 10 and 12 and Diamond and
Courier were applied during week 12. Data points within boxes are significantly
different from the control.

--&-- Admire 2F then Oberon 240SC + Induce
--A -Adnire 2F then Baythroid 2 or Thiodan 50W
----- Control


S- -- ......... ........ 4- -1 .. A....

9 10 11 12 13 14 15 16 17

Weeks after transplanting

Fig 4. Control of silverleaf whitefly nymphs on tomato with soil and foliar
applications of insecticide, GCREC, Fall 2002. Admire applied at
transplanting. Applications of Baythroid and Thiodan were alternated weekly
beginning 3 weeks after transplanting. Oberon was applied during week 12 and
13. Data points within boxes are significantly different from the control.









Tomato Disease Update

Pam Robertsl, Tom Kucharek2, Phyllis Gilreath3,
Henry Yonce4, Jeff Jones2, and Gene McAvoy5.
1SWFREC, Immokalee, 2Plant Pathology Department,
Gainesville, 3Manatee County Extension Office, Palmetto,
4KAC Agricultural Research, Inc, DeLand, 5Hendry County
Extension Service, LaBelle

Significant outbreaks of several diseases on tomato occurred in
recent seasons. Gray Mold, caused by the fungus Botrytis cinerea, his-
torically occurred quite commonly in Ft. Pierce, FL area in the early
1960s and was detected this spring, 2003, in the Manatee production
region. White mold, caused by the fungus Sclerotinia sclerotiorum, was
widespread on tomato and pepper in south Florida in the same season. A
new race 4 of bacterial spot on tomato, caused by the bacterium
Xanthomonas campestris pv. vesictoria, was identified. An aerial blight
on tomato seedlings caused by Pythium myriolotium has been described.
Specific information on each disease is presented.
Epidemics of disease are greatly influenced by environmental con-
ditions. The average temperature in March 2003 was almost 6 degrees
higher than the 30-year average. The average temperatures for April and
May were almost identical for their 30-year averages. However, precipi-
tation was higher compared to the 30-year average in March by almost 2
inches and only slightly higher compared to their 30-year averages in
April and May. However, compared to only the past few years, precipita-
tion in these two months was ...,,it;l l.rii, higher. May 2003 had nearly
4 times as much precipitation as the previous year. The warmer weather
and high rainfall in March and the relatively wet spring undoubtedly con-
tributed to some of the atypical plant problems that were encountered.

Gray Mold (Botrytis cinerea)
An outbreak of gray mold on tomato was recorded in May 2003 that
was widespread in the Manatee area. Several varieties of tomato, includ-
ing rounds, roma, and grapes, were affected. Lesions on the foliage such
as blighting were difficult to distinguish from other types of damage.
However, the fungus was found associated with leaflets that wilted and
died. Typical symptoms are V-shaped grayish-brown on the leaves. Stem
lesions are large, elliptical, and water-soaked and also turn grayish-tan.
The most significant damage occurred on the blossoms, which turned
brown and became covered with the sporulating fungus. Tomato fruit
showed typical soft rot symptoms with the soft center and expanding,
watersoaked lesion. Under certain environmental conditions, a lesion that
is a lightly-colored, circular ring called Ghost Spot occurs although this
symptom was not evident in these outbreaks. In some fields surveyed,
every plant that was inspected had infected blossoms and foliage with
symptoms of gray mold.
Botrytis cinerea has a very wide host range so its presence on any
one of many Ji tt!i i ir plants could be the source of the initial inoculum.
The fungus may also survive from season to season as a sclerotium (plu-
ral: sclerotia), an environmentally resistant fungal survival structure. In
addition, it can survive saprophytically on plant debris in the soil.
Therefore, there is no shortage of potential sources of inocula and means
of survival for this pathogen.
The fungus is considered weakly pathogenic and initial infection is
usually associated with wounded plant tissue. On the foliage, mature
plants with a thick canopy will first show symptoms on the older tissue
and then move onto younger tissue. Spores of the fungus, called conidia,
are readily produced and easily windblown to new infection sites.
Moderate weather in the mid-70s F favors production of conidia. The
humidity within a mature tomato canopy is sufficient for disease devel-
opment. Warmer weather may slow this disease. Gray mold is most
severe on plants grown in acidic, sandy soils with high soil moisture.

The presence of the fungus should be confirmed prior to any control
measures because its symptoms ;i c d itt tI ir r, i.li.iiiiinJi ti, ini other dis-
ease and abiotic problems. Applications of labeled fungicides may aid in
control. Adequate calcium should be available to plants. Acidic soils
should be limed and uniform soil moisture should be maintained through-
out the season for maximum calcium availability to the plant. A calcium-
to-phosphorus ratio of 2 or higher in leaf petiole tissue has been demon-
strated to aid in control.

White Mold (Sclerotinia sclerotiorum)
White mold was widely reported on tomato, pepper, eggplant, and
bean in south Florida beginning in January 2003 and continuing through-
out the rest of the spring growing season.
Like gray mold, the fungus that causes white mold has an extensive
host range and is an economically important disease on many vegetable
crops. In tomato, symptoms typically occur at flowering and begin as
water-soaked lesions in leaf axils or stem joints where fallen flower petals
collect. The stem becomes infected at this point and initially the tissue is
soft but will die and become hardened and bleached. The black sclerotia
are often found inside of the dead, infected stems. The presence of the
small, black sclerotia is a sign of the fungus and is diagnostic for this dis-
ease. Another sign of the fungus is a white, cottony mycelium that is fre-
quently present on diseased tissue. Because other pathogenic fungi pro-
duce white mycelia, this character, by itself, should not be relied upon for
diagnosis in the field.
Overseasoning of the fungus is by sclerotia, which are also the
source of initial inoculum. Sclerotia may be moved via irrigation water.
The sclerotia germinate under cool (average 65 F) and wet environmen-
tal conditions and produce a type of spore, called an ascospore, that is
carried by wind currents to the host tissue. The fungus becomes estab-
lished initially on senescent tissue and can then colonizes adjacent
li, il i:. r n,, Long periods of continuous wetness (16-72 h) are required
for infection.
Management options for control of white mold are limited. Although
some research suggests that flooding or addition of organic soil amend-
ments may suppress the disease, these options may not be practical or
provide sufficient control. Fumigation of the soil and plastic mulch help
to reduce the viability and eliminate direct contact of host tissue with
sclerotia. A Section 18 (FIFRA) was recently granted for use of Topsin M
fungicide in Florida for control of this disease on fruiting vegetables
including tomatoes and is effective from July 3, 2003 to March 31, 2004.

Bacterial Spot, Race 4 (Xanthomonas campestris pv. vesicatoria)
Over the past couple of years, we received samples of bacterial spot
disease of tomato from several locations. Isolations from the samples
revealed the typical bacterial spot organism. Tomato race determinations
were done on tomato Ji.!!t t c iIt. The strains behaved like tomato race
2 (T2) strains rather than T1 or T3, both of which are normally present in
Florida. This would be an unusual occurrence since T2 has never been
detected in Florida. With the possibility of these strains being T2, the
strains were then characterized using a genetic technique that J, itic !c-.ir-
ates T1, T2 and T3 strains. The new strains resembled typical T3 strains
based on this technique. To further substantiate that this was a variant of
T3, the tomato genotype, LA716 (Lycopersicon pinnellii), which contains
a resistant gene that interacts with a gene (avrXv4) present in T3 strains,
was inoculated with the new strains. This resulted in an incompatible
(non-disease) reaction, which confirmed that the new strains were mutant
T3 strains rather than T2. This new race is designated T4. The importance
of this new race is not known.

Aerial Blight of Tomato Transplants (Pythium myriotylum)
An unusual disease outbreak involving an aerial infection of the typ-
ically soil-borne Pythium myriotylum was observed during the fall grow-
ing seasons of September 1996 and 1997, within commercial fields in
Southwest Florida (Collier and Lee Counties) and West Central Florida

(Manatee County). The percentage of plants affected, or plant incidence,
was approximately 15-18% about four weeks after transplanting. The dis-
ease was present mostly on young seedlings during an unusually high
rainfall period.
Symptoms of the disease on tomato seedlings included aerial watery
rots in leaves, petioles, and stems sometimes followed by plant death.
Microscopic examination of symptomatic tissue revealed the presence of
mycelia and oogonia typical of Pythium spp. Pythium myriotylum
Drechsler was ..... icrii, isolated from four plants sampled from each
site. The rainfall recorded at some sites, such as in Manatee Co. in Sept
1997, was 36% higher than the 40-year average. This high moisture situ-
ation likely contributed to the incidence of this foliar blight in tomato
which has not been described previously.
Pythium myriotylum is a commonly found soil-inhabitant and is one
of the most common species of Pythium causing damping-off of
seedlings of many plant species in Florida. Pythium myriotylum is capa-
ble of producing motile spores, called zoospores, and oospores which are
capable of surviving in soil and on crop debris from season to season. It
does well under high temperatures ranging between 86 and 98 F and high
soil moisture. The host range for Pythium spp. is extremely wide includ-
ing most vegetables. Many species of weeds are hosts to Pythium spp.
and serve as important sources of inocula.
Although outbreaks of this disease occurred in two consecutive
years, only one additional outbreak was detected in subsequent seasons.
However, if not detected during the water-soaking phase of the symp-
toms, it could be easily confused with other damping off or blight symp-
toms caused by other pathogens. Fumigation of the soil and fungicide
applications to control damping-off may help to suppress populations of
Pythium myriotylum. Also, one should use fields that drain well.

Additional information and photographs of many tomato diseases
and diseases on other vegetable crops can be found at the following web

Vegetable Disease Fact Sheets:
]lrTp pi 11.p 11i it i, i-l C.ii/takextpub/FactSheets/pppvegetables.htm

Florida Tomato Scouting Guide:
I rTp tT, t it i t1 c 1iii 1 '. J I, rii

Tomato Herbicides: What we have gained,

What We Have Lost and Possible Future


William M. Stall
UF/IFAS, Horticultural Sciences Department, Gainesville

What We Have Gained
Several new herbicides have become available for use in tomato
production. Research is still ongoing on their best use in a weed manage-
ment system. Growers should check their individual labels for all instruc-
tions before use.
Matrix (rimsulfuron). Dupont has issued a supplemental label for
the use of Matrix on fresh market tomatoes. At the present time, the pre-
emergence application is for seeded tomatoes. We are working with
Dupont to add a pretransplant statement. Matrix may be applied both pre-
emergence and postemergence to tomatoes and weeds at 1-2 oz product
(0.25-0.5 oz ai) in single or sequential applications. For POST (weed)
applications, a non-ionic surfactant is required. Matrix may also be
applied to row middles.
Sandea (halosufluron). Gowan has labeled Sandea for use in sev-
eral vegetables including tomatoes. A total of two applications of Sandea
may be applied as either one pre-transplant soil surface treatment at 0.5-
0.75 oz product; one over-the-top application 14 days after transplanting
at 0.5-0.75 oz product; a pre-transplant plus an over-the-top or a POST
followed by a POST application of up to 0.75 oz product. Row middle
applications may be made at up to 1 oz product. A non-ionic surfactant
must be used with POST applications.
Dual Magnum (S-metolachlor). Syngenta has labeled Dual
Magnum to be applied preplant non-incorporated to the top of pressed
beds as the last step prior to laying plastic. It is also labeled for use in row
middles. The rates labeled are 1.0 to 1.33 pints per acre if the organic
matter is less than 3%. Research has indicated that the 1.33 pt rate may
be too high in some Florida soils except in row middles. Good results
have been seen at 0.6 to 1.0 pints especially in tank mix situation under
Goal (oxyfluorfen). Dow has labeled Goal for use as a fallow-bed
treatment in several crops. Goal should be applied as surface treatment to
preformed beds at 1-2 pints/A product. A 30 day treatment to planting
interval must be maintained. Mulch may be applied any time during the
30 day interval.
Aim (carfentrazone). Aim is a broadleaf burdown herbicide from
FMC that has a Section 18 label for postemergence control of emerged
weeds in row middles. It is particularly effective on the control of
paraquat resistant American black nightshade. The use rate is 1 to 2 fl oz
product per acre. To control grasses, it must be tank mixed.

What We Have Lost
Two labels have been lost for use in tomatoes since last year. For
vegetables in general, there have been several products lost. These are
mostly older, seldom used products that had to be incorporated. For toma-
toes the labels lost were:
Tillam (pebulate). Pebulate was scheduled for re-registration. No
company registered the product for 2003 and the federal registration was
Boa (paraquat). Griffin decided to discontinue the Boa label.
Paraquat is still available on tomatoes under the Gramoxone labels. The
affect of the label loss will be more acute in vegetables other than toma-
toes where Boa had a burdown label while Gramoxone does not. The pre
and row-middle labels, as well as the burn down after final harvest, is still
on the Gramaxone labels.

Possible Future Labels
There are a number of herbicides for which residue studies are being
carried out in the IR-4 program. Potential labels for some of these may be
less than a year to several years away. These are being listed for infor-
mation purposes. They are:
Cobra (lactofen). Residue studies are being done for a Florida state
label only. Cobra has both preemergence and postemergence activity of
many broadleaf weeds in row middles, especially nightshade. There was
a Section 18 label for Cobra several years ago, which was lost when the
whole herbicide class chemistry came under review by EPA. Valent will
petition EPA for a state label when the studies are completed and
Valor (flumioxazin). Residue studies are being carried out national-
ly for tomato, pepper and eggplant row-middle application. Valor has
both preemergence and postemergence activity on many broadleaf
weeds. Two years of study in row middles in south Florida has shown that
Valor has excellent safety and the widest range of weed control of any of
the herbicides tested. A national label probably won't be available for
several years.
Envoke (trifloxysulfuron). The tolerance packaged for tomatoes
has been submitted to EPA with possible tolerance establishment this
year. Envoke is an excellent nutsedge herbicide, with control of many
broadleaf weeds applied POST. The potential label will probably be a
post-directed application to established tomatoes.
Spartan (sulfentrazone). Efficacy studies have established that
tomatoes and pepper are tolerant to applications of Spartan under mulch.
Also, Spartan controls nutsedges pre to a great extent and has good con-
trol of many broadleaf weeds in Florida. Spartan cannot be registered in
Florida until the soil dissipation studies submitted by FMC are reviewed
by EPA.
Goal (oxyfluorfen). Pretransplant residue studies are underway in
pepper with tomato to follow for reducing the preplant restrictions from
30 days to probably 5 days.

Weed Hosts, Field Distribution, and
Sampling Strategies for Root-Knot

J.W. Noling1, J.P. Gilreath2, and P. R.Gilreath3
UF IFAS, lCitrus Research & Education Center, Lake Alfred,
2Gulf Coast Research & Education Center Bradenton, 3Manatee
County Cooperative Extension Service, Palmetto

Since 1994, there has been a considerable amount of field research
conducted by University of Florida faculty to identify and evaluate alter-
natives to methyl bromide for soilbome pest and disease control. In our
efforts to define alternatives to methyl bromide, we have observed how
inconsistent and/or ineffective some pest management tactics can be for
weed control, or how others after repeated use can select for resistant
populations rendering the treatment ineffective. We have also observed
how a single herbicide in the mix of pest management alternatives can
provide no assurance for control of all grass and broadleaf weeds present
in the field. As a result of these observations, our projection for the future
and working research hypothesis is that weed density, species diversity,
and the number of problematic fields will increase as we come to rely on
less -i... 'ci ,- i'. effective, narrower spectrum, weed control measures.
Anticipating a future increase in weed pressures and problems, we
began to question what other impacts besides the direct effects of com-
petition for light, water, and nutrients weeds might have on crop growth.
For example, we have observed how failure to adequately manage weeds
within the field can not only affect crop yield, but serve as alternative
hosts to nematodes, causing potential for additional crop production
problems. A number of weeds have also been recently demonstrated in
Florida studies to be excellent hosts to various soilborne disease
pathogens. For example, a pathology review of the common weed, black
nightshade (Solanum nigrum), shows that many of the most importance
soilbome fungal, bacterial, and viral diseases of Florida vegetables are
not only hosted by but are .;,;Fi In ,1ri :. increased by this common weed
species in the field (Table 1). The first part of this article thus describes a
joint research program, funded by the Florida Fruit & Vegetable Research
Foundation, the objectives of which were to 1) characterize the host sta-
tus of various weeds to root-knot nematode from commercial fields ; and
2) to evaluate field level impacts of weed growth on soil population den-
sity of root-knot nematode.
As a result of the expected higher incidence and severity of disease,
weed, and nematode problems in the field, continued development of
IPM strategies which include 1) guidelines for pest scouting / monitoring
; 2) crop loss assessment; and 3) decisions aids to minimize potential pest
induced crop yield impacts are needed. As such, the second part of this
article describes another project funded by the Florida Fruit & Vegetable
Research Foundation, the objective of which was to develop and evalu-
ate a grower conducted, field sampling protocol for root-knot nematodes
using crop plants and root galling indices, rather than soil sampling, as a
means of monitoring nematode populations in cropped fields.

Weed Hosts of Root-Knot Nematode
During 2002, comprehensive field surveys of eight commercial veg-
etable fields were conducted in east, southwest, and west-central Florida
to evaluate the host status of various weeds to root-knot nematode
(Meloidogyne spp.). Weed roots were collected from each field and
returned to the laboratory where the weeds were identified and then
stained with Phyloxine B to 'light-up' the egg masses of the root-knot
nematode adhering to roots. The relative density of egg masses per gram
of weed root was characterized according to an indexing scale of 0 = no
egg masses; 1 light or <10 per gram of root; 2 = moderate or 10-50 /
gram root; 3 = heavy or 50-100 /gram root; and 4 = very heavy or >100
egg masses per gram of root. Simultaneous to the root staining operation,

a subsample of aggregate weed roots was forwarded to the Florida
Department of Agriculture and Consumer Services, Division of Plant
Industry, for extraction and recovery of adult females for DNA finger-
printing and root-knot nematode species identification. Concurrent to the
above studies, grower field demonstration experiments, consisting of
treatments which manipulate weed densities into broad categories
between high and low, were conducted to demonstrate the importance
and direct linkage of weed density and management to nematode popula-
tion suppression.
Results: In six of the eight fields surveyed, Meloidogyne incognita
was the exclusive root-knot nematode species recovered from weed roots.
A new root-knot nematode species, Meloidogyne mayaguensis, was
recovered from one of the seven field sites. In a Myakka City, FL field
location, a mixed population of M incognita and M. javanica were recov-
ered from weed root samples, while a field in Immokalee contained a
mixed population of M incognita and M. arenaria.
Fifteen weeds commonly found in the sandy soils of south Florida
were evaluated for host suitability to root-knot nematode. In general,
nematode galling and egg production was observed on the roots of all fif-
teen weed species from at least one of the seven field survey sites (Table
2). With some weed species such as ragweed, cudweed or goosegrass,
root-knot nematode galling and egg production was variable between sur-
vey site locations and was not correlated with .,ittc!!-c ,- in nematode
species. Six of the fifteen weeds species supported only low to interme-
diate levels of root-knot nematode reproduction at most sites. These
included common ragweed, goosegrass, crabgrass, cudweed, and yellow
nutsedge. Yellow nutsedge was not recovered from the nematode infest-
ed areas of all field survey sites. Nematode galling and egg production
was highest and most efficient on various pigweed (Fig. 1) and night-
shade (Fig. 2) species, common purslane (Fig. 3), clover, Sesbania, sand
vetch, and carolina geranium. Although weed densities were not quanti-
fied at each field survey site, weed densities were typically very high, and
in most cases, provided complete ground cover in areas between raised
beds, the row middles (Fig. 4).
Once the discovery was made that the weed host range for root-knot
nematode was so broad, we decided to begin quantifying the impact of
weeds on nematode population growth in commercial fields. For this
experiment, five treatments were evaluated in a nematode infested pep-
per field in Immokalee, Florida. Two of the treatments included mulch
covered rows which were either 1) in-row fumigated with methyl bro-
mide chloropicrin 67/33 (350 lb/a) or 2) received no fumigant treatment.
The remaining treatments represent the impact of i t- !L c r cultural prac-
tices on weed growth in the row middles. The cultural practices or treat-
ments included 3) row middles receiving pretransplant soil applications
of glyphosate; 4) middles which were twice rotovated for early season
weed control; and 5) middles in which a tightly woven, polypropylene
nursery ground cloth fabric was installed to totally exclude weed growth
in the row middles. At two other commercial field sites, rotovation of row
middles was not included as a treatment for field evaluation. All treat-
ments were initiated at the beginning of the cropping season and nema-
tode samples collected at the end of the growing season after final pepper
As expected, methyl bromide i. ifL o; l':. reduced but did not erad-
icate soil population density of root-knot nematode, and soil populations
were near equivalent to those in the row middles receiving pretransplant
glyphosate treatment (Fig. 5). At seasons end, weed growth in the
glyphosate treated middles consisted of a near complete ground cover of
various grasses, the most important of which was goosegrass and crab-
grass. Root-knot soil populations built to their highest levels on peppers
in the nonfumigated mulched covered beds, and on weeds in the rotovat-
ed middles. Weed densities were highest and most diverse in the rotovat-
ed middles, consisting of a complete 100% ground cover of various
grasses and broadleaf weed species. No nematodes were recovered from
soil below the ground cloth where no weeds were permitted to grow. In
two other field studies, high density of weeds growing in the row middles

. i.;i fi i:. increased root-knot nematode soil population density com-
pared to weed free middles of ground cloth treatments (Figs. 6 & 7), and
in one study, in comparison to fumigant treatments with methyl bromide
or Telone C35.

Research Summary
* The weed host range of root-knot nematode is extremely broad
(Table 2), and nematode population growth is functionally related to the
density, diversity, and root biomass of the weed species present in a field.
* Nematodes cannot be effectively managed unless weeds are also
effectively and simultaneously managed in the field. Weeds which are
allowed to grow and increase in numbers, particularly in-between mulch
covered rows, serve to increase soil population densities of nematodes
and perpetuate the nematode and quite possibly, disease problems from
one cropping season to the next.
* Unmanaged weed growth can have a very destabilizing effect on
pest populations and crop loss. It's not enough that weeds in themselves
reduce crop growth, but they also serve to increase other pest densities
which can even further limit crop growth and yield, and at the same time
make overall pest management more difficult and costly.
Given the extent to which nematode population density increased in
the presence of weeds in the row middles, we would ask growers to pon-
der the consequence and potential impact of such an effect. In the ground
cloth experiment, nematode densities were nearly twice as high in the
middles than in the fumigated, plastic mulch covered plant rows.
Irrespective of what kind of pest control is achieved in the fumigated bed,
when the season is over and mulch removed, the soil from all areas will
be mixed by disking operations which follow. It is not inconceivable to
easily produce doubling or even tripling effects to overall nematode and
disease population levels when weeds are allowed to grow and increase
pest population levels in the row middles (Fig. 8). One might even con-
clude that much of the need for soil fumigation may be predicated on the
impacts weeds have on increasing and preserving soilbome pest popula-
tions at high levels at seasons end, or put another way, mandate the con-
tinued need for broad spectrum soil fumigants for nematode control. To
account for potential interactions involving root-knot nematode, growers
may well be advised to consider more suppressive weed management tac-
tics and strategies for vegetable fields infested with the root-knot nema-
tode. These results also should serve to reinforce our appreciation for
truly integrating IPM practices.

Nematode Sampling Strategies
As indicated previously, various species of the root-knot nematode
(N IL I. .-,.- ." I are some of the most economically important nematode
pests of field grown vegetables in Florida. In order to determine whether
nematodes such as root-knot are the cause for poor crop performance or
to determine the need for nematode management, some form of pest
monitoring or sampling is required. Historically, laboratory assays of soil
samples have been the principal method of detection and quantification
of nematode density. Current methods of soil analysis can be accurate if
sufficient numbers of representative soil cores and samples are removed
from the field for the analysis. Regardless of sampling strategy, increased
precision of the sample estimate can only be achieved with increased
samples which translates to increased time and grower cost.
Due to the field patchiness (clumps) and low abundance of nema-
todes (a microscopic organism) in followed disturbed soil prior to plant-
ing, there is oftentimes no assurance of obtaining accurate estimates of
field populations even with detailed sampling schemes, especially when
large fields are involved. C'!!n-iin the recommendation is to collect a
single soil sample of twenty soil cores representing no more than 10 acres
for relatively low value crops and no more than 5 acres for high value
crops. The sample must also be collected well in advance of planting to
insure time for processing and possible implementation of an appropriate
management practice. Unfortunately, the lengthy time lags from sample

collection to reporting often encourages wary growers, who oftentimes
must act quickly, to adopt inappropriate nematode management strategies.

Use of Plants as Biolndicators of Nematode Problems
Recognizing that the root-knot nematode causes the formation of
large swollen areas or galls on the root systems of susceptible crops, rel-
ative population levels and field distribution of this nematode can be
largely determined by simple examination of the crop root system for root
gall severity. Root gall severity is a simple measure of the proportion of
the root system which is galled. Immediately after final harvest, a suffi-
cient number of plants could be carefully removed from soil and exam-
ined to characterize the nature and extent of the problem within the field.
In general, soil population levels increase in an exponential fashion with
root gall severity. This form of sampling can in many cases provide
immediate confirmation of a nematode problem and allows mapping of
current field infestation. Cm l-nd:. the detection of any level of root
galling usually suggests a nematode problem for planting a susceptible
crop, particularly within the immediate areas from which the galled
plants) were recovered. The purpose of these studies was therefore to
explore the use of root galling, rather than soil sampling, as a means of
monitoring nematode populations in cropped fields.
Procedure. Eight fields in which crop production problems involv-
ing root-knot nematode Ihil-I...l.-. ,,- sp.) were identified in the veg-
etable producing areas of west central and southwest Florida. In each of
these fields, root-knot nematode infestation levels and patterns of field
distribution were characterized by removing infested plants from mulch
covered rows, acquired systematically from across each growers field
after final harvest of the primary crop. At two sites, some of the excavat-
ed plants were individually weighed and root gall severity ratings record-
ed. The study area at each site consisted of a 3-4 acre subsection of infest-
ed field. The basic sampling unit within each field consisted of blocks of
6 plant rows (spray rows). In each 3 4 acre subsection, upwards of 500
crop plants were removed from the soil after final harvest. Plant removal
followed a regular / systematic pattern of 50 foot increments within each
plant row (Fig. 9). The actual number of plant samples removed was
defined by row length and the number of rows within the 3-4 acre field
site. Once uprooted, the specific field location (block, row, section) and
root gall severity index value were recorded. The root galling index used
consisted of a scale of 0 to 10, reflecting the proportion of root system
galled (Fig. 10). Grower field personnel who participated in these studies
were field trained and continually coached for all plant and root system
rating evaluations.
Upon return to the laboratory, the data was entered to computer in
spreadsheet format for statistical, simulation, and graphical analysis.
Probabilities of detecting root-knot nematode infested plants focii) for a
range of sample sizes was computed for each 6 row block within each
nematode infested field surveyed. Sample sizes were also computed and
correlated with the range of field infestation level within blocks and
fields. As indicated previously, the objective was to determine the small-
est number of plant samples (how many) which maintain sampling error
within acceptable limits. To minimize sample requirements, frequency
distributions were also calculated and analyzed for specific sample site
locations to identify any propensity for root-knot nematode infestation to
specifically occur within certain areas of the field. This analysis was con-
ducted to determine whether it might prove useful for instructing grow-
ers where to sample, i.e., within certain rows, blocks, subsections.
Results. Preliminary analysis of patterns of field distribution of
root-knot nematode indicates a nonrandom, aggregated pattern of field
distribution in most of the fields surveyed (Fig. 11). These same analyses
also suggest that the crowned areas of the field or field center is often-
times the site which recolonizes first with root knot nematode after soil
fumigation.. This early recolonization by root-knot nematode may occur
because these crowned areas are possibly the hottest and driest areas of
field at the time of soil fumigation, and the more rapid escape of the fumi-
gant may afford nematodes greater survival. At other experimental sites,

root-knot nematode recolonization appears to occur along rows rather
than between rows (Fig. 12). Interestingly, sampling precision was gen-
erally less variable, and often required fewer samples when plants were
randomly obtained exclusively from the crowned areas or field middles
rather than from plants acquired randomly throughout the entire field.
Preliminary analysis of these data also indicate that as overall root
gall severity increases in the field, the numbers of plants which must be
uprooted and examined for root galling for a given level of sampling pre-
cision decreases. For a given sample size, sampling precision increased
.;i.,if'in iri:. when overall root gall severity was greater than 5 (scale 0-
10) in any given field. This was fortunate because the visual acuity of
growers to detect the presence of galling on roots also appears to be at or
near a root gall severity index of 5. At this overall level of root galling,
growers must inspect a minimum of 4 to 6 plants per 6 row field block to
achieve acceptable precision. When the nematode problem in the field is
less severe and overall root gall severity less than 5, as many as 2 to 10
more plants must be inspected to accurately assess nematode problems
within the field with the same level of sampling precision.
In summary, these field results and analyses suggest that use of crop
plants as bioindicators of nematode problems can be a meaningful,
informative, and grower acceptable means of nematode sampling. Rather
than soil sampling, the results of these studies suggests that use of root
galling indices of crop plants acquired systematically from grower fields
after final harvest of the crop can be used to accurately characterize root-
knot nematode infestation level and for revealing patterns of field distri-
bution. Work continues to correlate whether root gall severity and foliar
symptoms of plant health could also prove useful for determining which
plants to select for root-knot nematode sampling. Non random sampling
strategies directed at specific field locations and at plants showing
decline symptoms are practical considerations which could improve
detection and quantification of field distribution and nematode density
with least grower cost and resource commitment.

Table 1. Fungal bacterial, and viral disease hosted by black nlihtshade.

4 Weeds as Hosts of Disease
Black Nightshade (Solanum nigrum)

Phytophthora capsici
Phytophthora infestans
Phytophthora nicotiana
Phythium sp.
Rhizoctonia solani
Fusarin oxysporum
Vertiidliumn dahliae
Verticillium albo atrwn
Scderoda rolfii

Colletoricum gleosporoides
Botryis cinerea

E inia carotovora
Psuedomonas solanacearum
Xanth oonas campestris

Tobacco Etch Virus
Tobacco Mosaic Fir

French eIt, 2002; Affleri e 1994; Farr e" 1989

Table 2. Results of Field Survey Demonstrating the Capacity
of Different Weeds to Support Root-Knot Nematode Reproduction
Weed Species: Reproductive Index (range)
O Pigweed Heavy Very Heavy
O Purslane Very Heavy
O Nightshade Few -Very Heavy
0 Eclipta Moderate Heavy
Ragweed None Few
O Clover Very Heavy
O Sesbania Very Heavy
O Sand Vetch Very Heavy
O Goosegrass Few-Very Heavy
Crabgrass None Few
O Carolina Geranium Very Heavy
O Cutleaf Primrose Moderate
Gnaphalium Moderate -
Cudweed None Few
Yellow Nutsedge Few
0 Key Florida Species (Weed Density x Index

Figure 1. Ireay gaJlmg or plgweed rools by root know nem2lode, feleodgyne upp.
.4. W,

*h.l2'f1Y *W 'i !j F - -- V L .Flr L -L -- IE
Fg.2. Heavy piling of black lightshade by root knot nematode, Melodigyne spp.

I FEurr 3. Hegw uofltig or Druionl roots by root knot nemvtpode. Meledleyo. spy. I


Fig. .5 Number ef root-knot n eatues frm row middles, raised plant beds or
below ground cloth cove I nonhmiJgted (check) or sol fumigated actions.
Weed / M1ddles MaImn mentGround Clth Trial Fall 2002

Numbers J2 Meloidogyne / 100 cc Soil

400 aimuted

300 roa
240 Row
l br Bed "

0 -A
Methyl Bromide: Untreated Control

ABftr 1' pepper ecop

Fig 6. Number of roet-kM nematodes ftrI row mIddes, raised pllat b.ed, or
belw ground cloth cover in m.nfumgated (check) or soil fulmgated locatlom.
Weed / Middles Mmuagement Ground Cloth Trial Spring 2003

Numbers J2 Mdeoidogyne / 100 cc Soil
Row Middle
P= 0.019

200 Ground
IMbr C35 Cloth
Bed Bed Middle
10 (0.0) (0.0) (9. )

0 __ I
Final Harvest 1 crop tomato F FF Farms, Sprng 2003

Fig. 7. Number of roet-knt nematodes from row middles, raised plat beds, or
below ground clot cover in mntfiilgated (check) or softly rmigated localtl s.
Weed / Middles Managenmet Ground Cloth Tri Spria 2M3

Numbers J2 Meloidogyne / 100 cc Soil
110 P= 0.0001
100 -

0 -oo


Final Hrvest -2" crop Cuk*e after Tomato. Hendly Co., Spring 2003




Figure 9.

I I S -- 6 \ A

I* ": *: l

---- ---------Drive row / Spray Middle------
I :* *: *: *

I 4 i "I i "b

----------------Drive row / Spray Mid le-------

i I o i o o o oi I

The basic sampling unit: grower define s ray
SSites for removal and gal indexing of a crop pant based
on 50 ft increments of plant row.

,r land

Figure 10.
Rating scheme for evaluation of root-knot Infestation
,1 P1 I





~ ~

*w W, Sll

Figure 11. Spatial distribution of root knot nematode galling on roots of eggplant
in a commercial field.
Contour Plot of gallrat2

11 2


3 -
2 -
0 10 20 30 40 50
Blocks 30 thru 37
22 of 528 plant infested

Figure 12. Spatial distribution of root knot nematode galling on roots of zuchinni in a
commercial field.
NORTH Contour Plot of gallrate
6L'sZuchinni Field -April 2002

0 10 20 30 40 50 60 70

Innovative Approaches for Soil Fumigation

Dan 0 Chellemi' and John Mirusso2
1USDA, ARS, Horticultural Research Laboratory, Fort Pierce,
FL; 2Mirusso Fumigation and Equipment Inc., Delray Beach, FL

New technology and application methods for soil fumigants are
available to the Florida fresh market tomato industry. Growers can
improve the performance of soil fumigants by using these advancements
to take advantage of some key characteristics of fumigants. Examples are
presented that have been supported by results from field trials conducted
in Florida.
Fumigants are volatile materials that form vapors that are toxic to
organisms (1). The effectiveness of a fumigant is a product of its concen-
tration in the soil and the time of exposure (2,3). Most fumigants are
effective against a wide range of organisms, when tested in the laborato-
ry under controlled conditions where they are dispersed evenly through-
out the soil profile (4). In the field, the performance of fumigants is often
variable from site to site or year to year (5,6).
Vapor pressure is one characteristic of fumigants that describes their
ability to move through air spaces in the soil. The greater the vapor pres-
sure, the more easily the fumigant moves through the soil. The water/air
ratio is another characteristic that can be used to describe the movement
of fumigants through soil (7). Water/air ratio takes into account the water
solubility of the fumigant and its concentration in the soil water and the
soil atmosphere (7). As the water/air ratio increases, the ability of a soil
fumigant to move through the soil profile decreases. For example, 1,3-
dichloropropene (1,3-D or Telone) and Lcirii.,i,.rii,.', 11 ir, (metam
sodium or Vapam) have similar vapor pressures but differ in their water
solubility (Table 1). As a result, more 1,3-D remains in soil atmosphere
than in the water phase, allowing it to move through the soil profile more
easily. Compounds with a water/air ratio greater than 100 are not consid-
ered fumigants because they are not volatile enough to disperse uniformly
in the soil (7).
For soil fumigants to be effective they must be given the opportuni-
ty to disperse through the soil profile yet they also must remain in the soil
at a given concentration long enough to become toxic to the pest organ-
ism. In situations where broadcast applications are made, compacting the
soil at the surface to create a barrier will improve the retention of the
fumigant and its performance. In a field trial conducted at the USDA
Header Canal Farm in Fort Pierce, retention of 1,3-D in soil following
broadcast application was measured at daily intervals. Applications were
made in soil that was tilled using a field cultivator and in soil where a
water-filled roller was used to seal the surface. Concentrations of 1,3-D
in the upper 5 inches of the soil profile were similar 24 hours after appli-
cation (Figure 1). However, by 48 hours after application, 1,3-D concen-
trations were noticeably higher where the soil had been sealed, indicating
that more of the fumigant was retained in the soil. In a large scale field
trial of methyl bromide alternatives conducted on a commercial pepper
farm in 2000, several sections of the field were 'I iJ- ci-!r-,ri cultivated
24 hours after a broadcast application of Telone C-35. The resulting inci-
dence of Phytophthora blight in the cultivated sections was 17% at first
harvest, while disease incidence was less than 1% in the noncultivated or
IJ II...l im inri. i bromide fumigated sections (8).
Placing a physical barrier at the soil surface to prevent the escape
(emission) of fumigants into the atmosphere will increase their concen-
tration in the soil and the time of exposure to pests, thus improving their
performance. Polyethylene mulches are highly permeable to soil fumi-
gants and thus marginally effective in preventing emission from fumigat-
ed soil to the atmosphere (9,10). Virtually impermeable films (VIF) pre-
vent emission of fumigants. Several brands have been developed by plas-
tic manufacturers and evaluated in research plots and on commercial
tomato production farms in Florida (11). Use of VIF can have a dramatic

impact on the retention of fumigants in the soil and the resultant control
of key soilborne pests. In a replicated field trial conducted at the USDA
Header Canal Farm, retention of 1,3-D in the upper soil profile was dra-
matically improved under a VIF film when it was injected into the beds
ift1 ri c'. were formed and the VIF applied (Fig. 2).
Allowing the pest organism to become more sensitive to fumigants
(priming) can increase the effectiveness of fumigants. Subjecting pests
to elevated soil temperatures for a short period of time can enhance the
effectiveness of soil fumigants (12). An alternative is to create conditions
that are conducive for germination of growth of pest propagules prior to
fumigating. In field trials conducted at the USDA Header Canal Farm,
control of yellow and purple nutsedge was .;i.L, i .rl -:. improved when
Telone C-35 was injected into the beds 7 days fitr ri ':. were formed and
covered with plastic mulch (Fig. 3).
Prior to 1999, the technology was not available for Florida growers
to broadcast apply fumigants effectively unless soil was freshly disked.
Development of the "Yetter 30 Avenger" (Yetter Equipment Co.,
Colchester, IL) allows growers to fumigate fields without disturbing the
soil surface. Thus, fields can be fumigated ,tr,- ri,:, have been laser lev-
eled but before they have been disked for planting. Prior to 2002, the
technology was not available for growers to fumigate existing plastic-
mulched beds unless they had access to drip irrigation. Development of
the "Mirusso-Chellemi Under Bed Fumigator" provides growers with the
opportunity to apply fumigants under existing plastic-mulched beds or
previously used beds prior to the planting of a double crop. A patent
application was submitted to the United States Patent & Trademark
Office on 3, October, 2002 (Serial No.: 10/263, 107 and Docket No.:
0113.02) for the Under Bed Fumigator.
Many years of research and on-farm trials have resulted in several
alternative chemical programs that can provide control of soilborne pests
equivalent to the standard practice of bed fumigation with methyl bro-
mide. However, all of the alternative options will require increased
knowledge of the history and biology of soilborne pests in individual
fields and more detailed attention to the application technology used for
Mention of a trademark, warranty, proprietary product, or vendor
does not constitute a guarantee by the United States Department of
Agriculture and does not imply its approval to the exclusion of other
products or vendors that may also be suitable.

Literature Cited
1) Ware, G.W. 1978. The Pesticide Book. W.H. Freeman and Co.

2) McKenry, M.V., and Thomason, I.J. 1974. 1,3-dichloropropene and
1,2-dibromoethane compounds: II. Organism-dosage-response stud-
ies in the laboratory with several nematode species. Hilgardia

3) Munnecke, D.E. and S.D. Van Gundy. 1979. Movement of fumigant
in soil, dosage response and Jdt--ciciir effects. Annual Review of
Phytopathology 17:405-429.

4) Baines, R.C., L.J. Klotz, T.A., DeWolfe, R.H., Small, R.H., and
G.O. Turner. 1966. Nematocidal and fungicidal properties of some
soil fumigants. Phytopathology, 56:691-698.

5) Snipes B.S. and D.P. Schmitt. 1996. Control of Rotylenchulus reni-
formis on pineapple with emulsifiable 1,3-dichloropropene. Plant
Disease 80:571-574.

6) Vanachter, A. 1979, In Soil Disinfestation, pp. 163-184. D. Mulder
ed,. Esevier Scientific Publishing Co.).

7) Goring A.I. 1967. Physical aspects of soil in relation to the action
of soil fungicides. Annual Review of Phytopathology, Vol 5, pp.

8) Chellemi, D.O., J. Mirusso, J. Nance, and K. Shuler. 2001. Results
from field demonstration/validation studies of Telone products on
the Florida East Coast. Proc. Fla Tomato Institute. Pp. 50-58.

9) Gan, J., S.R. Yates, D. Wang, and F.F. Ernst. 1998. Effect of appli-
cation methods on 1,3-dichloropropene volatilization from soil
under controlled conditions. Journal of Environmental Quality,

10) Jin, Y. and W.A. Jury. Methyl bromide diffusion and emission
through soil columns under various management techniques.
Journal of Environmental Quality 24:1002-1009.

11) Chellemi, D.O, S.M. Olson, D.J. Mitchell, I. Secker, and R.
McSorley. Adaptation of soil solarization to the integrated manage-
ment of soilborne pests of tomato under humid conditions.
Phytopathology 87:250-258.

12) Eshel, D., A. Gamliel, A. Grinstein, P. Di Primo, and J. Katan. 2000.
Combined soil treatments and sequence of application in improving
the control of soilborne pathogens.


Post fumigation inoculant
for vegetables and citrus
Concentrated liquid suspension culture of
naturally occurring, beneficial, Mycorrhizal fungi

*University validated results. 2003 Florida Tomato crop increase of 1-6 bins/Acre.
Used in California and Mexico since 1995. Now available for the 2004 Florida season.
* Liquid that is easier to apply than currently available alternatives.
* Superior price:performace ratio.
*Available through full service Ag. Chem dealers.

i For information contact: John Olivas, BioScientific, Inc.,
S Ph. 559-269-1152, email: john.olivas@biosci.com

Table 1. Characteristics of selected fumigants (see reference 7).
Chemical name Vapor pressure a Water solubility(%) Water/Airb
Methyl bromide 1380 1.60 4.1
Chloropicrin 20 0.195 10.8
1,3-dichloropropene 18.5 to 25 0.275 17.7 to 24.6
methyl isothiocyanate 21 0.76 92

a measured in mm Hg at 200 C
bratio of weights of chemical in equilibrium, in equal volumes of water and air at approximately the
same temperature.







150 +


1 Tilled surface
r Sealed surface




Days after application

Figure 1. Concentration of 1,3-dichloropropene (Telone) in the upper 5 inches of soil
following broadcast application using the Yetter 30" Avenger.

...... i mI







2 4 6 8 10 12 14 16 18 20 22

Days after application

Figure 2. Concentration of 1L3-dichloropropenc in the upper 5 inches of soil. Saunples
cntlrl~~Vl (rom Ihe cCnte t Ot inch wide by 1 Inch tall beds.








Figure 3. The number ofnutsedge emerging through the plastic 37 days after application
of 1,3-dichloropropene at 35 gal per acre. All plastic was low density polyethylene
except for the VIF treatment.

VIF Research and Its Role in Methyl

Bromide Phaseout and Update on Long

Term Methyl Bromide Alternatives Study

James P. Gilreathl, Joseph W. Noling2, John P. Jones1,
Phyllis R. Gilreath3, Timothy N. Motis1, and Bielinski
M. Santos'
1UF/IFAS, GCREC, Bradenton, 2UF/IFAS, CREC, Lake Alfred,
3UF/IFAS, Manatee County Extension Service, Palmetto

The impending loss of methyl bromide as a soil fumigant will
impact the Florida tomato industry .i.,ifKt ,ri:. because it will mean a
change in the way we do things and the results we can expect. For the past
11 years we have researched chemical and nonchemical alternatives and
we have studied various ways to improve the results we get with some of
the more promising ones. We also have continued to evaluate new fumi-
gants as they come along and have investigated the integration of herbi-
cides with fumigants in an effort to provide the broadspectrum pest con-
trol required by the tomato industry. As a result, we know a lot more than
we used to about many products, but we still have not found the "silver
bullet" nor are we likely to.
We have worked in cooperation with the Florida Fruit and Vegetable
Association and the Florida Tomato Committee to prepare and submit
Critical Use Exemption (CUE) petitions in an attempt to buy the industry
some more time so we can provide the grower industry with the very best
information about what is available and how to use it. Two criteria criti-
cal to any CUE petition are demonstration of existence of an active, sci-
entifically valid research program to continue investigation of possible
alternatives and serious attempts at emission reduction. Our research and
extension programs are designed to do just that. This paper will provide
you with an overview of what has been done as well as what is being
done currently. It is our attempt to provide you with a report of "what we
did with your in..,,,:. since the Florida Tomato Committee has funded
much of our research. While this may seem like a frivolous sub-title for
a paper, it is one we take seriously as money is important to both the giver
and the receiver. Furthermore, we would like to encourage you to attend
field days and other activities where you can see what is being done with
your money. We especially would like to see more direct participation by
the members of the Florida Tomato Committee Research Committee
since they are the ones making the funding decisions for the Committee.
If field days are not convenient for research committee members, please
contact us directly to select a time for a site visit so you can see the results
of your investment in research designed to address your needs.
We completed the five year methyl bromide alternative study this
spring (2003) at the Gulf Coast Research and Education Center in
Bradenton and results have been very interesting. This study looked at 1)
the impact of fall applications of methyl bromide (67/33), Telone C-17 +
Tillam, and soil solarization on soilbome pests and fall tomato produc-
tion, 2) residual pest control in spring cropping practices (double cropped
cucumber, millet cover crop, and weed fallow), and 3) the effect of these
spring cropping practices on the subsequent fall tomato crop. The popu-
lation of all soilborne pests went up after the first year, then declined to
varying degrees. For example, the number of nutsedge plants per square
meter increased from 19 in the first year to 103 in the second year of
tomato with no fumigant, then the number declined and leveled off at
about 35 plants per square meter. Without fumigant, the amount of
Fusarium wilt infested tomato plants jumped from 32% to 89% then
declined slightly with a varying incidence level from one year to the next
for the remaining three years of the study. We also observed large fluctu-
ations in the population of rootknot and other nematodes from year to
year. Tomato marketable fruit production also varied from year to year in
the non-fumigated areas, but the general trend was that it declined each

year. In the first year, marketable fruit production was only 32% of what
was produced with methyl bromide, then it declined even further and was
only about 10% by the fifth year. Fruit production declined with all treat-
ments, including methyl bromide, which should be no surprise to a grow-
er. You can not continue to grow tomatoes on the same ground year after
year without expecting a yield decrease. Tomato production decreased
after the first year, but became fairly stable after that time; however, the
level at which it stabilized was only about 55% of what it was the first
year with methyl bromide. Results with Telone C-17 + Tillam were very
similar to what we obtained with methyl bromide and there were no sig-
nificant J.th i-n between the two fumigants for soilborne pest control,
with the exception of rootknot nematode control in the last year of the
study when there were fewer rootknot nematodes where we used Telone
C-17 than where we applied methyl bromide. Fruit yields were not dif-
ferent in any year with these two fumigants.
Soil solarization did not perform at all well. In some years we actu-
ally had more rootknot nematodes with solarization than where we used
no fumigant. Nutsedge control was not that J.ttc!!- ir from the fumigants
because we sprayed the emerged nutsedge with paraquat a week before
planting, effectively "burning off' a lot of the resident population. Four
out of five years, tomato fruit production with solarization was only about
one-half of what it was with methyl bromide and Telone C-17. As a
result, soil solarization is not considered a viable option for mainstream
agriculture. It might have a fit for an organic producer or a small grower
who can not obtain or afford soil fumigants.
The effect of the spring cropping practices on fall pest populations
and tomato production was a bit less complicated. Spring cropping prac-
tice had no effect on the amount of Fusarium wilt or rootknot nematode
galling of tomato roots. There were fewer nutsedge plants following dou-
ble -cropped cucumber the first year, but more the last year. Spring mil-
let increased fall tomato production one year, but that was the only time
that spring cropping practice had an influence on fall tomato yield.
As mentioned, we also looked at the effect of the fall alternative
treatments on spring production of double cropped cucumbers and millet
as a cover crop. Soil solarization reduced the number of nutsedge plants
as well as methyl bromide each year. This probably was the result of
allowing nutsedge to emerge and grow over the 8 week solarization peri-
od, then spraying it with paraquat to "bum it down" prior to transplanti-
ng in the fall. As a result, a lot of the nutsedge tubers sprouted in the fall
and were damaged by that paraquat application and the additional two
applications made at the end of the tomato crop and just prior to planting
cucumber in the spring. Telone C-17 + Tillam provided residual nutsedge
control equal to methyl bromide in 3 of the 4 spring cucumber crops. The
number of rootknot nematodes in the soil around cucumber roots was
only affected by fall treatment in the first spring of the study. At that time,
the most rootknot nematodes were found in the nontreated control plots
and where solarization was practiced. The fewest rootknot nematodes
were recovered in soil previously fumigated with Telone C-17.
Cucumber production was equal with methyl bromide and Telone C-17 +
Tillam in each year of this study while production with solarization was
as good as with methyl bromide during two years and worse during the
other two years. Growth (plant height and fresh weight) of millet was not
affected by Telone C-17 + Tillam, but solarization reduced millet plant
height and weight some years. The occurrence of nutsedge, crabgrass and
pigweed in millet was greater during the last year of the study with soil
Based on results of this study, we appear to have an option to methyl
bromide. That was the good news. The bad news is that the herbicide
component (Tillam) which provided nutsedge control is no longer regis-
tered for use in the U.S.A. It was the victim of the bankruptcy of its mar-
keting agent, Cedar Chemical Co. When Cedar Chemical went bankrupt,
no other company stepped forward to pay the registration fees which
were due in December 2002. As a result, Tillam is gone, probably forev-
er. Admittedly, Tillam had some short comings. Although it performed
well in this and many other studies we have conducted, there have been

a few where it caused injury or performed poorly. Cases of injury could
almost always be explained based on operator error, but some of the
instances of poor weed control could not. In order to be a replacement for
methyl bromide, an alternative must be effective and it must provide con-
sistent results. While there are other herbicides being investigated for use
in combination with some of the alternative fumigants, we do not have
the extensive experience with them that we have with Tillam; therefore,
it will take time to identify the strengths and weaknesses of each and
determine exactly how they fit with the more promising alternatives to
achieve the ultimate goal of providing a replacement package which will
allow a grower to continue producing tomatoes with minimal additional
risk or costs.
As mentioned, additional research has been conducted on soil fumi-
gants for tomato. This has ranged from fine tuning Telone products to
exploration of new compounds. Since Telone has proven to be the most
likely replacement for methyl bromide in the near future, we have inves-
tigated means of improving efficacy and consistency of performance.
There has been a great deal of emphasis on broadcast applications of
Telone C-35 as a means of reducing worker exposure and the impact of
personal protective equipment (PPE) requirements and broadcast has
appeared to work well in most situations in commercial scale trials; how-
ever, experiments on commercial farms seldom provide the high level of
pest pressure one can attain in small plot research on an experiment sta-
tion where pest levels have been developed for just such purposes.
Over the past 3 years we have conducted a study investigating the rela-
tive efficacy of Telone C-35 when applied broadcast versus in the bed and
the impact of additional chloropicrin applied at the time of bed formation.
We have determined that under conditions of moderate disease pressure
Telone C-35 applied in the bed is more efficacious than broadcast Telone
C-35. Application of additional chloropicrin in the bed following broad-
cast Telone C-35 improves soilbome disease control and nematode con-
trol. We included Tillam + Devrinol for weed control with all applica-
tions of Telone II and Telone C-35 in this study and determined that even
with herbicide the same across treatments, in bed Telone C-35 provided
better nutsedge control than any broadcast Telone treatment. We also
found that adding chloropicrin back into the bed following broadcast
Telone II or Telone C-35 improved nutsedge control. Tomato marketable
fruit production followed the same trend. Methyl bromide was included
as a grower standard and Telone C-35 in bed with Tillam + Devrinol
applied broadcast provided soilbome pest control and tomato yield equal
to methyl bromide. Recent changes in the PPE requirements and setbacks
for Telone products have eased the impacts of those issues for growers
wishing to make in bed applications, so it is felt that there will be less
interest in broadcast application, although there are some very real bene-
fits to broadcast that should be considered. The take home message for a
grower is if you are going to apply Telone C-35 broadcast, you should
apply another 125 to 150 pounds of chloropicrin per treated acre in the
While we have spent time fine tuning Telone C-35 we also have con-
tinued to search for new compounds as well as older products which may
have value for soil fumigation in tomato. By leveraging Florida Tomato
Committee funds with funds obtained from the USDA /IR-4 Methyl
Bromide Alternatives Program we have been able to conduct 4 large
experiments over the past 2 years. Twenty-four treatments were evaluat-
ed in 2001 and 18 were investigated in 2002. One trial is being repeated
this fall as a result of loss of the experiment due to pinworms. (Yes, even
scientists have pest control problems that get out of hand.) As a result of
these experiments, about 4 products have been dropped from further test-
ing, 1 is awaiting labeling, and 3 are continuing to be evaluated. One of
the success stories is fosthiazate. Registration of fosthiazate is being pur-
sued by Syngenta and the combination of chloropicrin chiseled into the
bed and fosthiazate applied through the drip irrigation system has been
one of the best treatments for soilbome diseases and nematodes in these
A promising new product is sodium azide. Sodium azide has been

around for over 30 years and was first investigated as a soil fumigant by
PPG Industries in the early to mid 1970's. At that time it was formulated
as a granular product and showed great promise. Unfortunately, PPG
chose to shelve it because methyl bromide was firmly entrenched in the
market place and azide is not without some risks. Today it is available for
research purposes formulated as a liquid preparation. We have investi-
gated 2 application procedures: spray on the soil surface and incorporate
it with a rototill and apply it through the drip irrigation system. Drip
application is preferable because it reduces potential worker exposure,
but drip brings with it problems we have discussed before about the
uneven distribution of water soluble products in sandy soils. In a trial on
a commercial farm near Immokalee, sodium azide provided better control
of Fusarium crown rot than methyl bromide, and it has performed well
for control of Fusarium wilt race 3 in trials in Manatee county; however,
results have not always been consistent. Nutsedge control has been good
in some trials and poor in others, including trials with crops other than
tomatoes. Some formulation changes have occurred which seem to have
improved performance. Spray rototill application has not been as effec-
tive as drip application. Work continues with sodium azide in collabora-
tion with a scientist from Auburn and we hope to have more definitive
results to present next year.
We also have investigated a new product from South Africa which is
being developed under the trade name Multiguard Protect. This product
is a contact nematicide and is being marketed in South Africa for toma-
toes. Results in our trials have been mixed and we believe some of this is
due to difficulty distributing it uniformly across the bed. One interesting
aspect of this product is the crop safety which allows applications during
the season. This would allow it to fit in both a first crop as well as a dou-
ble crop or be used as a rescue treatment, if we can improve the efficacy
and consistency in our sandy soils.
Vapam and K-Pam continue to be included in research because they
can provide nutsedge control which is not possible with most other alter-
native fumigants and because we have seen improvement in efficacy and
consistency as a result of research we conducted in the past 3 years to
determine the movement of water soluble pesticides in soil water as a
result of drip irrigation application. One promising treatment is the com-
bination of Vapam or K-Pam with either chloropicrin or Telone C-35.
Vapam / K-Pam would be delivered through the drip tubing in this com-
Inline, an emulsifiable concentrate form of Telone C-35, has been
included in some research and results have been mixed; again as the
result of drip delivery problems. We have managed to make improve-
ments and work continues. Probably the real place for Inline is in double
cropping as a supplemental treatment just prior to planting the double
One of the big concerns with alternatives to methyl bromide is the
potential impact of the alternative on residual soilborne pest levels. This
is particularly important for double cropping. The 5 year study we just
completed did a lot to address growers' concerns about the potential for
buildup following Telone C-17, methyl bromide and soil solarization. We
determined that there was some increase in pest levels with all treatments,
including methyl bromide, but solarization was far worse. Upon termina-
tion of that study we began a new study to measure the potential buildup
of nutsedge, Fusarium wilt race 3, and nematodes following cessation of
fumigation when the double crop was tomato. Tomato behind tomato is a
recipe for disaster, but it allows you to better determine the impacts than
double crop cucurbits because it allows a measure of Fusarium wilt in
addition to nutsedge and nematodes. We found that there was tremendous
resurgence with methyl bromide as well as Telone C-17 and that there
was no .i"tc!c-L.i, in the extent of resurgence. We hope to expand this
project to include additional alternatives this fall and spring.
Lastly we come to what was supposed to be the focus of this paper:
VIF or virtually impermeable film. We have been working with VIF
products for about 5 years now. Some are good and some are not. None
are embossed, at this time. As a result, they do not stretch or have any

"memory" which allows them to shrink and swell with temperature
changes. Some are prone to linear shear. Before we say ,ii.hri.;i else, we
need to define what VIF is. Virtually impermeable film is not imperme-
able to methyl bromide, but it is much less permeable than low density
polyethylene (ldpe) film which is the standard mulch you use.
Permeability can be on the order of more than 10 times less permeable.
Today you may see "High Barrier" film on the market. This is not VIF. It
is less permeable than standard Idpe but still much more permeable than
VIF. How much more permeable? The published standard for High
Barrier comes from the California Dept. of Agriculture and specifies a
film which can be as much as 25 times more permeable than VIF. One of
the problems with VIF is the lack of a international standard for this
film's permeability. The only known published standard for VIF is pro-
vided by the French who state that to be classified as a VIF, a film must
have a transmission rate of no more than 0.2 grams (or milliliters) per
square meter of film per hour.
VIF can play an important role in rate and emissions reduction with
methyl bromide. Recently completed research with pepper demonstrated
just how effective VIF could be at improving efficacy of reduced rates of
methyl bromide. This study was repeated over several years and clearly
demonstrated that rates as low as 88 lbs of 67/33 per treated acre could
provide nutsedge control equal to that obtained with 350 lbs of 676/33
when VIF was substituted for standard Idpe or High Barrier polyethylene
film. We do not encourage growers to try such low rates, but we do feel
that with a good VIF rates can be cut in half without suffering loss of effi-
Not all fumigants benefit from VIF. Telone C-35 does, but many oth-
ers do not. It is difficult to comprehend the gas retention capacity of VIF
relative to Idpe, but the following may help put it into perspective. In a
study of Telone C-35 retention rates of various films, the transmission
rate for standard Idpe black film was measured as 45% in 81 hours, while
one of the more successful VIF products had a transmission rate of 4% in
81 hours in one study (data courtesy of Joseph E. Eger, Dow
AgroSciences). Results of field experiments with Inline and Telone C-35
have demonstrated improved retention with VIF. Thus, one can see clear-
ly that VIF can play an important role with Telone C-35 as well as methyl
bromide. The longer retention time means more effective control of sus-
ceptible soilborne pests. It can also mean improvements in control of
more difficult to control pests, like nutsedge. Results of research con-
ducted over the past 2 years have illustrated this concept. By combining
Telone C-35 or Inline with VIF we have greatly improved nutsedge con-
trol. Furthermore, drip application of Inline with ldpe has always suffered
from poor control of nutsedge along the bed shoulder and control was
restricted to an area about 6 inches on either side of the drip tubing. With
VIF we have been able to achieve a much wider band of control and
much better control within the impacted zone when we have applied
Inline through the drip tubing. While VIF retains methyl bromide and
Telone longer than standard Idpe or "High Barrier" films and results in
greatly improved soilbore pest control, there is a down side. Most VIF
does not lay that well. Laying speeds of 2 to 3 mph are common as faster
speeds increase the risk of linear shear. This is too slow for most grow-
ers. Another problem observed has been loosening of the film as it heats
up J1,,1!;,. ri ,- J d:. The inability to lay some VIF's tightly and the need for
reduced laying speed make many of these films unacceptable to growers.
Not all VIFs are the same. Just as there are %.ittci -, c- in retention char-
acteristics, there also can be d.ittic-L .c, in handling properties and we
continue to trial new films as they are made available. Cin iri:. we favor
VIF manufactured by IPM of Italy. Their film is not quite as retentive as
some, but it handles better than any of the other films we have laid. We
have laid this film at 4 to 4.5 mph without mishap and have experienced
no problem with linear shear or any other type of tearing action. We have
noted that their white on black is not as white as we would like it to be,
but they are working on improving the brightness of the product and we
do not expect that to impact handling characteristics.
The ini c ,r mniri, i bromide alternatives research program is a large

one. We have worked to deliver what the industry needs effective alter-
natives, data to support a CUE, and information on fumigant and mulch
options so growers can make intelligent, informed decisions. We feel you
have invested your money wisely and we hope you feel that you have
received good value for that investment. Lastly, we would like to once
again encourage tomato growers and their representatives to visit and
view the research being conducted on your behalf. Direct involvement by
the industry is important for all of us.


Tomato Varieties for Florida Stephen M. Olson, UF, NFREC, Quincy; and Donald N. Maynard, UF, GCREC,
Bradenton, pg. 42

Water Management for Tomato Eric H. Simonne, Horticultural Sciences Department, UF, Gainesville, pg. 45

Fertilizer and Nutrient Management for Tomato Eric H. Simonne, Horticultural Sciences Department, UF,
Gainesville, pg. 49

Weed Control in Tomato William H. Stall, Horticultural Sciences Department, UF, Gainesville;
James P.Gilreath, UF, GCREC, Bradenton, pg. 56

Chemical Disease Management for Tomato Tom Kucharek, Plant Pathology Department,
UF, Gainesville, pg. 59

Selected Insecticides Approved for Use on Insects Attacking Tomatoes S. E. Webb, Entomology &
Nematology Department, UF, Gainesville, pg. 62

Nematicides Registered for Use in Florida Tomatoes J. W. Noling, UF, CREC, Lake Alfred, pg. 68

Tomato Varieties for Florida

Stephen M. Olsoni and Donald N. Maynard2
1North Florida Research & Education Center, Quincy, 2Gulf
Coast Research & Education Center, Bradenton

Variety selections, often made several months before planting,
are one of the most important management decisions made by the
grower. Failure to select the most suitable variety or varieties may
lead to loss of yield or market acceptability.
The following characteristics should be considered in selection
of tomato varieties for use in Florida.
* Yield The variety selected should have the potential to produce
crops at least equivalent to varieties already grown. The average
yield in Florida is n, ii-Lri'. about 1400 25-pound cartons per acre.
The potential yield of varieties in use should be much higher than
* Disease Resistance Varieties selected for use in Florida must
have resistance to Fusarium wilt, race 1, race 2 and in some areas
race 3; Verticillium wilt (race 1); gray leaf spot; and some tolerance
to bacterial soft rot. Available resistance to other diseases may be
important in certain situations, such as Tomato Spotted Wilt resist-
ance in northwest Florida.
* Horticultural Quality Plant habit, stem type and fruit size,
shape, color, smoothness and resistance to defects should all be con-
sidered in variety selection.
* Adaptability Successful tomato varieties must perform well
under the range of environmental conditions usually encountered in
the district or on the individual farm.
* Market Acceptability The tomato produced must have charac-
teristics acceptable to the packer, shipper, wholesaler, retailer and
consumer. Included among these qualities are pack out, fruit shape,
ripening ability, firmness, and flavor.

Current Variety Situation
Many tomato varieties are grown commercially in Florida, but
only a few represent most of the acreage. In years past we have been
able to give a breakdown of which varieties are used and predomi-
,11'. 1 1., iL they were being used but this information is no longer
available through the USDA Crop Reporting Service.

Tomato Variety Trial Results
Summary results listing the five highest yielding and the five
largest fruited varieties from trials conducted at the University of
Florida's Gulf Coast Research and Education Center, Bradenton;
Indian River Research and Education Center, Ft. Pierce and North
Florida Research and Education Center, Quincy for the Spring 2002
season are shown in Table 1. High total yields and large fruit size
were produced by Fla. 7926 at Bradenton; Florida 47, Fla. 7810,
Agriset 761 and Sanibel at Fort Pierce; and SVR 1432427 and BHN
444 at Quincy. There was very little overlap between locations. The
same entries were not included at all locations.
Table 2 shows a summary of results listing the five highest
yielding and five largest fruited entries from trials at the University
of Florida's Gulf Coast Research and Education Center, Bradenton;
Indian River Research and Education Center, Ft. Pierce and the
North Florida Research and Education Center, Quincy for the Fall
2002 season. High total yields and large fruit size were produced by
Fla. 7810, Fla. 7885 B, Florida 47 and Florida 91 at Fort Pierce and
by Solar Fire and Fla. 7885 B at Quincy. Solar Fire and Fla. 7885 B
produced high yields at all three locations and Fla. 7885 B, Fla. 7810

and Florida 91 produced large fruit at two of three locations. Not all
entries were included at all locations.

Tomato Varieties for Commercial Production
The varieties listed below have performed well in University of
Florida trials conducted in various locations in recent years.

Large Fruited Varieties
Agriset 761. Midseason, determinate, jointed hybrid. Fruit are deep
globe and green shouldered. Resistant: Verticillium wilt (race 1),
Fusarium wilt (race 1 and 2), Altemaria stem canker, gray leaf spot.

BHN 640. Early-midseason maturity. Fruit are globe shape but tend
to slightly elongate, and green shouldered. Not for fall planting.
Resistant: Verticillium wilt (race 1), Fusarium wilt (race 1, 2 and 3),
gray leaf spot, and Tomato Spotted Wilt. For Trial. (BHN).

Florida 47. A late midseason, determinate, jointed hybrid. Uniform
green, globe-shaped fruit. Resistant: Fusarium wilt (race 1 and 2),
Verticillium wilt (race 1), Altemaria stem canker, and gray leaf spot.

Florida 91. Uniform green fruit borne on jointed pedicels.
Determinate plant. Good fruit setting ability under high tempera-
tures. Resistant: Verticillium wilt (race 1), Fusarium wilt (race 1 and
2), Alternaria stem canker, and gray leaf spot. (Seminis).

Floralina. A midseason, determinate, jointed hybrid. Uniform,
green shoulder, flattened, globe-shaped fruit. Recommended for
production on land infested with Fusarium wilt, Race 3. Resistant:
Fusarium wilt (race 1, 2, and 3), Verticillium wilt (race 1), gray leaf
spot. (Seminis).

Sebring. A late midseason determinate, jointed hybrid with a
smooth, deep oblate, firm, thick walled fruit. Resistant: Verticillium
wilt (race 1), Fusarium wilt (racel,2 and 3), Fusarium crown rot and
gray leaf spot. For Trial. (Syngenta)

Solar Fire. An early, determinate, jointed hybrid. Has good fruit set-
ting ability under high temperatures. Fruit are large, flat-round,
smooth, firm, light green shoulder and blossom scars are smooth.
Resistant: Verticillium wilt (race 1), Fusarium wilt (race 1,2 and 3)
and gray leaf spot. For Trial. (University of Florida)
Solar Set. An early, green-shouldered, jointed hybrid. Determinate.
Fruit set under high temperatures (92oF day/72o night) is superior to
most other commercial varieties. Resistant: Fusarium wilt (race 1
and 2), Verticillium wilt (race 1), Alternaria stem canker, and gray
leaf spot. (Seminis).

Sanibel. A late-midseason, jointless, determinate hybrid. Deep
oblate shape fruit with a green shoulder. Tolerant/resistant:
Verticillium wilt (race 1), Fusarium wilt (race 1 and 2), Altemaria
stem canker, root-knot nematode, and gray leaf spot. (Seminis).

Solimar. A midseason hybrid producing globe-shaped, green shoul-
dered fruit. Resistant: Verticillium wilt (race 1), Fusarium wilt (race
1 and 2), Altemaria stem canker, gray leaf spot. (Seminis).

Sunbeam. Early midseason, deep-globe shaped uniform green fruit
are produced on determinate vines. Resistant: Verticillium wilt (race
1), Fusarium wilt (race 1 and race 2), gray leaf spot, Alternaria stem
canker. (Seminis).

Plum Type Varieties
Marina. Medium to large vined determinate hybrid. Rectangular,
blocky, fruit may be harvested mature green or red. Resistant:
Verticillium wilt (race 1), Fusarium wilt (race 1 and 2), Altemaria
stem canker, root-knot nematodes, gray leaf spot, and bacterial
speck. (Sakata).

Plum Dandy. Medium to large determinate plants. Rectangular,
blocky, defect-free fruit for fresh-market production. When grown in
hot, wet conditions, it does not set fruit well and is susceptible to
bacterial spot. For winter and spring production in Florida.
Resistant: Verticillium wilt, Fusarium wilt (race 1), early blight, and
rain checking. (Harris Moran).

Spectrum 882. Blocky, uniform-green shoulder fruit are produced
on medium-large determinate plants. Resistant: Verticillium wilt
(race 1), Fusarium wilt (race 1 and 2), root-knot nematode, bacteri-
al speck (race 0), Altemaria stem canker, and gray leaf spot.

Supra. Determinate hybrid rectangular, blocky, shaped fruit with
uniform green shoulder. Resistant: Verticillium wilt (race 1),
Fusarium wilt (race 1 and 2), root-knot nematodes, and bacterial
speck. (Syngenta).

Veronica. Tall determinate hybrid. Smooth plum type fruit are uni-
form ripening. Good performance in all production seasons.
Resistant: Verticillium wilt (race 1), Fusarium wilt (race 1 and 2),
Altemaria stem canker, nematodes, gray leaf spot and bacterial
speck. (Sakata).

Cherry Type Varieties
Mountain Belle. Vigorous, determinate type plants. Fruit are round
to slightly ovate with uniform green shoulders borne on jointless
pedicels. Resistant: Fusarium wilt (race 2), Verticillium wilt (race 1).
For trial. (Syngenta).

Cherry Grande. Large, globe-shaped, cherry-type fruit are pro-
duced on medium-size determinate plants. Resistant: Verticillium
wilt (race 1), Fusarium wilt (race 1), Alternaria stem blight, and gray
leaf spot. (Seminis).

This information was gathered from results of tomato variety trials
conducted during 2002 at locations specified in each table. Tomato
variety evaluations were conducted in 2002 by the following
University of Florida faculty:

D. N. Maynard. Gulf Coast Research & Education Center -
S. M. Olson. North Florida Research & Education Center -
P. J. Stoffella. Indian River Research & Education Center Fort

Table 1. Summary of University of Florida tomato variety trial results. Spring 2002.
Location Variety Total yield (ctn/acre) Variety Average fruit wt. (oz)
Bradenton Fla. 7973 2967 RFT 0417 7.6
Fla. 7926 2799 PX 150535 7.4
HMX 1803 2787 XTM 0227 7.3
BHN 591 2749 EX1405037 7.3
BHN 586 27171 Fla. 7926 7.22

Fort Pierce Florida 47 3528 Sanibel 6.4
Fla. 7810 3286 Florida 47 6.4
Agriset 761 3189 Fla. 7810 6.3
Sanibel 3108 Florida 91 6.3
Fla. 7973 30843 Agriset 761 6.04

Quincy RFT 0849 2771 BHN 543 8.2
BHN 640 2695 SVR 1432427 7.9
SVR 1432427 2641 Sunpac 7.6
BHN 444 2633 BHN 444 7.5
BHN 577 24965 Fla. 7973 7.56

119 other entries had yields similar to BHN 586.
218 other entries had fruit weight similar to PX 150535.
32 other entries had yields similar to Fla. 7973.
42 other entries had fruit weight similar to Agriset 761.
513 other entries had yields similar to BHN 577.
614 other entries had fruit weight similar to Fla. 7973.

Seed Sources:
Agrisales: Agriset 761.
BHN: BHN 444, BHN 543, BHN 577, BHN 586, BHN 591, BHN 640.
Harris Moran: HMX 1803.
Seminis: Florida 47, Florida 91, Sanibel, Sunpac, PX 150535,
EX 1405037, SVR 1432427.
Sakata: XTM 0227
Syngenta: RFT 0417, RFT 0849
University of Florida: Fla. 7810, Fla. 7926, Fla. 7973.

Table 2. Summary of University of Florida tomato variety trial results. Fall 2002.
Location Variety Total yield (ctn/acre) Variety Average fruit wt. (oz)
Bradenton Solar Fire 1480 XTM 0231 6.9
Solar Set 1461 Florida 91 6.9
XTM 0231 1389 HMX 1803 6.8
Lucky 13 1387 BHN 650 6.8
Fla. 7885 B 13571 XTM 0227 6.72

Fort Pierce Fla. 7810 1697 Florida 47 5.1
Fla. 7885 B 827 Solar Set 5.0
Florida 47 781 Florida 91 4.9
Florida 91 630 Fla. 7810 4.9
Solar Fire 5653 Fla. 7885 B 4.84

Quincy Solar Fire 1641 Solar Fire 6.4

Fla. 7885 B
Solar Set
XTM 0230
SVR 145037


Fla. 7885 B
XTM 0227
BHN 640
Fla. 7810

114 other entries had yields similar to Fla. 7885 B.
2 11 other entries had fruit weight similar to XTM 0227.
3 2 other entries had yields similar to Solar Fire.
4 2 other entries had fruit weight similar to Fla. 7885 B.
5 17 other entries had yields similar to SVR 145037.
6 11 other entries had fruit weight similar to Fla. 7810.

Seed Sources:
Agrisales: Lucky 13
BHN: BHN 640, BHN 650.
Harris Moran: HMX 1803.
Sakata: XTM 0227, XTM 0230, XTM 0231.
Seminis: Florida 47, Florida 91, Sanibel, Solar Set, SVR 1405037.
University of Florida: Solar Fire, Fla.7810, Fla. 7885 B.

Water Management For Tomato

Eric Simonne, Horticultural Sciences Department, UF,

Approximately 45,000 acres of tomatoes were harvested in
Florida during the 2002-2003 growing season. The value of the
fresh-market tomato crop that year was estimated at slightly above
$508 million (USDA, National Agricultural Statistics Service,
Vegetable Summary; lirTp j II II .Iilii L.-I ,cll ct.J !cp.'!T, Ii I,,!/
fruit/pvg-bban/vgan0103.txt). The main areas of production are
Gadsden county (Quincy), Manatee county (Palmetto-Ruskin),
Hendry and Collier counties (southwest), Palm Beach county
(southeast coast), and Dade county (Homestead). Production started
in Suwannee county (Live Oak) in 2001 and has increased since
then. Most of the tomato acreage today uses plasticulture (raised
beds, polyethylene mulch and drip irrigation) Some tomatoes are
still grown with polyethylene mulch and seepage irrigation.
Water and nutrient management are two important aspects of
tomato production in all these production systems. Water is used for
wetting the fields before land preparation, transplant establishment,
and irrigation. The objective of this article is to provide an overview
of recommendations for tomato irrigation in Florida.
Recommendations in this article should be considered together with
those presented in the 'Fertilizer and nutrient management for toma-
to' section, also included in this publication.
Irrigation is used to replace the amount of water lost by tran-
spiration and evaporation. This amount is also called crop evapo-
transpiration (ETc). Irrigation scheduling is used to apply the proper
amount of water to a tomato crop at the proper time. The character-
istics of the irrigation system, tomato crop needs, soil properties, and
atmospheric conditions must all be considered to properly schedule
irrigations. Poor timing or insufficient water application can result in
crop stress and reduced yields from inappropriate amounts of avail-
able water and/or nutrients. Excessive water applications may
reduce yield and quality, are a waste of water, and increase the risk
of nutrient leaching
A wide range of irrigation scheduling methods is used in
Florida, with corresponding levels of water managements (Table 1).
The recommend method to schedule irrigation for tomato is to use
together an estimate of the tomato crop water requirement that is
based on plant growth, a measurement of soil water status and a
guideline for splitting irrigation (water management level 5 in Table
1). The estimated water use is a guideline for irrigating tomatoes.
The measurement of soil water tension is useful for fine tuning irri-
gation. Splitting irrigation events is necessary when the amount of
water to be applied is larger than the water holding capacity of the
root zone

Tomato water requirement. Tomato water requirement (ETc)
depends on stage of growth, and evaporative demand. ETc can be
estimated by adjusting reference evapotranspiration (ETo) with a
correction factor call crop factor (Kc; equation [1]). Because differ-
ent methods exist for estimating ETo, it is very important to use Kc
coefficients which were derived using the same ETo estimation
method as will be used to determine ETc. Also, Kc values for the
appropriate stage of growth and production system (Table 2) must be
By definition, ETo represents the water use from a uniform
green cover surface, actively growing, and well watered (such as a
turf or grass covered area). ETo can be measured on-farm using a
small weather station. When daily ETo data are not available, his-
torical daily averages of Penman-method ETo can be used (Table 3).
However, these long-term averages are provided as guidelines since

actual values may fluctuate by as much as 25%, either above the
average on hotter and drier than normal days, or below the average
on cooler or more overcast days than normal. As a result, SWT or
soil moisture should be monitored in the field.

Eq. [1]
Crop water requirement = Crop coefficient x Reference evapotranspiration
ETc = Kc x ETo

Tomato irrigation requirement (IR). Irrigation systems are
generally rated with respect to application efficiency ( F iI which is
the fraction of the water that has been applied by the irrigation sys-
tem and that is available to the plant for use. In general, Ea is 60-
80% for overhead irrigation, 20-70% for seepage irrigation, and 90-
95% for drip irrigation. Applied water that is not available to the
plant may have been lost from the crop root zone through evapora-
tion or wind drifts of spray droplets, leaks in the pipe system, sur-
face runoff, subsurface runoff, or deep percolation within the irri-
gated area. Tomato IR are determined by dividing the desired
amount of water to provide to the plant (ETc), by Ea as a decimal
fraction (Eq. [2]).

Eq. [2]
Irrigation requirement = Crop water requirement / Application efficiency

In areas where real-time weather information is not available,
growers use the '1,000 gal/acre/day/string' rule for drip-irrigated,
winter production. As the tomato plants grow from 1 to 4 strings, the
daily irrigation volumes increase from 1,000 gal/acre/day to 4,000
gal/acre/day. On 6-ft centers, this corresponds to 15 gal/1001bf/ day
and 60 gal/1001bf/day for 1 and 4 strings, respectively.

Soil water status and soil water tension measurement. Soil
water tension (SWT) represents the magnitude of the suction (nega-
tive pressure) the plant roots have to create to free soil water from
the attraction of the soil particles, and move it into its root cells. The
dryer the soil, the higher the suction needed, hence, the higher SWT.
SWT is commonly expressed in centibars (cb) or kiloPascals (kPa;
Icb = IkPa). For tomatoes grown on the sandy soils of Florida, SWT
in the rooting zone should be maintained between 6 (field capacity)
and 15 cb.
The two most common tools available to measure SWT in the
field are tensiometers, and time domain reflectometry (TDR).
Tensiometers have been used for several years in tomato production.
A porous cup is saturated with water, and placed under vacuum. As
the soil water content changes, water comes in or out of the porous
cup, and affects the amount of vacuum inside the tensiometer.
Tensiometer readings have been successfully used to monitor SWT
and schedule irrigation for tomatoes. However, because they are
fragile and easily broken by field equipment, many growers have
renounced to use them. In addition, readings are not reliable when
the tensiometer dries, or when the contact between the cup and the
soil is lost. Depending on the length of the access tube, tensiometers
cost between $40 and $80 each. Tensiometers can be reused as long
as they are maintained properly and remain undamaged.
It is necessary to monitor SWT at two soil depths when ten-
siometers are used. A shallow 6-in depth is useful at the beginning
of the season when tomato roots are near that depth. A deeper 12-in
depth is used to monitor SWT during the rest of the season.
Comparing SWT at both depths is useful to understand the dynam-
ics of soil moisture. When both SWT are within the 4-8 cb range
(close to field capacity), this means that moisture is plentiful in the
rooting zone. This may happen after a large rain, or when tomato
water use is less than irrigation applied. When the 6-in SWT

increases (from 4-8 cb to 10-15cb) while SWT at 12-in remains
within 4-8, the upper part of the soil is drying, and it is time to irri-
gate. If the 6-in SWT continues to raise (above 25cb), a water stress
will result; plants will wilt, and yields will be reduced. This should
not happen under adequate water management.
A SWT at the 6-in depth remaining within the 4-8 cb range, but
the 12-in reading showing a SWT of 20-25 cb suggest that deficit
irrigation has been made: irrigation has been applied to re-wet the
upper part of the profile only. The amount of water applied was not
enough to wet the entire profile. If SWT at the 12-in depth contin-
ues to increase, then water stress will become more severe and it will
become increasingly difficult to re-wet the soil profile. The sandy
soils of Florida have a low water holding capacity. Therefore, SWT
should be monitored daily and irrigation applied at least once daily.
Scheduling irrigation with SWT only can be difficult at times.
Therefore, SWT data should be used together with an estimate of
tomato water requirement.
Times domain reflectometry (TDR) is not a new method for
measuring soil moisture but its use in vegetable production has been
limited in the past. The recent availability of inexpensive equipment
($500 to $700/unit) has increased the potential of this method to
become practical for tomato growers. A TDR unit is comprised of
three parts: a display unit, a sensor, and two rods. Rods may be 4
inches or 8 inches in length based on the depth of the soil. Long rods
may be used in all the sandy soils of Florida, while the short rods
may be used with the gravelly soils of Miami-Dade county.
The advantage of TDR is that probes need not be buried per-
n i,, llc ri and readings are available instantaneously. This means
that, unlike the tensiometer, TDR can be used as a hand-held,
portable tool. As the potential use of TDR as an on-farm tool for
scheduling irrigation for vegetables is still under evaluation, it
should be used cautiously.
TDR actually determines percent soil moisture (volume of
water : volume of soil). In theory, a soil water release curve has to
be used to convert soil moisture to SWT. However, because TDR
provides an average soil moisture reading over the entire length of
the rod (as opposed to the specific depth used for tensiometers), it is
not practical to simply convert SWT into soil moisture to compare
readings from both methods. Preliminary tests with TDR probes
have shown that best soil monitoring may be achieved by placing the
probe vertically, approximately 6 inches away from the drip tape on
the opposite side of the tomato plants. For fine sandy soils, 9% to
15% appears to be the adequate moisture range. Tomato plants are
exposed to water stress when soil moisture is below 8%. Excessive
irrigation may result in soil moisture above 16%.

Guidelines for splitting irrigation. For sandy soils, a one
square foot vertical section of a 100-ft long raised bed can hold
approximately 24 to 30 gallons of water (Table 4). When drip irri-
gation is used, lateral water movement seldom exceeds 6 to 8 inch-
es on each side of the drip tape (12 to 16 inches wetted width). When
the volume of an irrigation exceeds the values in table 4, then irriga-
tion should be split. Splitting will not only reduce nutrient leaching,
but will also increase tomato quality by ensuring a more continuous
water supply. Uneven water supply may result in fruit cracking.

Units for measuring irrigation water. When overhead and
seepage irrigation were the dominant methods of irrigation, acre-
inches or vertical amounts of water were used as units for irrigations
recommendations. There are 27,150 gallons in one acre-inch; thus,
total volume was calculated by multiplying the recommendation
expressed in acre-inch by 27,150. This unit reflected quite well the
fact that the entire field was wetted.
Acre-inches are still used for drip irrigation, although the entire
field is not wetted. This section is intended to J1 .i f-, rl conventions

used in measuring water amounts for drip irrigation. In short, water
amounts are handled similarly to fertilizer amounts, i.e., on an acre
basis. When an irrigation amount expressed in acre-inch is recom-
mended for plasticulture, it means that the recommended volume of
water needs to be delivered to the row length present in a one-acre
field planted at the standard bed spacing. So in this case, it is nec-
essary to know the bed spacing to determine the exact amount of
water to apply. In addition, drip tape flow rates are reported in gal-
lons/hour/emitter or in gallons/hour/100 ft of row. C....lcqcirii,
tomato growers tend to think in terms of multiples of 100 linear feet
of bed, and ultimately convert irrigation amounts into duration of
irrigation. It is important to correctly understand the units of the
irrigation recommendation in order to implement it correctly.

Example. How long does an irrigation event need to last if a
tomato grower needs to apply 0.20 acre-inch to a 2-acre tomato
field. Rows are on 6-ft centers and a 12-ft spray alley is left unplant-
ed every six rows? The drip tape flow rate is 0.30 gallons/hour/emit-
ter and emitters are spaced 1 foot apart.

1. In the 2-acre field, there are 14,520 feet of bed (2 x 45,560/6).
Because of the alleys, only 6/8 of the field is actually planted. So,
the field actually contains 10,890 feet of bed (14,520x 6/8).

2. A 0.20 acre-inch irrigation corresponds to 5,430 gallons applied to
7,260 feet of row, which is equivalent to 75 gallons/100 feet

3. The drip tape flow rate is 0.30 gallons/hr/emitter which is equiv-
alent to 30 gallons/hr/100feet. It will take 1 hour to apply 30 gal-
lons/100ft, 2 hours to apply 60 gallons/100ft, and 2 2 hours to
apply 75 gallons. The total volume applied will be 8,168 gal-
lons/2-acre (75 x 108.9).

Table 1. Levels of water management and corresponding irrigation scheduling method for tomato

Water Management
Level Rating

Irrigation scheduling method

0 None Guessing (irrigate whenever)
1 Very low Using the 'feel and see' method
2 Low Using systematic irrigation (example: 2 hrs every day)
3 Intermediate Using a soil moisture measuring tool to start irrigation
4 Advanced Using a soil moisture measuring tool to schedule irrigation
and apply amounts based on a budgeting procedures
5 Recommended Using together a water use estimate based on tomato plant
stage of growth, a measurement of soil water moisture, and
a guideline for splitting irrigation

Table 2. Crop coefficient estimates (Kc) for tomato.
Tomato Growth Stage Bare Ground, Overhead Irrigated Plasticulture

1 0.20 to 0.40 0.30

2 0.20 to 0.40 0.40

3 1.15 0.90

4 1.15 0.90

5 1.00 0.75
z Actual values will vary with time of planting, length of growing season and
other site-specific factors. Kc values should be used with ETo values in Table
2 to estimated crop evapotranspiration (ETc)

Table 3. Historical Penman-method reference ET (ETo) for four Florida locations (in gallons per
acre per day)
Month Tallahassee Tampa West Palm Beach Miami
January 1,630 2,440 2,720 2,720
February 2,440 3,260 3,530 3,530
March 3,260 3,800 4,340 4,340
April 4,340 5,160 5,160 5,160
May 4,890 5,430 5,160 5,160
June 4,890 5,430 4,890 4,890
July 4,620 4,890 4,890 4,890
August 4,340 4,620 4,890 4,620
September 3,800 4,340 4,340 4,070
October 2,990 3,800 3,800 3,800
November 2,170 2,990 3,260 2,990
December 1,630 2,170 2,720 2,720
z assuming water application over the entire area, i.e., sprinkler or seepage irrigation with 100%

Table 4. Estimated maximum water application (in gallons per acre and in gallons/1001fb) in one
irrigation event for tomato grown on 6-ft centers (7,260 linear bed feet per acre) on sandy soil
(available water holding capacity 0.75 in/ ft and 50% soil water depletion). Split irrigations may
be required during peak water requirement.
Wetting Gal/100ft Gal/100ft Gal/100ft Gal/acre Gal/acre Gal/acre
width to wet to wet to wet to wet to wet to wet
(ft) depth of depth of depth of depth of depth of depth of
1 ft 1.5 ft 2 ft 1 ft 1.5ft 2 ft
1.0 24 36 48 1,700 2,600 3,500

1.5 36 54 72 2,600 3,900 5,200

Fertilizer And Nutrient Management For


E.H. Simonne and G.J. Hochmuth
Horticultural Sciences Department, UF Gainesville

Fertilizer and nutrient management are essential components of
successful commercial tomato production. This article presents the
basics of nutrient management for the Jitti t c ir production systems
used for tomato in Florida.

Calibrated Soil Test: Taking the Guesswork Out of Fertilization
Prior to each cropping season, soil tests should be conducted to
determine fertilizer needs and eventual pH adjustments. Obtain an
IFAS soil sample kit from the local agricultural Extension agent for
this purpose. Commercial soil testing laboratories also are available,
however, be sure the commercial lab uses methodologies calibrated
for, and extractants suitable to Florida soils. When used with the per-
cent sufficiency philosophy, routine soil testing helps adjust fertiliz-
er applications to plant needs and target yields. In addition, the use
of the routine calibrated soil test reduces the risk of over-fertiliza-
tion. Over fertilization reduces fertilizer efficiency and increases the
risk of groundwater pollution. Systematic use of fertilizer without a
soil test may also result in crop damage from salt injury.
The crop nutrient requirements of nitrogen, phosphorus, and
potassium (designated in fertilizers as N-P205-K20) represent the
optimum amounts of these nutrients needed for maximum tomato
production (Table 1). Fertilizer rates are provided on a per-acre basis
for tomato produced on 6-ft centers. Under these conditions, there
are 7,260 linear feet of tomato row in an acre. When J.iti it4- row
spacings are used or when a significant number of drive rows are left
unplanted, it is necessary to adjust fertilizer application accordingly.
Fertilizer rates can be simply and accurately adjusted to row
spacings other than the standard spacing (6-ft centers) by expressing
the recommended rates on a 100 linear bed feet (lbf) basis, rather
than on a real-estate acre basis. For example, in a 1-acre tomato field
planted on 7-ft centers with one drive row every six rows, there are
only 5,333 lbf (6/7 x 43,560 / 7). If the recommendation is to inject
10 lbs of N per acre (standard spacing), this becomes 10 lbs of
N/7,260 lbf or 0.141bs N/100 lbf. Since there are 5,333 lbf/acre in
this example, then the adjusted rate for this situation is 7.46 lbs
N/acre (0.14 x 53.33). In other words, an injection of 10 lbs ofN to
7,260 lbf is accomplished by injecting 7.46 lbs of N to 5,333 lbf.

The optimum pH range for tomatoes is 6.0 and 6.5. This is the
range for which the availability of all the essential nutrients is high-
est. Fusarium wilt problems are reduced by liming within this range,
but it is not advisable to raise the pH above 6.5 because of reduced
micronutrient availability. In areas where soil pH is basic (>7.0),
micronutrient deficiencies may be corrected by foliar sprays.
Calcium and magnesium levels should be corrected according
to the soil test. If both elements are low, and lime is needed, then
broadcast and incorporate dolomitic limestone. Where calcium
alone is deficient, lime with "hi-cal" limestone. Adequate calcium is
important for reducing the severity of blossom-end rot. Research
shows that a Mehlich-I (double-acid) index of 300 to 350 ppm Ca
would be indicative of adequate soil-Ca. On limestone soils, add 30-
40 pounds per acre of magnesium in the basic fertilizer mix. It is
best to apply lime several months prior to planting. However, if time
is short, it is better to apply lime any time before planting than not
to apply it at all. Where the pH does not need modification, but mag-
nesium is low, apply magnesium sulfate or potassium-magnesium

sulfate with the fertilizer.
Changes in soil pH may take several weeks to occur when car-
bonate-based liming materials are used (calcitic or dolomitic lime-
stone). Oxide-based liming materials (quick lime -CaO- or dolomitic
quick lime -CaO, MgO-) are fast reacting and rapidly increase soil
pH. Yet, despite these advantages, oxide-based lime sources are
more expensive than the traditional liming materials, and therefore
are not routinely used.
The increase in pH induced by liming materials is NOT due to
the presence of calcium or magnesium. Instead, it is the carbonate
('CO3') and/or oxide ('O') part of CaCO3 and 'CaO', respectively,
that raises the pH. Through several chemical reactions that occur in
the soil, carbonates and/or oxides release OH- ions that combine
with H+ to produce water. As large amounts of H+ react, the pH
rises. A large fraction of the Ca and/or Mg in the liming materials
gets into solution and binds to the sites that are freed by H+ that have
reacted with OH-.

Fertilizer-related Physiological Disorders
Blossom-End Rot. At certain times, growers have problems with
blossom-end-rot, especially on the first one or two fruit clusters.
Blossom-end rot (BER) is basically a Ca deficiency in the fruit, but
is often more related to plant water stress than to Ca concentrations
in the soil. This is because Ca movement in the plant occurs with the
water (transpiration) stream. Thus, Ca moves preferentially to the
leaves. As a maturing fruit is not a transpiring organ, most of the Ca
is deposited during early fruit growth.
Once BER symptoms develop on a tomato fruit, they cannot be
alleviated on that fruit. Because of the physiological role of Ca in the
middle lamella of cell walls, BER is a structural and irreversible dis-
order. Yet, the Ca nutrition of the plant can be altered so that the new
fruit are not affected. BER is most effectively controlled by attention
to irrigation and fertilization, or by using a calcium source such as
calcium nitrate when soil Ca is low. Maintaining adequate and uni-
form amounts of moisture in the soil are also keys to reducing BER
Factors that impair the ability of tomato plants to obtain water
will increase the risk of BER. These factors include damaged roots
from flooding, mechanical damage or nematodes, clogged drip emit-
ters, inadequate water applications, alternating dry-wet periods, and
even prolonged overcast periods. Other causes for BER include high
fertilizer rates, especially potassium and nitrogen. High total fertil-
izer increases the salt content and osmotic potential in the soil reduc-
ing the ability of roots to obtain water, and high N increases leaf and
shoot growth to which Ca preferentially moves, by-passing fruit.
Calcium levels in the soil should be adequate when the
Mehlich-1 index is 300 to 350 ppm, or above. In these cases, added
gypsum (calcium sulfate) is unlikely to reduce BER. Foliar sprays of
Ca are unlikely to reduce BER because Ca does not move out of the
leaves to the fruit.
Gray Wall. Blotchy ripening (also called gray wall) of toma-
toes is characterized by white or yellow blotches that appear on the
surface of ripening tomato fruits, while the tissue inside remains
hard. The affected area is usually on the upper portion of the fruit.
The etiology of this disorder has not been formally established, but
it is often associated with high N and/or low K, and aggravated by
excessive amount of N. This disorder may be at times confused with
symptoms produced by the tobacco mosaic virus. Gray wall is cul-
tivar specific and appears more frequently on older cultivars. The
incidence of gray wall is less with drip irrigation where small
amounts of nutrients are injected frequently, than with systems
where all the fertilizer is applied pre-plant.
Micronutrients. For virgin, acidic sandy soils, or sandy soils
where a proven need exists, a general guide for fertilization is the
addition of micronutrients (in pounds per acre) manganese -3, cop-

per -2, iron -5, zinc -2, boron -2, and molybdenum -0.02.
Micronutrients may be supplied from oxides or sulfates. Growers
using micronutrient-containing fungicides need to consider these
sources when calculating fertilizer micronutrient needs. More infor-
mation on micronutrient use is available from the suggested litera-
ture list.
Properly diagnosed micronutrient deficiencies can often be cor-
rected by foliar applications of the specific micronutrient. For most
micronutrients, a very fine line exists between sufficiency and toxi-
city. Foliar application of major nutrients (nitrogen, phosphorus, or
potassium) has not been shown to be beneficial where proper soil
fertility is present. For more information on foliar micronutrient fer-
tilization of tomatoes, consult the Commercial Vegetable
Fertilization Guide, Circular 225E.

Fertilizer Application
Full-bed mulch with seep irrigation. Under this system, the crop
may be supplied with all of its soil requirements before the mulch is
applied (Table 1). It is difficult to correct a deficiency after mulch
application, although a liquid fertilizer injection wheel can facilitate
sidedressing through the mulch. The injection wheel will also be
useful for replacing fertilizer under the used plastic mulch for dou-
ble-cropping systems. A general sequence of operations for the full-
bed plastic mulch system is:

1. Land preparation, including development of irrigation and
drainage systems, and liming of the soil, if needed.

2. Application of "starter" fertilizer or "in-bed" mix. This should
comprise only 10 to 20 percent of the total nitrogen and potas-
sium seasonal requirements and all of the needed phosphorus
and micronutrients. Starter fertilizer can be broadcast over the
entire area prior to bedding and then incorporated. During bed-
ding, the fertilizer will be gathered into the bed area. An alter-
native is to use a "modified broadcast" technique for systems
with wide bed spacings. Use of modified broadcast or banding
techniques can increase phosphorus and micronutrient efficien-
cies, especially on alkaline (basic) soils.

3. Formation of beds, incorporation of herbicide, and application
of mole cricket bait.

4. Application of remaining fertilizer. The remaining 80 to 90 per-
cent of the nitrogen and potassium is placed in narrow bands 9
to 10 inches to each side of the plant row in furrows. The fer-
tilizer should be placed deep enough in the grooves for it to be
in contact with moist bed soil. Bed presses are modified to pro-
vide the groove. Only water-soluble nutrient sources should be
used for the banded fertilizer. A mixture of potassium nitrate (or
potassium sulfate or potassium chloride), calcium nitrate, and
ammonium nitrate has proven successful.

5. Fumigation, pressing of beds, and mulching. This should be
done in one operation, if possible. Be sure that the mulching
machine seals the edges of the mulch adequately with soil to
prevent fumigant escape.

There is equipment that will do most of the operations in steps
4 and 5 above in one pass over the field. More information on
fertilization of mulched crops is available.

Water management with the seep irrigation system is critical to
successful crops. Use water-table monitoring devices and/or ten-
siometers in the root zone to help provide an adequate water table
but no higher than required for optimum moisture. Do not fluctuate

the water table since this can lead to increased leaching losses of
plant nutrients (see the water management for tomato production
article for more information).

Mulched culture with overhead irrigation. For sandy soils, maxi-
mum production has been attained by broadcasting 100 percent of
the fertilizer in a swath 3 to 4 feet wide and incorporating prior to
bedding and mulching. Be sure fertilizer is placed deep enough to be
in moist soil. Where soluble salt injury has been a problem, a com-
bination of broadcast and banding should be used. Incorporate 30
percent to 40 percent of the nitrogen and potassium and 100 percent
of the phosphorus and micronutrients into the bed by rototilling. The
remaining nitrogen and potassium is applied in bands 6 to 8 inches
to the sides of the transplant and 2 to 4 inches deep to place it in con-
tact with moist soil. Perforation of the plastic is needed on coarse
sands where lateral movement of water through the soil is negligi-
ble. Due to a low water and nutrient efficiency, this production
method should be avoided and replaced with drip irrigation.

Mulched production with drip irrigation. Where drip irrigation is
used, drip tape or tubes should be laid 1 to 2 inches below the bed
soil surface prior to mulching. This placement helps protect tubes
from mice and cricket damage. The drip system is an excellent tool
with which to fertilize tomato. Where drip irrigation is used, apply
all phosphorus and micronutrients, and 20 percent to 40 percent of
total nitrogen and potassium preplant, prior to mulching. Apply the
remaining nitrogen and potassium through the drip system in incre-
ments as the crop develops.
Successful crops have resulted where the total amounts of N
and K20 were applied through the drip system. Some growers find
this method helpful where they have had problems with soluble-salt
bur. This approach would be most likely to work on soils with rel-
atively high organic matter and some residual potassium. However,
it is important to begin with rather high rates of N and K20 to ensure
young transplants are established quickly. In most situations, some
preplant N and K fertilizers are needed.
Suggested schedules for nutrient injections are presented in
Table 2. These schedules have been successful in both research and
commercial situations, but might need slight modifications based on
potassium soil-test indices and grower experience.
Additional nutrients can be supplied through drip irrigation if defi-
ciencies occur during the growing season.

Sources of N-P205-K20. About 30 to 50 percent of the total applied
nitrogen should be in the nitrate form for soil treated with multi-pur-
pose fumigants and for plantings in cool soil. Controlled-release
nitrogen sources may be used to supply a portion of the nitrogen
requirement. One-third of the total required nitrogen can be supplied
from sulfur-coated urea (SCU), isobutylidene diurea (IBDU), or
polymer-coated urea (PCU) fertilizers incorporated in the bed.
Nitrogen from natural organic and most controlled-release materi-
als should be considered ammoniacal nitrogen when calculating the
total amount of ammoniacal nitrogen applied.
Normal superphosphate and triple superphosphate are recom-
mended for phosphorus needs. Both contribute calcium and normal
superphosphate contributes sulfur. All sources of potassium can be
used for tomatoes. Potassium sulfate, sodium-potassium nitrate,
potassium nitrate, potassium chloride, monopotassium phosphate,
and potassium-magnesium sulfate are all good K sources. If the soil
test predicted amounts of K20 are applied, then there should be no
concern for the K source or its associated salt index.

Sap Test and Tissue Analyses
While routine soil testing is essential in designing a fertilizer
program, sap tests and/or tissue analyses reveal the actual nutrition-

al status of the plant. Therefore these tools complement each other,
rather than replace one another.
Analysis of tomato leaves for mineral nutrient content can help
guide a fertilizer management program during the growing season or
assist in diagnosis of a suspected nutrient deficiency. Tissue nutrient
norms are presented in Table 3. Growers with drip irrigation can
obtain faster analyses for N or K by using a plant sap quick test.
Several kits have been calibrated for Florida tomatoes. Interpretation
of these kits is provided in Table 4. More information is available on
plant analysis.
For both nutrient monitoring tools, the quality and reliability of
the measurements are directly related with the quality of the sample.
A leaf sample should contain at least 20 most recently, fully devel-
oped, healthy leaves. Select representative plants, from representa-
tive areas in the field.

Supplemental Fertilizer Applications
In practice, supplemental fertilizer applications allow vegetable
growers to numerically apply fertilizer rates higher than the standard
IFAS recommended rates when warranted by growing conditions.
The two main growing conditions that may require supplemental
fertilizer applications are leaching rains and extended harvest peri-
ods. Applying additional fertilizer under the following three circum-
stances is part of the current IFAS fertilizer recommendations.
Supplemental N and K fertilizer applications may be made under
three circumstances:
1. For tomato crops grown with or without plastic mulch and with
seepage irrigation, a 30 lbs/acre of N and /or 20 lbs/acre of K20
supplemental application is allowed after a leaching rain. A
leaching rain occurs when it rains at least 3 inches in 3 days, or
4 inches in 7 days. In this case, supplemental fertilizer applica-
tion may be done using a fertilizer wheel.

2. For tomato grown with drip irrigation and one of the IFAS rec-
ommended irrigation scheduling methods, a supplemental fer-
tilizer application is allowed when nutrient levels in the leaf or
in the petiole fall below the sufficiency ranges. In this case, the
supplemental amount allowed is 2.5 lbs/A/day for N and/or 3.0
lbs/A/day for K20 for one week.

3. Supplemental fertilizer applications are allowed when, for eco-
nomical reasons, the harvest period has to be longer than the
typical harvest period. When the results of tissue analysis
and/or petiole testing are below the sufficiency ranges, a sup-
plemental 30 lbs/acre N and/or 20 lbs/acre of K20 may be made
for each additional harvest for production with seep irrigation.
For drip-irrigated tomato, the supplemental fertilizer applica-
tion is 2.5 lbs/A/day for N and/or 3.0 lbs/A/day for K20 until
the next harvest. A new leaf analysis and/or petiole analysis is
required to document the need for additional fertilizer applica-
tion for each additional harvest.

Levels of Nutrient Management for Tomato Production
Based on the growing situation and the level of adoption of the
tools and techniques described above, dit,!tcic!- levels of nutrient
management exist for tomato production in Florida. Successful pro-
duction requires management levels of 3 or above (Table 5).

Suggested Literature
Hochmuth, G. 1994. Plant petiole sap-testing for vegetable crops.
Univ. Fla. Coop. Ext. Circ. 1144, http://edis.ifas.ufl.edu/cv004

Hochmuth, G. J., and A. G. Smajstrla. 1998. Fertilizer application
and management for micro (drip) irrigated vegetables in Florida.
Univ. Fla. Coop. Ext. Serv. Circ. 1181, http://edis.ifas.ufl.edu/cvl41

Hochmuth, G., D. Maynard, C. Vavrina, and E. Hanlon. 1991. Plant
tissue analysis and interpretation for vegetable crops in Florida.
Univ. Fla. Coop. Ext. Serv. Special Series Public. SS-VEC-42.

Hochmuth, G. J. and E. A. Hanlon. 2000. IFAS standardized fertil-
ization recommendations for vegetable crops. Univ. Fla. Coop. Ext.
Circ. 1152, http://edis.ifas.ufl.edu/cv002

Maynard, D.N., and G.J. Hochmuth. 1997. Knott's Handbook for
vegetable growers. 4th ed. Wiley Interscience, New York.

Simonne, E.H. and G.J. Hochmuth. 2002. Soil and fertilizer man-
agement for vegetable production in Florida, pp.3-14. In: S.M.
Olson and D.N. Maynard (eds.), Vegetable Production Guide for
Florida, Vance Publishing, Lenexa, KS.

Simonne, E., D. Studstill, B. Hochmuth, T. Olczyk, M. Dukes, R.
Munoz-Carpena, andY. Li. 2002. Drip irrigation: The BMP era -An
integrated approach to water and fertilizer management in Florida,
EDIS HS917, http://edis.ifas.ufl.edu/HS172.

Simonne, E.H., C.M. Hutchinson, M.D. Dukes, G.J. Hochmuth, and
R.C. Hochmuth. 2003. Update and outlook for 2003 BMP program
for vegetable crops, EDIS HS916, http://edis.ifas.ufl.edu/HS170.

Simonne, E.H. and G.J. Hochmuth. 2003. Principles of irrigation
and fertilization management for vegetable crops grown in Florida
in the BMP era: Introduction. EDIS HS897,
http://edis.ifas.ufl.edu/HS1 54.

(tables 1-5 on following pages)

Table 1. Fertility recommendations for mulched tomatoes on irrigated soils testing very low
in phosphorus and potassium.

Nutrient Supplemental
requirements applications

Number of lbs/Ay lbs/A Number of
Soil type expected harvests N-P205-K20 N-P20O-K20 applications

Mineral 2-3 200-150-225 30-0-20 0-2

z In case of incidental flood, sidedressing to replenish nitrogen and potassium can be
accomplished by the use of a liquid fertilizer injection wheel.
Y Approximately 7,200 linear bed feet of crop per acre (43,560 square feet); based on
Mehlich 1 soil tests results.

Table 2. Schedules for N and K20 injection for mulched tomato on soils testing low in K.
Crop development Injection (lb/A/day)z

stage weeks N K20

1 2 1.5 1.5

2 2 2.0 2.0

3 7 2.5 3.0

4 1 2.0 2.0

5 1 1.5 1.5

z Total nutrients applied are 200 lb N and 225 lb K20 per acre (7,260 linear bed feet).
These injection programs assume no N or K preplant. If 20% of N and K are applied
preplant in the bed, then first two weeks of injection can be reduced. IFAS
recommendations also allow for supplemental fertilizer applications after a leaching
rain, when plant nutritional status is low, or with extended harvest schedules.

Table 3. Deficient, adequate, and excessive nutrient concentrations for tomatoes [most-recently-matured (MRM) leaf (blade plus petiole)].

N P K Ca Mg S

Fe Mn Zn

B Cu Mo

--------------------------- % ----------------------------

Tomato MRMz 5-leaf Deficient <3.0 0.3 3.0 1.0 0.3 0.3
leaf stage

Adequate 3.0 0.3 3.0 1.0 0.3 0.3
range 5.0 0.6 5.0 2.0 0.5 0.8

High >5.0 0.6 5.0 2.0 0.5 0.8

MRM First Deficient <2.8 0.2 2.5 1.0 0.3 0.3
leaf flower

Adequate 2.8 0.2 2.5 1.0 0.3 0.3
range 4.0 0.4 4.0 2.0 0.5 0.8

High >4.0 0.4 4.0 2.0 0.5 0.8

Toxic (>)

MRM Early Deficient <2.5 0.2 2.5 1.0 0.25 0.3
leaf fruit set

Adequate 2.5 0.2 2.5 1.0 0.25 0.3
range 4.0 0.4 4.0 2.0 0.5 0.6

High >4.0 0.4 4.0 2.0 0.5 0.6

Toxic (>)

Tomato MRM First ripe Deficient <2.0 0.2 2.0 1.0 0.25 0.3
leaf fruit

Adequate 2.0 0.2 2.0 1.0 0.25 0.3
range 3.5 0.4 4.0 2.0 0.5 0.6

High >3.5 0.4 4.0 2.0 0.5 0.6

MRM During Deficient <2.0 0.2 1.5 1.0 0.25 0.3
leaf harvest

Adequate 2.0 0.2 1.5 1.0 0.25 0.3
range 3.0 0.4 2.5 2.0 0.5 0.6

High >3.0 0.4 2.5 2.0 0.5 0.6

'MRM=Most recently matured leaf.

----------------------------- ppm ------- ------- -------

40 30 25 20 5 0.2

40 30 25 20
100 100 40 40

100 100 40 40

40 30 25 20

40 30 25 20
100 100 40 40

100 100 40 40

1500 300 250

40 30 20 20

40 30 20 20
100 100 40 40

100 100 40 40


40 30 20 20

40 30 20 20
100 100 40 40

100 100 40 40

40 30 20 20

40 30 20 20
100 100 40 40

100 100 40 40

5 0.2

5 0.2

Table 4. Suggested nitrate-N and K concentrations in fresh petiole sap for tomatoes.

Sap concentration (ppm)

Stage of growth

First buds

First open flowers

Fruits one-inch diameter

Fruits two-inch diameter

First harvest

Second harvest















Table 5. Progressive levels of nutrient management for tomato production
Nutrient Management Description

Level Rating

0 None Guessing

1 Very low Soil testing and still guessing

2 Low Soil testing and implementing 'a' recommendation

3 Intermediate Soil testing, understanding IFAS recommendations, and correctly implementing them

4 Advanced Soil testing, understanding IFAS recommendations, correctly implementing them, and
monitoring crop nutritional status

5 Recommended Soil testing, understanding IFAS recommendations, correctly implementing them,
monitoring crop nutritional status, and practice year-round nutrient management
and/or following BMPs (including one of the recommended irrigation scheduling
SThese levels should be used together with the highest possible level of irrigation management

Weed Control in Tomato

William M. Stall' and James P. Gilreath2
1Horticultural Sciences Department, Gainesville, 2Gulf Coast
Research & Education Center, Bradenton

Although weed control has always been an important compo-
nent of tomato production, its importance has increased with the
introduction of the sweet potato whitefly and development of the
associated irregular ripening problem. Increased incidence of sever-
al viral disorders of tomatoes also reinforces the need for good weed
control. Common weeds, such as the difficult to control nightshade,
and volunteer tomatoes (considered a weed in this context) are hosts
to many tomato pests, including sweet potato whitefly, bacterial
spot, and viruses. Control of these pests is often tied, at least in part,
to control of weed hosts. Most growers concentrate on weed control
in row middles; however, peripheral areas of the farm may be neg-
lected. Weed hosts and pests may flourish in these areas and serve as
reservoirs for re-infestation of tomatoes by various pests. Thus, it is
important for growers to think in terms of weed management on all
of the farm, not just the actual crop area.
Total farm weed management is more complex than row mid-
dle weed control because several .i rttci c-ir sites, and possible herbi-
cide label restrictions are involved. Often weed species in row mid-
dles differ from those on the rest of the farm, and this might dictate
,Jittci!ir approaches. Sites other than row middles include road-
ways, fallow fields, equipment parking areas, well and pump areas,
fence rows and associated perimeter areas, and ditches.
Disking is probably the least expensive weed control procedure
for fallow fields. Where weed growth is mostly grasses, clean culti-
vation is not as important as in fields infested with nightshade and
other disease and insect hosts. In the latter situation, weed growth
should be kept to a minimum throughout the year. If cover crops are
planted, they should be plants which do not serve as hosts for toma-
to diseases and insects. Some perimeter areas are easily disked, but
berms and field ditches are not and some form of chemical weed
control may have to be used on these areas. We are not advocating
bare ground on the farm as this can lead to other serious problems,
such as soil erosion and sand blasting of plants; however, where
undesirable plants exist, some control should be practiced, if practi-
cal, and replacement of undesirable species with less troublesome
ones, such as bahiagrass, might be worthwhile.
Certainly fence rows and areas around buildings and pumps
should be kept weed-free, if for no other reason than safety.
Herbicides can be applied in these situations, provided care is exer-
cised to keep it from drifting onto the tomato crop.
Field ditches as well as canals are a special consideration
because many herbicides are not labeled for use on aquatic sites.
Where herbicidal spray may contact water and be in close proximi-
ty to tomato plants, for all practical purposes, growers probably
would be wise to use Diquat only. On canals where drift onto the
crop is not a problem and weeds are more woody, Rodeo, a systemic
herbicide, could be used. Other herbicide possibilities exist, as list-
ed in Table 1. Growers are cautioned against using Arsenal on toma-
to farms as tomatoes are very sensitive to this herbicide. Particular
caution should be exercised if Arsenal is used on seepage irrigated
farms as it has been observed to move in some situations.
Use of rye as a windbreak has become a common practice in
the spring; however, in some cases, adverse effects have resulted. If
undesirable insects such as thrips buildup on the rye, contact herbi-
cide can be applied to kill it and eliminate it as a host, yet the

remaining stubble could continue serving as a windbreak.
The greatest row middle weed control problem confronting the
tomato industry today is control of nightshade. Nightshade has
developed varying levels of resistance to some post-emergent herbi-
cides in .itt-ici-r areas of the state. Best control with post-emer-
gence (directed) contact herbicides are obtained when the night-
shade is 4 to 6 inches tall, rapidly growing and not stressed. Two
applications in about 50 gallons per acre using a good surfactant is
usually necessary.
With post-directed contact herbicides, several studies have
shown that gallonage above 60 gallons per acre will actually dilute
the herbicides and therefore reduce efficacy. Good leaf coverage can
be obtained with volumes of 50 gallons or less per acre. A good sur-
factant can do more to improve the wetting capability ofa ipi I-. ri, iio
can increasing the water volume. Many adjuvants are available com-
mercially. Some adjuvants contain more active ingredient then oth-
ers and herbicide labels may specify a minimum active ingredient
rate for the adjuvant in the spray mix. Before selecting an adjuvant,
refer to the herbicide label to determine the adjuvant specifications.

Postharvest Vine Dessication
Additionally important is good field sanitation with regard to
crop residue. Rapid and thorough destruction of tomato vines at the
end of the season always has been promoted; however, this practice
takes on new importance with the sweet potato whitefly. Good
canopy penetration of pesticidal sprays is difficult with convention-
al hydraulic sprayers once the tomato plant develops a vigorous
bush due to foliar interception of spray droplets. The sweet potato
whitefly population on commercial farms was observed to begin a
dramatic, rapid increase about the time of first harvest in the spring
of 1989. This increase appears to continue until tomato vines are
killed. It is believed this increase is due, in part, to coverage and
penetration. Thus, it would be wise for growers to continue spraying
for I- t!l, until the crop is destroyed and to destroy the crop as
soon as possible with the fastest means available. Both diquat and
paraquat are now labeled for postharvest dessication of tomato
vines. The labels differ slightly, follow the label directions.
The importance of rapid vine destruction can not be over
stressed. Merely turning off the irrigation and allowing the crop to
die will not do; application of a desiccant followed by burning is the
prudent course.

Chemical Weed Controls: tomatoes

Time of Application Rate (Ibs. AlAcr
Heb Labeled Crops torop Mineral Muck
Cthodem Tomatoes Posternergence 0.9-.125
(Salect 2 EC)
RWlmrk: Poelernergence conto of actively going annal grass. Apply at 5-8 I cazacre. Use
high rate Lnder heavy gras pressure andtYor vei grasses are at maximum heigL Always use a
crop oil concentrate at 1% vv in ihe finished spray volume. Do not apply within 20 days of torrlo
DCPA (Dacthal W-75) Established Tomatoes Pasitransplanlng after 6.,080 -
crop establishment (non-
Rlmarks Controls germinating annuals, Apply to weed-free sail 6 to 8 weeks after crop is
established and growing rapidly or to moist soil in row muddles after crop establlisment N4oe label
precautions of replanting non-ragistered crops within 8 months.
Dlquat (Reone) Tomrato Vine After final hervest 0.375 -
Roarta Special Local Needs (24c) label foi use for bumdown of lonato virne after final haruesl
Applications of 1.5 pta. material pe acre In 80 to 120 gal of water is labeled. Add 18 to 32 oz of a
non-ionic spreader per 100 gals. of spray mix. Thorough oerage of vnes Is required to Insure
maximum burdown.
Diqual Tomato Preransplant 0.5
(Reglone) Postemeence directed-
shielded in row middles
Remarks: Diquat can be applied as a post-directed applicallon to row middles either prior to
Transplanting or as a post-diected hooded spray applica;ion to row middles when transplants are
well established. Apply 1 qt of Dquat in 20-50 gallons of water per treated acre when weeds are 2-
4 inches in height. Do not exceed 25 psi spray pressure, A maximum of 2 applications can be
made during the growing season. Add 2 pts nan-ionic surfaant per 100 gals spray mix, ODqua
will be inactivated if muddy or dirty water Is used in spray mix. A 30 day PHI is in effect. Labal is a
special local needs label for Florida only.
Haloulfuron Tomatoes Pre-ransplan 0.024 0,036
(Sandea) Poelemergtence
Row mlddles
Rema~s: A total of 2 applications of Sandee may be applied as either one pre-transplanI Sol
surface trBambnt at 0.5-0.75 oz. product one ovr-thel -top application 14 days after tranplanting
at 0,5-0,75 oz. product and/or postemergence application(s) of upto 1 oz, product (0.047 Ib ai)to
row mlddles. A 30-day PHI wil be observed. For posternergence and rw middle applications, a
surf cIant should be added to the spray mix,
MCDS (Enquik) Tomatoes Poslemergence 5 a gals. -
directed/shielded in row
Remarks Controls many emerged broadleaf weeds. Weak on grasses. Apply 5 to 8 gallons of
Enquak in 20 to 50 gallons of total spray volume per treated acre, A non-ionic surfactant should be
added at 1 to 2 pints per 100 gallons, Enqulk is severely corrosive to nylon. Non-nylon plastic and
316-L stainless stel are recommended for application equipment Read the precautionary
stateenets before use. Follow all restrictions on the label.
S-Maeotacnhor Tomnaloe Preiransplani 1- 1. -
(Duel Magnum) Row mkidles

Chemical Weed Controls: tomatoes (continued)

Time of Application Rate (Ibs. A./Acre)
Herbicide Labeled Crops Mineral Muck
Remarkw: Apply Dual Magnum preplant non-.icrporated to the top of a pressed bed as the st
step prior to lying plastic, May also be used to tral row-middles. Label Flasa ar 1,0-133 pts/A If
organic marlter is lees Ihan 3%. Research has shown that the 1-33 pt may be too high in soma
Florida aorls xcpt in row middles. Good rults have been seen at 0.6 pta to 1.0 pinls especially
in lank mi situations under mulch, Use on a rial basis.
Maribuzin Tomatoes Postemergence 0.25 0.5 -
Sencor DF) (Saenco 4) Posflransplanting after
Remuas: Controls small emerged weeds after transplants are established direct-seeded plants
reach 5 to 6 true leaf stage. Apply in single or multiple applications with a minimum of 14 days
between Ireatments and a maximum of 1.0 lb ai/are within a crop season. Avoid applications or 3
days following cool, wet or cloudy weather to reduce possible crop injury-
Metribuzin Tomanes Directed pray i row 0.25 1.0 -
(Secor DF) (Senoor 4) midfdes
Remarks Apply in singe or muNliple applications with a lmum nof 14 days between tratmenls
and maximum of 1.0 Ib aolcre within crap season. Avoid applications for 3 days following cool, wet
or cloudy wether Io mrduce possible crp injry. Label state control of mary annual grasses and
broaaleaf weeds including, lumbequarter, fall panicum, amaranth p., Florida puisty. common
ragweed, icktdepod, and spotted spu .
Napopamld Tomatoes Preptant incorporated 1.0 2,0
(Oevrinol 50DF)
Remarks; Apply to well worked so that is dry enough to permit thorough icorporalion to a deplh of
1 to 2 Inches, Incorporate same day as applied. For dlrect-seeded or transplanled tomatoes.
Napropamid Tomaloee Surface tralment 2.0
(Devrinol 50DF)
Remar- Controls germlnatg annuals. Apply to bed top after bedding bul bekaru plasic
applicaion. Rainfall or overheed-irrigate suficient to wel so 1 Inch in depth should follow treatmenl
within 24 hours. May be applied to row mkddles between mulched beds. A special Local Need
24(c) Label for Florida, Label late control of weeds including Texas panlcum, pigweed, purtne,
Florida pusley. and signagrass.
Oxyfluorfen Tomatoes Fallow bed 0.25 0.5
(Goal 2XL)
Remarkt: Must havb a 30 day Irealment-planling interval. Apply as a preemergence broadcast or
banded trealent at 1-2 pt/A to prafrmed beds. Mukl may be applied any lime during the 30-day
Paaqual Tomatoes Premergmeen 0.62 0.94 -
(GOramoone Extra) Pretransplen
(Gramoxone Max)
Remarks: Control emerged weeds. Us a non4on spreader and thorough wet weed foliage.
Paraqual Tomatoes Post directed spray in 0.47
{Grarnmxone Extra) row middle
(Gramoxone Max)
Remarks: Controls emerged weeds. Direct spray over merged weeds 1 to 6 indies tall in row
middles between mulched beds. Use a non-ionic spreader. Lis low pressure and shields 1o control
drift Do not apply nmoW than 3 times per season.
Paraqual Tomato Posttarvest


Chemical Weed Controls: tomatoes (continued)
r I

(Oremanone Extra)
(Gramomaon Extra)

Labeled Crops

Time of Application
to Crop

Rale (lbs. AI.JAcre)
Mineral Muck

Remarks: Broadmcat spry ove the top of plants after last hardest. Label for Boe states use of 1.5,
2.0 ptA whri Gramoxrne label b from 2-3 pt. Uas a nonlonic surfactwnt at I pt/l00 gabs it I qf100
gals spray solution. ThoBough coverage Ia required to ensure maximum herbicide bundown. Do not
ue treated crop for human or animal consumption.

Pelargnic Acid

Fruiting Vegetabe


Remarks: Product is a contact, nonselective, folar applied herbicide. There is no residual control,
May be tank mixed with several soil residual compounds. Consult the label for rates. Has
greenhouse and growth structure label.
FmsuHflr Tomal Postlramptlent end 026 0S. -
(Mtrix) diecsdd-1aw middles
Ramrku Matrix may be applied preenurgence (seeded), poaemergence, poaSransplant and
applied directed to row mide. May be applied at 1-2 o product (0,25-0,5 oz al) in single or
sequential applications. A aximmn of 4 az. product per acre per year may be applied. For post
(weed) application. use a non-lonc surfct at at a rate of 0.25% vv. for preemergece (weed)
control, Matrix must be activated in the smol with sprinkler irrigu or rainfall. Check crop roallnal
puidelines on label.

Sethoxydin (PDasl)



0.18-0.28 -

Remarks: Controls actively growing grass weeds. A total of 42 pis. product per acr may be apopled
in one season. Do not apply wlthin 20 days of larvestl Apply in 5 to 20 gallons of water adding 2 pis,
of oil ooncrntrate per are. Unsatisfactory results may occur If applied to grasses under stws. Use
0.188 Ib ai (1 pt) to seedling grasss and up to 0-28 Ib ai (12 pts.) to perennial grasses emerging
from rhlznes etc. Consult label for grsr species and growth stage for best control.

(Treflan HFP)
(Trelan TR-10)
(Trllin) (Trilhi 100)
(TrIflLuran 480)
(Trflurain 4EC)
(Trlluamin IF)

Tomatoes PretranBplanl
(excepl Dada County) incorporated

Ratetwks: Conlrols grmninating annuas. Inonporate 4 Inches or less wihin 8 hours of application.
Reuit In Florida are eratc on ~lls with low orgeanc maler and chay cont~bs Note l
precautllns of planting non-registeed crops within 5 months. Do not apply after transplanting.

Treflan HFP)
(Trafan TR-10)
(Trlin) (Trilin 100)
(Triluralln 480)
{Trifluralin 4EC)
(Trifturalin HF)
Remarks: For
between the ro

tomatoes (except Dade

Post directed

direct-seeded tomatoes, apply at blacking or h inning as a directed spray to the soil
vs and incororals.

3.10% vvv


Chemical Disease Management for Tomato. Tom Kucharek, Plant
Pathology Department, Gainesville

Chemical Maximum Rate/Acrel Minimum Pertinent Diseases Select Remarks
Days to
Application Crop Harvest

**For best possible chemical control of bacterial spot with a copper fungicide, a maneb or mancozeb fungicide must be
tank-mixed with the copper fungicide in the spray tank.

Ridomil Gold EC 2 pts/trtd acre 3 pts/trtd acre Pythium diseases See label for use at and
after planting.

Kocide 101, Blue 4 lbs 1 Bacterial spot
Shield or Champion Bacterial speck

Kocide LF, Blue 5 a pts 1 Bacterial spot
Shield 3L, or Bacterial Speck
Champion FL's

Kocide 2000 53.8DF 3 lbs. 1 Bacterial spot
Bacterial speck

Champ 4.6 or Kocide 2 b pts 1 Bacterial spot
4.5 LF FLs ___ Bacterial speck

Basicop or Basic 4 lbs 1 Bacterial spot
Copper 53

Cuprofix Disperss 6 lbs 1 Bacterial spot
36.9 DF Bacterial speck
Cuprofix Disperss 7.25 lbs 5 Bacterial spot See label for avoiding
MZ Disperss Bacterial speck excess use of mancozeb

Manex 4F 2.4 qts 16.8 qts 5 Early & late blights, Field & greenhouse use
Gray leaf spot,
Bacterial spot1

Kocide or 4 lbs 2 Bacterial spot
Blueshield DF's __ _Bacterial speck

Maneb 80 WP 3 lbs 21 lbs 5 Same as Manex 4F Field & greenhouse use

Dithane F45 or 2.4 pts 16.8 qts 5 Same as Manex 4F
Manex II 4 FLs

Dithane, Penncozeb 3 lbs 21 lbs 5 Same as Manex 4F
or Manzate DF's

Echo 720 6 FL 3 pts 20 pts 0 Early and late blight, Use higher rates at fruit
Gray leaf spot, Target set and lower rates before
spot fruit set.

Maneb 75DF 3 lbs 22.4 lbs 5 Same as Manex 4F Field & greenhouse use

Echo 90 DF 2.3 Ibs 16.7 lbs 0 Early and late blight, Use higher rates at fruit
Gray leaf spot, Target set and lower rates before
spot fruit set.

Chemical Maximum Rate/Acrel Minimum Pertinent Diseases Select Remarks
Days to
Application Crop Harvest
Bravo 500, Echo Gray leaf spot, Target set and lower rates before
500, or GK Chloro spot fruit set.
Gold 4.17 FL's

Ridomil Bravo 81W 3 lbs 2 Early and late blight, Limit is 4 appl/crop
Gray leaf spot, Target

Ridomil MZ68WP2 2 lbs 8 lbs 5 Late blight Limit is 3 appl/crop

JMS Stylet Oil 3 qts NTL Potato Virus Y, See label for specific info
Tobacco Etch Virus on appl. technique (e.g.
use of 400 psi spray

Ridomil/Copper 2.0 lbs See label 14 Late blight Limit is 3 appl/crop.

Sulfur 1 Powdery mildew

Aliette WDG 5 lbs 20 lbs 14 Phytophthora root rot Using potassium
carbonate or Diammonium
phosphate, the spray of
Aliette should be raised to
a pH of 6.0 or above when
applied prior to or after
copper fungicides.

Bravo Ultrex 82.5 2.75 lbs 18.3 lbs 0 Early and Late blights, Use higher rates at fruit
WDG Gray leafs pot, Target set.
spot, Botrytis,
Rhizoctonia fruit rot

Bravo Weather Stik 2 3/4 pts 20 pts 0 Same as Bravo Ultrex Use higher rates at fruit
6 FL ____ set

Quadris 2.08 FL 6.2 fl oz 37.2 fl oz 0 Early blight, late Do not make more than 2
blight, Sclerotinia sequential appl. with
Quadris. Limit is 6 appl.
Alternate with compounds
other than Cabrio

Cabrio 2.09 FL 16 fl oz 96 fl oz 0 Same as Quadris Limit is 6 appl./crop.
Alternate with compounds
other than Quadris.

Botran 75W 1 lb 4 lbs 10 Botrytis Greenhouse tomato only.
Limit is 4 applications.
Seedlings or newly set
transplants may be
Buckeye rot, Early
Gavel 75 DF 2.0 lbs 16 lbs 5 blight, gray leaf spot,
late blight, & leaf
Note that a 30 day plant
Nova 40 W 4 oz 1.24 lbs 0 Powdery mildew back restriction exists.

Chemical Maximum Rate/Acrel Minimum Pertinent Diseases Select Remarks
Days to
Application Crop Harvest

Exotherm Termil 1 can/1000 2 Botrytis, Leaf mold, Greenhouse use only.
sq. ft. Late & Early blights, Allow can to remain
Gray leaf spot overnight and then
ventilate. Do not use when
greenhouse temperature is
above 75F.

Do not use highest
Actigard 50 WG 1/3-3/4 oz 4 oz 14 Bacterial spot labeled rate in early
Bacterial Speck sprays to avoid a delayed
onset of harvest. Begin
with 1/3 oz rate and
progressively increase the
rate as instructed on the
label. Limit is 6
appl./crop/season. Do not
exceed a concentration of
oz/100 gal. of spray
mix. Begin spray program
before occurrence of

ManKocide 61.1 DF 5.3 lbs 112 lbs 5 Bacterial spot
S Bacterial speck

'When tank mixed with a copper fungicide.

2Do not exceed limits of mancozeb active ingredient when using more than one product ( Dithane, Penncozeb, Manex II, or

Selected insecticides approved for use on insects attacking tomatoes.
S.E. Webb, Entomology and Nematology Department, UF, Gainesville.
Chemical Name REI Days to Insects Notes
S(hours) Harvest
Admire 2F 12 21 aphids, Colorado potato beetle, Most effective if
(imidacloprid) flea beetles, thrips (foliar applied to soil at
feeding thrips only), whiteflies transplanting.
*Agri-Mek 0.15EC 12 7 Colorado potato beetle, Do not make more
(abamectin) Liriomyza leafminers, spider than 2 sequential
mite, tomato pinworms, tomato applications. Do not
russet mite apply more than
0.056 Ib ai per acre
per season.
*Ambush 2EC, 25W 12 up to day of beet armyworm, cabbage Do not apply more
(permethrin) harvest looper, Colorado potato beetle, than 1.2 Ib active
granulate cutworms, ingredient per acre
hornworms, southern per season. Not
armyworm, tomato fruitworm, recommended for
tomato pinworm, vegetable control of vegetable
leafminer leafminer in Florida.
*Asana XL 0.66EC 12 1 beet armyworm (aids in Not recommended
(esfenvalerate) control), cabbage looper, for control of
Colorado potato beetle, vegetable leafminer
cutworms, flea beetles, in Florida. Do not
grasshoppers, hornworms, apply more than
potato aphid, southern 0.5 Ib ai per acre
armyworm, tomato fruitworm, per season.
tomato pinworm, whiteflies,
yellowstriped armyworm
Assail 70WP 12 7 aphids, Colorado potato beetle, Begin applications
(acetamiprid) whiteflies for whiteflies when
first adults are
noticed. Do not
apply more than 4
times per season or
apply more often
than every 7 days.
Do not apply to a
crop that has been
already treated with
imidacloprid or
thiamethoxam at
Avaunt 12 3 beet armyworm, hornworms, Do not apply more
(indoxacarb) loopers, southern armyworm, than 14 ounces of
tomato fruitworm, tomato product per acre
pinworm per crop. Minimum
spray interval is 5

Azatin XL Plus 4 0 aphids (suppression), Use with oil for
azadirachtinn) armyworms, beetles, leafminers. Insect
caterpillars, cutworms, growth regulator
leafhoppers, leafminers, and feeding
loopers, thrips, whiteflies deterrent.
Bt 4 see label armyworms, cabbage looper,
(Bacillus thuringiensis) corn earworm, cutworms,
Agree, Biobit HP, hornworms, loopers, tomato
Crymax, Dipel DF, 12(1) fruitworm
Javelin WG, Lepinox
WDG(1', Xentari
*Baythroid 2 12 0 beet armyworm (1), cabbage (1) Ist and 2nd
(cyfluthrin) looper, Colorado potato beetle, instars only
dipterous leafminers, European
corn borer, flea beetles, (2) suppression
hornworms, potato aphid, Do not apply more
southern armyworm (1), stink than 0.26 Ib ai per
bugs, tomato fruitworm, tomato acre per season.
pinworm, variegated cutworm ,
western flower thrips, whitefly Maximum number
(2) of applications: 6.
*Capture 2EC 12 1 aphids, armyworms, corn Make no more than
(bifenthrin) earworm, cutworms, flea 4 applications per
beetles, grasshoppers, mites, season. Do not
stink bug spp., tarnished plant make applications
bug, thrips, whiteflies less than 10 days
Checkmate TPW, 0 0 tomato pinworm For mating
TPW-F disruption -
(pheromone) See label.
Confirm 2F 4 7 armyworms, black cutworm, Do not apply more
(tebufenozide) hornworms, loopers than 1.0 Ib ai per
acre per season.
Product is a slow-
acting IGR and will
not kill larvae
Courier 12 7 whitefly nymphs Apply when a
(buprofezin) threshold is
reached of 5
nymphs per 10
leaflets from the
middle of the plant.
Product is a slow-
acting IGR that will
not kill nymphs
immediately. No
more than 2
applications per
season. Allow at
least 28 days
applications. See
label for plantback

*Danitol 2.4 EC

3 days, or 7
if mixed
Monitor 4

beet armyworm, cabbage
looper, fruitworms, potato
aphid, silverleaf whitefly, stink
bugs, thrips, tomato pinworm,
twospotted spider mites,
yellowstriped armyworm

Use alone for
control of
fruitworms, stink
bugs, twospotted
spider mites, and
armyworms. Tank-
mix with Monitor 4
for all others,
especially whitefly.
Do not apply more
than 0.8 Ib ai per
acre per season.
Do not tank mix
with copper.

Dimethoate 4 EC, 48 7 aphids, leafhoppers, leafminers Will not control
2.67 EC organophosphate-
(dimethoate) resistant
*Diazinon 4 E; *50 W; 24 1 foliar application: aphids, beet Will not control
*14 G; *5 G armyworm, banded cucumber organophosphate-
(diazinon) beetle, Drosophila, fall resistant
armyworm, dipterous leafminers. Do not
leafminers, southern armyworm apply more than
soil application at planting: five times per
cutworms, mole crickets, season.
Extinguish 4 0 fire ants Slow-acting IGR
((S)-methoprene) (insect growth
regulator). Best
applied early spring
and fall where crop
will be grown.
Colonies will be
reduced after three
weeks and
eliminated after 8 to
10 weeks. This is
the only fire ant bait
labeled for use on
cropland. May be
applied by ground
equipment or
Fulfill 12 0 green peach aphid, potato Do not make more
(pymetrozine) aphid, suppression of whiteflies than two
applications. 24(c)
label for growing
transplants also.


beet armyworm, cabbage
looper, Colorado potato beetle,
cutworms, fall armyworm, flea
beetles, grasshoppers, green
and brown stink bugs.
hornworms, leafminers,
leafhoppers, lygus bugs, plant
bugs, southern armyworm,
tobacco budworm, tomato

Not recommended
for vegetable
leafminer in Florida.
Do not make
applications less
than 7 days apart.
Do not apply more
than 0.3 Ib ai per
acre per season.

fruitworm, tomato pinworm, true
armyworm, yellowstriped
armyworm. Aides in control of
aphids, thrips and whiteflies.
Kelthane MF 4 12 2 mites Do not apply more
(dicofol) than twice a year or
more than 1.6 pt.
per season.
Knack IGR 12 14 immature whiteflies Apply when a
(pyriproxyfen) threshold is
reached of 5
nymphs per 10
leaflets from the
middle of the plant.
Product is a slow-
acting IGR that will
not kill nymphs
immediately. Make
no more than two
Kryocide 96 WP; 12 14 blister beetle, cabbage looper, Minimum of 7 days
Prokil Cryolite 96 Colorado potato beetle larvae, between
(cryolite) flea beetles, hornworms, tomato applications. Do not
fruitworm, tomato pinworm apply more than 64
Ib. per acre per
*Lannate LV, *SP 48 1 aphids, armyworms, beet Do not make more
(methomyl) armyworm, fall armyworm, than 16
hornworms, loopers, southern applications per
armyworm, tomato fruitworm, crop.
tomato pinworm, variegated
Malathion 5 EC, 12 1 aphids, Drosophila, mites Can be used in
57 EC, 8 EC greenhouse.

*Monitor 4EC 48 7 thrips (North Florida only), (1) Use as tank mix
(methamidophos) whiteflies(') with a pyrethroid for
whitefly control.
[24(c) labels] Do not apply more
than 10 pt. per
acre, or 18 pt. per
acre in North
Florida per season.
M-Pede 49% EC 12 0 aphids, leafhoppers, mites,
(Soap, insecticidal) plant bugs, thrips, whiteflies




Neemix .25 4 0 aphids, armyworms
azadirachtinn) hornworms, psyllids, Colorado
potato beetle, cutworms,
Neemix 4.5 12 0 leafminers, loopers, tomato
fruitworm (corn earworm),
tomato pinworm, whiteflies
NoMate MEC TPW 0 0 tomato pinworm For mating
(pheromone) disruption -
See label.
Phaser 3EC, 50 WP 24 2 aphids, blister beetle, cabbage Do not exceed a
endosulfann) looper, Colorado potato beetle, maximum of 3.0 Ib
flea beetles, hornworms, stink active ingredient
bugs, tomato fruitworm, tomato per acre per year or
russet mite, whiteflies, apply more than 6
yellowstriped armyworm times. Can be used
in greenhouse.
Platinum 12 30 aphids, Colorado potato Soil application.
(thiamethoxam) beetles, flea beetles, See label for
leafminers, whiteflies rotational
*Pounce 3.2 EC 12 0 beet armyworm, cabbage Do not apply to
(permethrin) looper, Colorado potato beetle, cherry or grape
dipterous leafminers, granulate tomatoes (fruit less
cutworm, hornworms, southern than 1 inch in
armyworm, tomato fruitworm, diameter). Do not
tomato pinworm apply more than
1.2 Ib ai per acre
per season.
Provado 1.6F 12 0 foliar aphids, Colorado potato beetle, Do not apply to
(imidacloprid) leafhoppers, whiteflies crop that has been
treated with
imidacloprid or
thiamethoxam at
planting. Do not
apply more than
18.75 oz per acre
as foliar spray.
Pyrellin EC 12 12 hours aphids, Colorado potato beetle,
(pyrethrin + rotenone) cucumber beetles, flea beetles,
flea hoppers, leafhoppers,
leafminers, loopers, mites, plant
bugs, stink bugs, thrips,
vegetable weevil, whiteflies

Sevin 80S; XLR; 4F 12 3 Colorado potato beetle, **suppression
(carbaryl) cutworms, fall armyworm, flea Do not apply more
beetles, lace bugs, leafhoppers, than seven times.
plant bugs, stink bugs**,
thrips**, tomato fruitworm,
tomato hornworm, tomato
pinworm, sowbugs


Sevin 5 Bait 12 3 ants, crickets, cutworms,
(carbaryl) grasshoppers, mole crickets,
SpinTor 2SC 4 1 armyworms, Colorado potato Do not apply to
(spinosad) beetle, flower thrips, seedlings grown for
hornworms, Liriomyza transplant within a
leafminers, loopers, Thrips greenhouse or
palmi, tomato fruitworm, tomato shadehouse.
pinworm Leafminer and
thrips control may
be improved by
adding an adjuvant.
Do not apply more
than three times in
any 21 day period.
Do not apply more
than 29 oz. per
acre per crop.
Spod-X LC 4 0 beet armyworm Treat when larvae
(beet armyworm are young (1st and
nuclear polyhedrosis 2nd instar). Follow
virus) label instructions
for mixing. Use only
water at a pH near
7 for mixing.
Sulfur 24 see label tomato russet mite
*Telone C-35 5 days preplant garden centipedes See supplemental
(dichloropropene + (See (symphylans), wireworms label for restrictions
chloropicrin) label) in certain Florida
Trigard 12 0 Colorado potato beetle No more than 6
(cyromazine) (suppression of), leafminers applications per
Ultra Fine Oil 4 0 aphids, beetle larvae, Do not exceed four
(oil, insecticidal) leafhoppers, leafminers, mites, applications per
thrips, whiteflies season.
*Vydate L 2EC 48 3 aphids, Colorado potato beetle, Do not apply more
(oxamyl) leafminers (except Liriomyza than 32 pt. per acre
trifolii), whiteflies (suppression per season.
*Warrior 24 5 aphids 2), beet armywormo(, t> for control of 1st
(lambda-cyhalothrin) cabbage looper, Colorado and 2nd instars
potato beetle, cutworms, fall only.
armyworm(1), flea beetles, (2) suppression only
grasshoppers, hornworms, Do not apply more
leafhoppers, leafminers(2), plant than 0.36 Ib ai per
bugs, southern armyworm(), acre per season.
stink bugs, tomato fruitworm,
tomato pinworm, whiteflies(2)
"_.9 1yellowstriped armyworm(1)
hT, tiuI idUrL~ in fi ai a urrwt arladsaergltosa h ieo eiin h

e pes cJJ'~U e nrmaionI(II presented in this table was current with federal and staergltosa h ieo eiin h
Restritate regula
* Restricted Use Only -

Nematicides Registered for Use in Florida Tomatoes

J. W. Noling, UF, IFAS, Extension Nematology, CREC, Lake Alfred

Methyl Bromide3
67-33 225-375 lb 12" 3 112-187 lbs 5.1 8.61b
Chloropicrin' 300-500 lb 12" 3 150-250 lbs 6.9- 11.5 lb
Telone II2 9-12 gal 12" 3 4.5-9.0 gal 26 53 fl oz
Telone C-17 10.8-17.1 gal 12" 3 5.4-8.5 gal 31.8-50.2 fl oz
Telone C-35 13- 20.5 gal 12" 3 6.5-13 gal 22-45.4 fl oz
Metham Sodium 50-75 gal 5" 6 25 37.5 gal 56 111 fl oz
Vydate L treat soil before or at planting with any other appropriate nematicide or a Vydate transplant
water drench followed by Vydate foliar sprays at 7-14 day intervals through the season; do not apply
within 7 days of harvest; refer to directions in appropriate "state labels", which must be in the hand of
the user when applying pesticides under state registrations.

1 If treated area is tarped, dosage may be reduced by 33%.
2. The manufacturer of Telone II, Telone C-17, and Telone C-35 has restricted use only on soils that have
a relatively shallow hard pan or soil layer restrictive to downward water movement (such as a spodic
horizon) within six feet of the ground surface and are capable of supporting seepage irrigation regardless
of irrigation method employed. Higher label application rates are possible for fields with cyst-forming
nematodes. Consult manufacturers label for other use restrictions which might apply.
3 Use of methyl bromide for agricultural soil fumigation is scheduled for phaseout Jan 1, 2005.
4. Rate/acre estimated for row treatments to help determine the approximate amounts of chemical needed
per acre of field. If rows are closer, more chemical will be needed per acre; if wider, less.
Rates are believed to be correct for products listed when applied to mineral soils. Higher rates may be
required for muck (organic) soils. Growers have the final responsibility to guarantee that each product is
used in a manner consistent with the label. The information was compiled by the author as of July 25,
2003, as a reference for the commercial Florida tomato grower. The mentioning of a chemical or
proprietary product in this publication does not constitute a written recommendation or an endorsement
for its use by the University of Florida, Institute of Food and Agricultural Sciences, and does not imply its
approval to the exclusion of other products that may be suitable. Products mentioned in this publication
are subject to changing Environmental Protection Agency (EPA) rules, regulations, and restrictions.
Additional products may become available or approved for use.

University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs