The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
site maintained by the Florida
Cooperative Extension Service.
Copyright 2005, Board of Trustees, University
AREC SAN FORD o ARC- HASTINGS
INVESTIbATIONS LAB ORTORy
MARCH 2, 1972
AGRICULTURAL RESEARCH & EDUCATION
INSTITUTEE OF FOOD & AGRICULTURAL
- FIELD DAY REPORTS -
AGRICULTURAL RESEARCH AND EDUCATION CENTER- SANFORD
(Formerly Central Florida Experiment Station)
AGRICULTURAL RESEARCH CENTER- HASTINGS
(Formerly Potato Investigations Laboratory)
Thursday, March 2, 1972
Assembly and Registration 9:45 A. M.
Frank Jasa, Seminole County Extension Director, Presiding
10:00 A. M.
10:12 A. M.
10:24 A. M.
10:36 A. M.
11:05 A. M.
Welcome and Introduction J. F. Darby, Director,
Vegetable Crop Nutrition, Carrot Variety Trials and
Water Quality Studies R. B. Forbes, Associate
Soil Chemist, AREC- Sanford
Fertilization of Direct Seeded Cabbage on Sandy Soil -
D. R. Hensel, Director, ARC- Hastings
Nematode Control on Vegetables and Field Corn -
H, L. Rhoades, Associate Nematologist,
1971 Hybrid Field Corn Variety'Tests in Central, North,
and West Florida E. S. Horner, Agronomist,
Biology, Behavior and Management of Vegetable
Insects B. M. Shepard, Assistant Entomologist,
Control of Cabbage Insects-- Some Causes for Failure -
R. B. Workman, Associate Entomologist,
Coffee Break Courtesy of Geigy Chemical Co., and
Ferry-Morse Seed Co.
*Separate report "Agronomy Mimeo Report AG 72-1" available at
David DeVoll, Seminole County Extension Agent, Presiding
11:30 A. M.
11:42 A. M.
12:06 P. M.
12:30 P. M.
Research on Disease Control J. O. Strandberg,
Assistant Plant Pathologist, AREC- Sanford 19
Blackrot, Downy Mildew, and Damping-off of Cabbage
in the Hastings Area D. P. Weingartner, Assistant
Plant Pathologist, ARC- Hastings 27
Weed Control Trials on Cabbage at Hastings, Florida 1971 -
J. R. Schumaker, Assistant Horticulturist,
ARC- Hastings 30
Weed Control in Vegetables and Soybean Production -
W. T. Scudder, Horticulturist, AREC- Sanford 32
Catered Lunch-Corned Beef (or roast beef), cabbage,
green beans, salad, dessert, drink --- $1.50
1:30 3:00 P. M. Tour of Experimental Plots
John F. Darby
The Agricultural Research Center at Hastings and the Agricultural
Research and Education Center in Sanford have been having Field Days on
alternate years at their respective locations. This year, for the first time,
research results on experiments conducted on cabbage at Hastings are in-
cluded with the Sanford Field Day Reports. Next year the Field Day will
be held in Hastings and the research reports on experiments conducted on
cabbage in Sanford will be combined with the Hastings Field Day Reports.
Hybrid Field Corn Variety Tests in Central Florida.- Duplicate tests,
each consisting of 20 corn hybrids with normal (N) cytoplasm and two with
Texas male-sterile cytoplasm (T) were planted March 24-25, 1971 near
Sanford on mineral soil and near Zellwood on organic soil. The first lesion
of Helminthosporium maydis Race T was found July 8, 1971. Yields in
average bushels per acre of McCurdy 67-14 (N) and McCurdy 67-14 (T) were
112 and 107, respectively. In these tests the two highest yielding, good
quality, late maturing hybrids with N cytoplasm were Funk's G-4949 (113
bushels per acre) and Pioneer 3030 (106 bushels per acre). Funk's G-795W
(121 bushels per acre) and McCurdy 67-14 (112 bushels per acre) were the
two leading hybrids in the medium maturing group and Pioneer 3369 A (98
bushels per acre) and McNair X-210 (91 bushels per acre) in the early
These tests were carried out in cooperation with Dr. E. S. Horner,
Agronomy Department, Gainesville. Dr. Horner also had cooperative trials
at Quincy, Jay, Live Oak and Gainesville, using the same hybrids. He will
report on the results of all these tests. In addition, a separate report entitled,
"Hybrid Field Corn Variety Tests in Central, North and West Florida" is
available (Agronomy Mimeo Report AG 72-1).
Direct-Seeded Cabbage vs. Transplanted Cabbage.- The increased cost
of labor and its decreasing availability make it necessary to mechanize
cabbage production. Direct-seeding cabbage is an important part of the
mechanization program. For many years cabbage grown in this area has
been seeded in seedbeds and 40 to 50 days later pulled by hand and trans-
planted to the field.
Demonstration-type experiments showing the use of various pesticides
and fertilizer treatments on direct- seeded cabbage are available for inspection.
Most of the direct- seeded cabbage (Little Rock Variety) was seeded 3 inches
apart on November 11, 1971 with aJohn Deere Model 33, 2 row vegetable
planter. The plants were thinned to approximately one foot apart and the
resulting seedlings were transplanted in another area of the same field. Seed-
lings were also pulled from seedbeds and transplanted in the same field. We
hope to demonstrate that direct-seeded cabbage matures earlier with a higher
percentage of marketable heads for the first cutting.
VEGETABLE CROP NUTRITION, CARROT VARIETY TRIALS,
AND WATER QUALITY STUDIES
R. B. Forbes
Because of recent interest in seeding cabbage directly in the field,
rather than using transplants from a seedbed a series of experiments were
begun in September 1969 to work out a fertilization program for direct-
To date 6 trial plantings have been made. The most recent, seeded in
November 1971 is outlined below.
Cabbage variety: Little Rock
Planting date: 11-15-71
Harvest of seeding plants: 1-19-72
Fertilization of Direct-Seeded Cabbage
Average of 5 replicates
Height Growth1 Weight of
Treatment inches rating plants, lb
1. Check, no fertilizer 5.7 0 1.2
2. 500 lb/A 5-5-8-2 pre-plant broadcast 7.4 2.3 2.6
+ 500 lb/A @ 4 weeks
3. 1000 lb/A 5-5-8-2 pre-plant broadcast 8.2 3.2 3.9
+ 500 lb/A @ 4 weeks
4. 500 lb/A 10-4-10-3 pre-plant broadcast 9.1 3.6 5.0
+ 500 lb/A @ 4 weeks
5. No pre-plant fertilizer, sidedress 10.3 4.0 5.1
with (417 lb/A 6-2-8 liquid @ 2 weeks
and 4 weeks
6. 500 lb/A 5-5-8-2 pre-plant broadcast 10.7 4.4 6.9
+(417 lb/A)6-2-8 liquid @ 2 weeks and
7. 500 lb/A 5-5-8-2 pre-plant broadcast 6.8 2.2 2.5
+ Soil-life + 500 lb/A 5-5-9-2 @ 4 weeks
8. 500 lb /A 5-5-8-2 pre-plant broadcast 7.0 2.2 2.3
+ Aqua Humus + 500 lb/A 5-5-8-2
@ 4 weeks
9. No pre-plant fertilizer, sidedress @ 9.5 3.6 4.5
2 weeks and 4 weeks with 500 lb,/A
10. No pre-plant fertilizer, sidedress @ 10.7 4.5 6.4
2 and 4 weeks with 500 lb/A 10-4-10-3
11. 1000 lb/A 5-5-8-2 pre-plant broadcast 9.0 3.7 5.4
+ 20-20-20 drench 3-/ 4 applications
- 0-5 rating scale, 0=unfertilized checks, 5=best plants, rated on basis of
size, vigor, color, general appearance.
- Weight of 24 plants from each plot.
- 5 lbs/100 gal, 4 applications, each at rate of 300 gpa.
In summary, results of this trial show that good seedling growth can
be obtained by a pre-plant application of solid fertilizer plus side dressings
of either solid or liquid fertilizer. The liquid fertilizer has given a very
quick response. No benefit was obtained from the two soil conditioners.
Better success-has been obtained with September, October or early
November plantings than with cabbage direct-seeded in December, January
Carrot Variety Trials.- The following table gives the varieties and
advanced breeding lines that are being tested in replicated trials. Planting
date for the Sanford trials was October 14, 1971 and October 21 for the
Zellwood planting, with six replicates at each location.
Fresh Market Lines
Long Imperator II
Gold Pak 12120
Imperator, Long type
Impr. Nantes Early
Tito, Nantes Med.
Waltham Hicolor 32 8
Gold Pak 28
- Blight ratings from Ullstrupfs Scale: 0=no blight; 5=very heavy
lesions abundant on all leaves.
No fungicides were applied until late January, after blight conditions
had become severe. Ratings were made on January 17, 1972 at Sanford
and on February 8 at Zellwood. Yield data are not yet available.
1 Red Core Chantenay 503
2 Red Core Danvers
3 Danvers Pride
4 Kinko Chantenay 6
5 Kinko Chantenay 8
Planting dates: Sanford, October 14, 1971
Zellwood, December 22, 1971
Observational plantings.- In addition to the replicated plantings listed, single
plots of several numbered lines were planted for observation. These are
listed as follows:
Observational Lines, Sanford
Plot No. Designation Source Blight Rating
0-1 D 301A x M 6000C Dessert 3.6
0-2 M5931A x D301B 3.2
0-3 D301A 3.6
0-4 Hipak Elite 310 E J. Harris 3.8
0-5 NCX 6000 Niagara 3.5
0-6 NCX 6001 3.5
0-7 NCX 6002 2.5
Planting date: October 14, 1971
Observational Lines, Zellwood
D 301A x M6000C
M5931A x D 301B
Hipak Elite 310E
Special Long Type Nantes
Forcing, Bak strain
Scarlet Nantes, Strong Top
Scarlet Nantes, Coreless
December 22, 1971
Several hundred USDA plant introductions and advanced breeding lines
were grown at Zellwood in a cooperative effort with Dr. Strandberg of this
Center, Dr. Bassett of the Vegetable Crops Department at the main Station,
and Dr. C. E. Peterson, USDA. Many selections were made for further
breeding toward a high quality carrot with disease (Alternaria) resistance
for Florida conditions.
Water Quality Studies.- Sampling of water from canals in the Zellwood
farming area and from Lake Apopka has been continued on a regular basis,
and since 1970 samples have been taken from the waterways downstream
from the lake.
Phosphorus levels in the drainage canals were generally higher than in
the lake, with higher levels in the canals during periods of excess rainfall.
Total solids and soluble salts were higher in canals than in the lake at most
sampling periods, but the canal water was generally lower in turbidity than
the lake. No pesticides have been found since May 1968 except for a trace
(less than 0. 001 ppm) of DDT reported in November 1969.
In a cooperative study with Dr. Hortenstine of the Soil Science Department,
soil water samples were extracted from Everglades mucky peat in the Zellwood
area under different conditions: swampy, uncleared land, newly cleared land
and land that had been cultivated for 15 years. Nutrient concentrations in
water extracted from 2 feet below the surface in the newly cleared area in-
creased by as much as 8 to 12 times over the uncleared, swampland. Further
increases were noted in the cultivated land.
Results from a fertilizer rate study showed that even with no fertilizer
added, significant amounts of nutrients were present in the soil water. Normal
rates of fertilization contributed only a little to the nutrient level in the water,
but doubling the fertilizer rate produced a noticeable increase. Collection
tubes were installed at depths up to 48 inches, in some instances reaching
the marl layer underneath the peat. Water samples taken from this layer
were very much reduced in phosphorus content compared to those from the
organic soil itself at the 2 foot depth.
FERTILIZATION OF DIRECT-SEEDED CABBAGE ON SANDY SOIL
D. R. Hensel
Direct- seeding of cabbage in Florida is not new, however, very little of
it has been done on sandy soil. With the advent of mechanical harvesting,
researchers in Florida have shown that greater uniformity of stands, growth,
and maturity as well as earlier maturity can be obtained by direct-seeding as
compared to transplanted cabbage. Little or no research has been done to
establish the optimum level and method of fertilizing direct- seeded cabbage.
In comparing salts and moisture stresses to the two methods of planting, the
transplanted cabbage will tolerate greater fluctuations than direct-seeded.
During the winter growing seasons of 1969-70 and 1970-71, three ferti-
lization rates of broadcasting and banding were combined with three rates
of sidedressing on direct-seeded cabbage.
Weather conditions were quite different. In 1969-70, the growing season
was wet, and the fertilizer applications were subjected to much leaching.
Whereas in 1970-71, the opposite was true. Very little rain fell during the
time the plants were in the small seedling state which resulted in poor
stands and loss of vigor. Analysis of salt concentrations by the I & B Method
in the 0-6 level showed very high amounts of salt accumulated in all treat-
ments, however, significant increases were due to high applications of both
broadcast and banded fertilizer.
The following table shows differences in the yields between fertilizer rates
which are significant for both seasons, however, the trends are reversed.
Additional sidedressing increased yields in 1969-70 only at lower rates of
application of the banded and broadcast methods, whereas they had no effect
Table 1.- Total yield of direct-seeded cabbage.
Treatment 6-8-8 1969-70 1970-71
#/A T/A T/A
Broadcast 400 8.2 10.7
1000 10..5 9.2
1600 12.2 7.6
Banded 600 8.4 10.0
1500 10.4 9.3
2400 12.2 8.4
NEMATODE CONTROL ON VEGETABLES AND FIELD CORN
H. L. Rhoades
Nematicide Screening.- Of several experimental nematicides tested
during the past year, two have given effective control of root-knot and sting
nematodes and will be investigated further. They are: American Cyanamid
Company's AC-64475 and Ciba-Geigy's CGA-10476.
Cabbage.- The sugarbeet nematode, Heterodera schachtii, is a cyst
nematode that is also a pest of crucifers. This nematode was discovered
in a commercial field of cabbage in the Sanford area in 1969, after which
populations were reared in the greenhouse for experimental purposes. The
results of a pathogenicity test conducted in the greenhouse and a soil fumi-
gation test conducted in the infested field during 1971 are presented in
Tables 1 and 2 respectively.
Table 1.-Effect of Heterodera schachtii on the growth of cabbage
Plant Weight Nematode
Treatment First Planting Second Planting Third Planting Population
Check 346 545 247 ---
100 cysts 291 375 64 19300
1000 cysts 276 354 69 22800
LSD 05 N. S. 108 70
.01 152 100
aAverage weight of plants in grams of fresh weight.
Number of larvae extracted from 100 cc of soil after the second harvest.
Table 2.-Effect of D-D and DBCP on populations of the sugar beet, sting and
Nematode Populations a
Treatment Sting Lance Sugar beet (larvae)
Check 41 213 238
D-D, 25 gal/acre 0 12 32
DBCP, 25 lb/acre 0 10 30
a Average number of nematodes extracted from 100 cc of soil.
Average number of nematodes extracted from 100 cc of soil.
- 10 -
The results of an experiment in which promising experimental nemati-
cides were applied for the control of sting nematodes on cabbage are pre-
sented in Table 3. All treatments reduced nematode populations and increas-
ed yields significantly. There seemed to be little difference in efficacy of
the chemicals when applied as granules or as liquid in transplant water.
Table 3.-Effect of nematicides on sting nematodes and yield of cabbage.
Treatment Rate/Acre Method of application nematodes (lb. /plot)
Check --- 85 28
Furadan 2 lb. in-row Grans. incorporated 35 50
t" Liquid in transplant water 61 51
Dasanit Granules 24 56
Transplant water 26 57
Nemacur Granules 8 61
Transplant water 23 48
Mocap Granules 25 42
Transplant water 47 46
D-1410 Granules 67 53
Transplant water 25 55
AC-64475 Granules 21 54
Dyfonate Granules 24 45
LSD .05 10
aNumber of nematodes extracted from 100 cc of soil at harvest time.
Snapbeans.- The results of an experiment in which experimental
nematicides were applied prior to planting Harvester snap beans are
presented in Table 4. This experiment was conducted in an area heavily
infested with sting nematodes. All treatments reduced nematode populations
and gave an excellent increase in yield.
- 11 -
Table 4.- Effect of nematicides on sting nematodes and yield of snap beans.
Rate/acre Sting Yield
Treatment (in-row) nematodes (bulacre)
a Number of nematodes extracted from 100 cc of soil.
Number of nematodes extracted from 100 cc of soil.
- 12 -
Cucumbers.- Nemagon (DBCP) and experimental nematicides were
applied on cucumbers in an area infested with sting and root-knot nematodes
in the spring of 1971. Results are shown in Table 5.
Table 5.-Effect of nematicides on sting and root-knot nematodes and yield
Sting Root-kot d
Treatment Rate/acre nematodes index Yield
Check --- 66 --c 2
DBCP 1/2 gal 2 1.35 108
Tirpate 1 lb 8 1.46 113
2" 17 1.15 111
Nemacur 1 29 3.08 85
2" 29 2.06 108
Furadan 1 32 3.15 88
2" 23 3.49 82
Mocap 1 31 1.81 83
2" 23 2.05 77
D-1410 1" granss.) 12 3.28 92
S2 ( ) 17 2.23 109
1 (foliar spray) 45 c 4
2 ( ) 25 --c 16
2 (1 lb grans+1 lb foliar
spray) 5 2.50 118
2 (2 granss+ 2 lb foliar
spray) 1 2.05 115
aNumber of nematodes extracted from 100 cc of soil.
bBased on a root galling index of 1, no galling, to 5, severe galling.
Not enough plants were present at harvest time to index for root-knot galling.
d Pounds per plot 40 feet of one row).
Pounds per plot (40 feet of one row).
- 13 -
Carrots.- The results of a nematicide experiment on carrots is presented
in Table 6. Yield was improved and the % culls was reduced by all treatments.
Table 6.- Effect of nematicides on sting and root-knot nematodes and yield
Treatment Rate/acre nematodes Yield % Culls
Check --- 85 16 43
Temik 5 Ib 23 31 5
Furadan 5 21 26 8
Mocap 5 13 22 15
Nemacur 5 0 26 8
Dasanit 5 31 26 6
Tirpate] 5 6 24 5
D-1410 5 63 27 23
LSD .05 12
aAverage number of nematodes extracted from 100 cc of soil.
bPounds of carrots obtained from 15 feet of plot row.
Field Corn.- Several fields used for winter vegetable production also
produce field corn during the spring and summer months. If plant nematodes
are not controlled, the corn can be injured severely. In 1971 an experiment
was conducted in an area heavily infested with sting nematodes. The results
of this experiment are presented in Table 7.
- 14 -
Table 7.- Effect of nematicides on
sting nematode populations and yield of
Treatment Rate/acre Sting nematodes a Yield (bu/acre)
Check 295 14
Dyfonate 2 lb 176 70
4 102 87
Nemacur 1 95 85
2" 14 99
Thimet 2 55 94
Mocap 1" 112 83
2" 92 101
D-1410 1 196 81
2" 95 103
Furadan 1 115 94
2" 102 104
aNumber of nematodes extracted from 100 cc of soil at harvest time.
Effect of temperature on nematode activity.- An experiment was conducted
in environators to determine the temperature at which sting and sugarbeet
nematodes are most active. Reproduction was highest at 25 C (77 F) for sting
nematodes and 20 C (68 F) for the sugarbeet nematode. Results are presented
in Table 8.
Table 8.- Effect of temperature on reproduction of sting and sugarbeet
Nematode populations a
Nematode Crop 15 C (59F) 20 C (68 F) 25 C (77 F) 30 C (86 F)
Sting Rye 208 800 12,336 2,672
Sorghum 224 1,872 16,592 5,808
Suarbeetb Cabbage 4, 224 8,208 5,776 2,496
Sugarbeet 5,552 12,880 3,776 1,824
Total number of nematodes that had accumulated in 6-inch pots in 3 months.
Pots containing sting nematodes were originally infested with 100 specimens.
Those containing sugarbeet nematodes were originally infested with 500 cysts.
bSecond stage larvae.
Signalgrass as a host for nematodes.- Narrowleaf signalgrass, Brachiaria
piligera, is a common weed grass in central Florida and grows abundantly in
the winter vegetable fields during the off season summer months. What appear-
ed to be sting and stubby-root nematode injury symptoms were observed on
the roots and, upon examination, high populations of both were found in the
root zone. Subsequent greenhouse experiments revealed that this plant is an
excellent host for sting, stubby-root and lance nematoces, a moderately good
host for awl nematodes, but a non-host of root-knot and the lesion nematode,
- 16 -
BIOLOGY, BEHAVIOR AND MANAGEMENT OF VEGETABLE INSECTS
B. M. Shepard
Bean Leaf Roller:
Field populations.- Counts of bean leaf roller eggs and larvae were
taken from bean fields of several sizes to help to develop better sampling
methods. Fitting 13 sets of data to a computer program showed that the
bean leaf roller was not distributed randomly in the field, but existed in
"clumps" or certain pockets of heavier or lighter concentrations. This
information on field populations will provide helpful information about how
to sample for the bean leaf roller and perform the correct analysis of data
from treatment plots.
Effect of crowding.- Pupation and pupal weights of the bean leaf roller
as effected by crowding was noted in replicated laboratory tests. A summary
of the results is given in Table 1. Although food was not a limiting factor,
from 5 20 larvae per container significantly reduced pupal weight when
compared to one larva per container and from 21 to 40. 5 per cent mortality
occurred in containers with 10 and 20 larvae respectively. Thus, com-
petition for space may be a natural regulating mechanism with the bean leaf
roller at high population levels in the field.
Table 1.- Pupation and pupal weight of the bean leaf roller as influenced by
No. larvae/container No. Reps. Mean pupal wt. (mg.) Per cent pupation
1 20 .5157 a 95
5 10 .4009 b 92
10 10 .4117 b 79
20 10 .3973 b 59.5
Granular materials for control of wireworms on carrots:
Nine granular materials were broadcast on November 17, 1971 in
replicated trials two weeks prior to planting carrots on the Zellwood muck.
Using a randomized complete block design these materials and the rates
used are listed in Table 2. Wireworm control will be assessed at the end
of the test period.
- 17 -
Table 2.- Granular materials applied for control of wireworms on carrots.
Material Manufacturer Rate (lb/acre)
Dyfonate 10-G Stauffer 4
N-2596 20-G Stauffer 4
Furadan 10-G Niagara 4
Dasanit 15-G Chemagro 4
Mocap 10-G Mobil 6
Thimet 10-G American Cyanamid 4
Parathion 10-G Asgrow 5
Diazinon 14-G Geigy 4
Primicid 10-G ICI 4
Incidence of parasitism of the cabbage looper:
Random collections of all instars of cabbage looper were made from
October 1971 through January 1972. Of a total of 907 looper larvae collected,
returned to the laboratory and reared on artificial diet, only about 4 per cent
were parasitized. The most abundant parasite was a polyembronic species,
Copidosoma troncatellum, which made up 84 per cent of the total parasites
collected. An unidentified braconid was next in abundance. Further experi-
ments are planned to monitor the naturally occurring parasites of pest insects
Current or proposed research:
1. Evaluation of materials for control of insect pests on ornamentals.
(Tests using granular materials for control of Rhizoecus americanus are in
2. Cabbage pest management.
3. Soil temperature preference sampling and distribution of wireworms.
4. Evaluation of an introduced predator for cabbage insect control.
5. Foraging and circadion behavior of vegetable insects.
6. Insecticide screening tests on celery, cabbage and sweet corn.
7. Biology and predatory activity of the striped earwig, Labidura riparia.
- 18 -
CONTROL OF CABBAGE INSECTS--SOME CAUSES FOR FAILURE
R. B. Workman
Waited too long.- Insects are more difficult to control when large or
mature. Large insect populations are more difficult to control than small
ones. Insecticide coverage on large plants is more difficult than on small
Used wrong insecticide.- Insect may have developed resistance to the
insecticide. Ineffective insecticide may have been used because of lower cost.
Ineffective insecticide may have been used because of poor recommendation.
The insecticide. may not control a particular insect. Know your insects.
Poor coverage.- For best control, insecticides must contact all leaf
surfaces where insects feed or hide. Growers experiencing control problems
should examine plants just after treatment to see which portions of the plant
are not covered. Nozzle adjustment can be made until complete coverage is
obtained. Some suggestions include:
1. Use 6 nozzles per row with output of about 100 gal/A and 200-300
psi to cover tops, sides, and under parts of plants.
2. Nozzles should be close enough to the plants so that there is sufficient
pressure to cover the inner portions. A lot of fog behind the sprayer
does not mean good coverage.
3. Hollow or solid-cone nozzles give better coverage than flat-spray types.
4. Spreader-stickers improve penetration and sticking, but too much will
cause the pesticide to run off the plant onto the ground where it is lost.
5. Check boom for plugged nozzles regularly. One plugged nozzle (of 6 per
row) results in about 17% less spray on that row.
Follow instructions on the insecticide label at all times.-
Directions for use.
Safety and First Aid directions.
- 19 -
RESEARCH ON DISEASE CONTROL
J. O. Strandberg
Cabbage Black Speck and Variety Trials, 1971-72.- The cabbage variety
trials available for inspection are part of a continuing program of variety
testing which was begun in 1965. This season 93 commercial and experi-
mental hybrid varieties are being evaluated in replicated trials for black
speck and other disease resistance as well as horticultural characteristics
of interest to Florida growers.
These tests are carried out under the same seedbed and field conditions
encountered by Florida growers. However, black speck ratings are made
under severe storage conditions previously shown to be optimum for symptom
development (4 C for 14 days). Plot areas were tested for plant parasitic
nematodes, but since potentially damaging populations were not present the
plots were not fumigated. Insects were controlled with weekly applications
of Lannate at 1/2 lb/acre. Plants are placed 10 inches in 30 inch rows.
Plant beds were seeded October 15 and transplanting took place on November 23.
Observational Variety Trials.- An observational trial consisting of
cabbage, red cabbage, cauliflower, broccoli and brussel sprouts is also
available for inspection. These trials are for the purpose of preliminary
observation and are not replicated. The observational trials were main-
tained using the same methods employed on the variety trials except that
plot areas were fumigated for nematodes two weeks before planting with
20 gal/acre of a dichloipropane-dichloropropene mixture.
Results of these trials will be available in mimeographed form in
Research on Pythium Brown Root of Carrot.- A serious problem of
carrots grown on organic soils has recently been traced to damage caused
by a fungus (Pythium sp. ). The name Pythium Brown Root has been given
to this disease problem. In Florida, Pythium brown root has not been
observed on mineral soils, but is present wherever carrots are grown on
organic soils. There are several types of damage caused by this disease
ranging from a severe damping-off phase to a browning of tap and lateral
roots. When the tap root is attacked at an early stage, root development
ceases below the point of injury resulting in a stubby carrot. Proliferation
of lateral roots just above the point of attack results in forked roots.
The Pythium brown root fungus was found to attack several species in
the Umbelliferae including carrot, wild carrot, celery and wild celery
(Apium leptophyllum) where it produced severe root damage and stunted tops.
Continuous carrot-carrot and carrot-celery rotations have resulted in
severely infested areas which are no longer economical for carrot production.
Other crops routinely grown on Florida organic soils such as sweet corn and
leaf crops are not affected by the brown root fungus.
- 20 -
A greenhouse soil assay method which involves growing carrots in
samples of field collected soil has been developed. Population estimates
using a soil plate- selective medium technique have generally, but not
always, confirmed field observation and greenhouse test results. Pre-
liminary results indicate that land previously planted with celery produced
the highest level of pythium damage to carrots.
Alternaria Leaf Blight in Carrots.- Alternaria daucii is probably the
most important organism affecting carrots in many production areas.
Alternaria blight causes severe yield losses and harvesting difficulties
because of loss of carrot tops and the cost of numerous fungicide applications
further reduces dollar returns. The absence of leaf blight resistance in all
recently developed carrot varieties has precluded their use in Florida and
other production areas. Therefore, recent advances in carrot breeding
cannot be utilized without the development of some form of inexpensive
disease control. In Florida, our search for better control measures has
been directed toward: 1) Searching for disease resistance, and 2) improved
timing and elimination of unnecessary fungicide applications by gaining more
knowledge of the etiology of the disease.
Examination of many commercial carrot breeding lines and the entire
Plant Introduction carrot collection in both greenhouse and field experiments
showed that immunity to A. daucii does not exist in any carrot or wild
Daucus species. There are, however, various levels of tolerance, some
of which could be very useful in a carrot breeding program. Several lines
previously reported Alternaria resistant were found to be completely
susceptible demonstrating the past confusion of Alternaria blight with other
foliar diseases of carrot such as Cercospora carotae and Xanthomonas carotae.
At present, several fungicides are used to control Alternaria blight. Our
tests in Florida have shown Bravo, maneb-zinc complexes and maneb fungi-
cides to be superior to other fungicides in this application.
The possibility of disease forecasting to better time fungicide applications
and eliminate unnecessary ones was examined. The results indicated that
such a program would probably not be feasible due to the rather broad set
of environmental conditions under which A. daucii is active. Spore trapping
and field observations supported by laboratory and greenhouse experiments
demonstrated that A. daucii spores are produced overnight on infected
foliage and are dispensed by winds as low as 5-10 mph when humidity drops
during late morning or early afternoon. Actual spore release and dispersal
were clearly shown to be related to wind and relative humidity, whereas,
spore production except in the most general way was not correlated with
measured weather parameters.
Further laboratory and greenhouse work demonstrated that A. daucii
while rather typical in growth temperature requirements grew over a very
wide pH range and sporulated over a temperature range of 12-28 C. Conidia
germinated between 4-28 C on leaves in the presence of free water. Spor-
ulation or germination did not occur at relative humidities less than 100%.
It was concluded that the key factor in the life cycle of A. daucii aside from
otherwise favorable conditions of temperature was free of moisture in the
form of dew. Dew production is hardly an uncommon event in Florida, but
it cannot be predicted with normal weather monitoring equipment. At
present, a dew recorder has been constructed and we are in the process
of trying to correlate this season's spore counts with dew recorder data.
- 22 -
Cabbage Black Speck and Variety Trials
Transplanted November 23, 1971
Variety or Line
Ex Hyb 6039
Ex Hyb 6425
Ex Hyb 6040
Ex Hyb 5926
Ex Hyb 6036
Ex Hyb 6037
Ex Hyb 6038
Ex Hyb 6526
11C X 23
11C x 11
- 23 -
Variety or Line
Tokyo Pride #21
Green Express #72
Ex Hyb 31
Ex Hyb M-3010
Ex Hyb 0
Ex Hyb P
Ex Hyb B
Ex Hyb U
Trial No. Variety or Line Lot No. Source Remarks
89 Ruby Ball Takii
90 C-M Cross "
91 C-G Cross "
92 Perfection Cross "
93 Velocity Cross / "
- 25 -
Transplanted November 24, 1971
Line or Variety
Ex Hyb 7
Ex Hyb 6
Ex Hyb 2
Hyb Broccoli Green Duke
Ex Hyb 3129
Ex Hyb 9542
Ex Hyb 9580
Ex Hyb 9581
Cauliflower Snowball A
Cauliflower Snowball X
Cauliflower Snowball Y
Hyb Broccoli Crusader
Hyb Broccoli Bravo
Hyb Broccoli C
Hyb Broccoli B
Brussel Sprouts Parcifal
Broccoli Watham 29
Broccoli Ex Hyb a
Brussel Sprout Peer Gynt
Hyb Cabbage Synargreen
Broccoli MSU 109
Broccoli MSU 108
Cauliflower MSU 512
Cauliflower Snowball Imperial
Cauliflower Snowball Y
Sluis & Groot
Sluis & Groot
Line or Variety
Cauliflower Snowball Imperial 339-10-563
Cauliflower Snowball Imperial 339-10/300
Cauliflower Snowball Imperial 339-10/400
Cauliflower Snowball Imperial 339/100
Cauliflower Snowball Imperial 339/200
Hybrid Broccoli Premium Crop
Hybrid Broccoli Southern Comet
Hybrid Broccoli Cape Queen
- 27 -
BLACKROT, DOWNY MILDEW, AND DAMPING-OFF
OF CABBAGE IN THE HASTINGS AREA
D. P. Weingartner
Blackrot of Cabbage.- As in other areas of the state, blackrot of
crucifers has been severe in the Hastings area during the past 3 seasons.
This disease is currently the most important disease of cabbage in Florida.
Studies of blackrot in the Hastings area have been limited to field observations
and small spray trials in which various antibiotics have been evaluated for
curative effects. To date, none of the antibiotics tested have been effective
under the test conditions. Observations of the disease in the field have
suggested the following:
1. Differences in varietal response to the disease vary widely.
In the Hastings area, Market Prize (90% acreage) is much
more severely affected than Abbott and Cobb No. 5.
2. Disease in the field can usually be traced to a particular
lot of transplants.
3. Sound sanitation practices, particularly during periods of
infrequent rains, have helped to reduce spread of the
disease in the field.
4. Freezing temperatures drastically reduce spread of the
disease, even when subsequent temperatures and
precipitation favor rapid dissemination of blackrot
5. Healthy plants have been grown on some fields within
10-14 months of heavy infestations of blackrot.
6. Crucifer weeds which could serve as reservoirs of bacteria
have not been found adjacent to heavily infested seedbeds.
7. Fields of Market Prize showing 10-15% primary infection
or transplant infection within 2-3 weeks after transplanting
usually will not produce a profitable yield.
In areas where blackrot is a problem, the following suggestions are
1. Use only hot water treated seed or transplants grown from hot
water treated seed on new land or land planted to noncrucifers
for 2 years.
- 28 -
2. Plant less susceptible varieties. Even alternating beds of
susceptible and nonsusceptible varieties will help reduce
rate and extent of spread.
3. Follow sound sanitary procedures if blackrot is observed.
(See POL Mimeo 71-3).
Downy Mildew and Damping-off.- Downy mildew and damping-off are
the most serious diseases affecting cabbage seedlings. Downy mildew is
caused by a fungus or mold called Peronospora parasitica. When the fungus
infects cotyledons of small seedlings, severe retardation of growth and even
seedling death can result. Damping-off can be caused by several fungi in
Hastings area seedbeds, however, Rhizoctonia and occasionally Pythium
have been the most important problems.
Results of Tests to Control Downy Mildew in Cabbage Seedbeds.- In
1969, experiments were initiated with various formulations of maneb, maneb-
related fungicides and several new fungicides which had not been extensively
tested in the Hastings area. Rates of the organic fungicides were doubled
over those previously recommended for use. Results of the 1969-70 test
were reported in POL Mimeo Report 71-1 Revised. Generally, all of the
organic fungicides tested gave excellent control of downy mildew at the
In 1970-71 fungicides which looked promising the previous year were
applied at 3 different rates and were compared to the recommended rate
of chloranil (4.0 lb. 65W/acre). The higher rates were again more effective.
(POL Mimeo 71-10). The test further indicated that adherence of fungicides
to foliage was a very important factor limiting adequate control.
This year 3 rates of maneb and 4 different adjuvants are being tested.
The data are at this time incomplete. The higher rate (3.0 lb/acre),
however, seems to be more effectively controlling downy mildew. No
striking differences have been observed among the adjuvant treatments.
Several observations made during these 3 experiments are important to
1. Thorough coverage including the under surfaces of cotyledons
2. Adequate protection of seedlings during the first 10 days after
emergence can dramatically increase seedling vigor and growth.
3. Until more is learned concerning use of adjuvants, sprays
should be applied after rains and as often as needed to protect
- 29 -
Damping-off Experiment.- This year, twelve soil fungicides were
applied to cabbage seedbeds in an attempt to reduce damping-off and
wirestem caused by Rhizoctonia. Fungicides were applied to the seedbeds
with a low pressure weed sprayer and were then watered into the soil by
drenching the beds with approximately 700 gallons of water per acre. No
significant differences were observed in the number of surviving seedlings.
Wirestem was, however, significantly reduced by several materials.
Table 1.- Results of 1972 experiment to control damping-off and wirestem
in cabbage seedbeds.
Treatment- % Wirestem-
Demosan 65W (5.0) + Terraclor 75W (30.0) 9.1*
Demosan 65W (3.75) 15.9
Terraclor 75W (30.0) 16.2
Benlate 50W (4.0) 11.9*
Bravo 75W (6.0) 12.0*
Bravo 75W (12.0) 11.8*
- All rates are pounds formulation broadcast per acre.
rate by 1/3 to obtain rate applied in 12-14 inch bands
over seed drills.
2/Asterisk indicates differences significant from control at 5%.
Although statistically significant, the observed reductions in wirestem
probably would not justify the cost of the materials. The effect of the
Terraclor and Demosan treatments appeared to be additive. The low rate
of Bravo was equally as effective as the high rate. Subsequent tests will
emphasize timing of application, multiple applications and rates. Bravo
and Terraclor are the only materials listed which are currently registered
for use on cabbage.
- 30 -
WEED CONTROL TRIALS ON CABBAGE AT HASTINGS, FLORIDA 1971
J. R. Shumaker
Methods.- Cultivar, Head Start, transplanted 11/30/70. Treatments were
broadcast over the tops of cabbage via 4-row sprayer--40 gpa; 30 psi--with 3
flat-tip nozzles per row on 12/21/70. Cabbage harvest and weed ratings were
taken oh March 1 and 3, 1971, respectively.
Results.- Chemical injury to the crop was not observed in these trials.
Weed pressures, while not great until late season, were virtually entirely
due to broadleaf species. Predominate weeds were the seedling docks
(Rumex spp. ), chickweed (Stellaria media), and primrose (Oenothera lacniata).
Of minor importance were cudweed (Gnaphalium peregrinum) and the water-
cresses, (Rorippa spp.). The most numerous and troublesome weed was dock
which constituted approximately 50% of the total weed pressures, while chick-
weed and primrose (and other weeds) each constituted 25%. Significantly
greater weed control was observed in all chemically treated plots than was
observed in the control (Table 1). Lasso at 3. 0 ai/A (lb. ), Planavin at 1. 0
and 0. 5 ai/A (lb.), Lasso + Vegadex at 1. 5 + 3. 0 ai/A (lb.), Dacthal + Lasso
at 6.0 + 1.5 ai/A (lb.), and Dacthal + Tok at 6. 0 + 4.0 ai/A (lb.) were
effective in controlling dock, chickweed, and primrose. Both the 10. 5 and
6. 0 ai/A (lb.) rates of Dacthal were very effective in controlling dock and
chickweed, but they were slightly less effective in controlling primrose.
Lasso at 1. 5 ai/A (lb.) controlled dock and primrose effectively but was
less effective in controlling chickweed. Tok at 4. 0 ai/A (lb. ) was effective
in controlling dock and primrose but was not effective in controlling chickweed.
Randox + Vegadex at 3. 0 + 3. 9 ai/A (lb.) and Vegadex at 6. 0 ai/A (lb.) were
effective in controlling chickweed and primrose, but were not effective in
controlling dock. Yield differences between treatments were not significant;
however, all chemical treatments did produce greater yields than the control.
Recommendations.- Dacthal, Vegadex, Randox, and a combination of
Vegadex and Randox are approved for use on cabbage under local conditions.
They are recommended and have been used quite extensively by local growers.
Planavin and Tok are also approved for use on cabbage but have not been
thoroughly tested under local conditions and, therefore, can only be suggested
for trial purposes. At this date, Lasso is not approved for use on cabbage.
Growers are urged to proceed with caution when applying herbicides. Always
read the container label and check for recent changes regarding crop, rate,
time schedule, soil type, and method of application approved for use. Serious
problems may result if label is not followed closely.
- 31 -
Table 1.- Ratings and yields of 1970-71
weed control trials on cabbage at
Weed Control Ratings--
Broadcast Primrose -
rate and other Yield
Herbicide R lb. ai/A- Dock Chickweed weeds CWT/A
Lasso 4E 3.0 9.4 8.5 9.5 173
Dacthal 75W 6.0 9.4 8.9 7.5 190
Dacthal 75W 10.5 9.3 8.9 7.8 195
Lasso 4E +
Vegadex 4E- 1.5 + 3.0 9.3 8.5 9.3 187
Lasso 4E- 6.0+ 1.5 9.3 9.0 8.6 178
Lasso 4E 1.5 8.6 6.9 9.3 199
Dacthal 75W +
Tok 50W 5/ 6.0+4.0 8.6 8.1 8.9 177
Tok 50W 4.0 8.5 3.3 8.4 193
Planavin 4E 1.0 8.4 8.9 8.1 197
Planavin 4E 0.5 7.5 7.4 8.3 176
Vegadex 4E 6.0 5.5 9.0 9.8 168
Randox 4E +
Vegadex 4E- 3.0+ 3.0 4.5 8.5 9.1 170
Control -- 1.0 1.0 1.0 167
LSD .05 1.82 1.70 1.37 N. S.
1/of active ingredient per acre.
- Pounds of active ingredient per acre.
- Scale 1-10; 1 no control, 10 complete
control, 7 acceptable.
- Primrose 95% of this group, others include cudweed, watercress and
- Tank mix.
- Separate applications.
- 32 -
WEED CONTROL IN VEGETABLES AND
W. T. Scudder
Weed Control in Vegetable Crops.- Besides preliminary screening trials to
test the performance of new chemical herbicides on 40 different crop species,
replicated trials have been conducted with several crops to evaluate the most
promising new herbicide treatments in comparison with those currently registered.
The following tables summarize the information from several experiments with
cabbage, cucumbers, onions, and snap beans. Herbicide rates are given in
terms of pounds per acre of active ingredient.
Table 1.- Cabbage Weed Control.
Treatment a Crop Weed Control
Herbicide Rate Timing Tolerance Bl Gr
Trifluralin 3/4* PPI 10 5 10
Nitralin 1* 10 5 8
Bensulide 6 10 5 9
CDEC 6* Pre E 10 9 5
CDEC + CDAA 3 + 3* 10 9 6
CDEC + Propachlor 2-1/2 + 2-1/2 9 10 6
Propachlor 5 8 9 8
Alachlor 2 10 8 8
Diphenamid 5 10 7 7
DCPA 10-1/2* 10 6 9
BAS-2903 4 9 10 9
Fluorodifen 3 7 8 7
Nitrofen 3* Post E 10 6 7
Check -- --- 10 0 0
Notes: *Treatments registered for grower use.
PPI = Pre-plant incorporated
Pre E = Pre-emergence to crop and weeds
Post E = Early post-emergence to crop and weeds
Crop Tolerance Ratings: 0 = Crop killed
10 Full tolerance, no crop injury
CWeed Control Ratings: 0 = No effect on weeds
10 = All weeds killed
Weed species: B1 = Broadleaf weeds (ragweed, cutleaf eveningprimrose,
Gr = Grass weeds (narrowleaf signalgrass, crabgrass,
- 33 -
Table 2.- Cucumber Weed Control.
Treatment Crop Weed Controlc
Herbicide Rate Timinga Tolerance L E R S G A
Bensulide 4* PPI 10 6 2 2 7 8 8
6* 9 6 3 4 8 8 9
naptalam 5+3 9 7 3 5 8 9 8
Trifluralin 3/4 9 5 3 3 7 6 1
Nitralin 1* 9 6 4 3 6 8 0
DCPA 10-1/2d Pre E 8 9 4 3 9 9 5
Naptalam 5* 9 7 ---- 7 .
Amiben ester 2 10 8 5 8 8 9 9
3 9 9 4 9 9 10 9
Amiben ester +
diphenamid 1-1/2+ 3 9 8 6 6 8 10 7
Check -- --- 10 0 0 0 0 0 0
Notes: *Treatments registered for grower use.
aTiming: PPI = Pre=plant incorporated.
Pre E = Pre-emergence to crop
Crop Tolerance Ratings: 0 = Crop killed
10 = Full tolerance,
CWeed Control Ratings: 0 = No effect on weeds.
10 = All weeds killed.
no crop injury.
L = Lambsquarters
E = Cutleaf eveningprimrose
R = Ragweed
S = Narrowleaf signalgrass
G = Goosegrass
A = Annual sedges
This treatment is registered for post-emergence use only.
- 34 -
Table 3.- Snap Bean Weed Control.
Treatment Crop Weed Controlc
Herbicide Rate Timing Tolerance Ns As B1 Gr
EPTC 3* PPI 10 8 8 7 8
Trifluralin 3/4* 10 4 4 4 8
Nitralin 1* 10 2 4 5 6
CDEC 6* Pre E 10 6 10 10 6
CDEC + CDAA 3 + 3* 10 6 10 9 7
propachlor 3 + 2 9 7 10 10 9
Alachlor 2 10 5 10 8 9
"3 10 8 10 9 10
nitrofen 1 + 2 Cracking 8 5 8 7 8
diphenamid 1-1/2 + 2 10 5 6 8 8
2,4-DEP 1-1/2+2 9 7 8 9 8
alachlor 1-1/2 + 2 10 8 8 9 9
naptalam 1-1/2 + 3 9 8 8 8 8
amiben 3+1-1/2 10 5 8 9 9
Check --- --- 10 0 0 0 0
Notes: Treatments registered for grower use.
PPI = Pre-plant incorporated.
Pre E = Pre-emergence to crop and
Cracking = At cracking stage (early
emergence) of crop.
Crop Tolerance Ratings: 0 = Crop killed.
10 = Full Tolerance, no crop injury.
CWeed Control Ratings: 0 = No effect on weeds.
10 = All weeds killed.
Weed species: Ns = Nutsedge
As = Annual sedges
B1 = Broadleaf weed species (lambsquarters, ragweed,
Gr = Grass weed species (narrowleaf signalgrass,
- 35 -
Table 4.- Onion Weed Control.
-Treatment Crop Weed Controlc
Herbicide Rate Timinga Tolerance B Gr
CDAA 6* Pre E 4 10 10
Chlorpropham 4* 9 10 9
DCPA 10-1/2* 10 6 7
DCPA + chlorpropham 5 + t1 10 9 8
BAS-2903 3 10 10 9
S4 9 10 9
Nitrofen 6 6 10 10
Nitrofen 4* Post E 8 10 7
S6 7 10 8
Check -- --- 10 0 0
Note: *Treatments registered for grower use.
aTiming: Pre E = Pre-emergence to crop and weeds.
Post E = Post-emergence (early after emergence)
bcrop Tolerance Ratings: 0 = Crop killed.
10 = Full tolerance, no crop injury.
CWeed ControlRatings: 0 = No effect on weeds.
10 = All weeds killed.
Weed species: Bl = Broadleaf weed species (cutleaf eveningprimrose,
Gr = Grass weed species (narrowleaf signalgrass,
- 36 -
Other studies in progress involve the following:
Weed control in beets.
Weed control in celery on peat soil.
Weed control in sweet corn and field corn.
Weed control in soybeans.
Weed control in caladiums.
Herbicide persistence in sand and peat soils.
Screening of new herbicides.
Collection and identification of Florida weed species.
Onion variety trials.
Use of foam for: Frost protection
Wind and abrasive sand protection
Herbicide drift control.
WEATHER DATA FOR FALL AND WINTER SEASON
Month Avg. Low Avg. High Avg. Rainfall
1971-72 October 64.2 87.5 76.8 6.33
November 54.2 79.4 66.8 4.53
December 58.4 79.3 68.8 3.02
January 55.7 77.7 66.7 2.26
February 47.8 68.1 57.9 5.00
1970-71 October 67.5 85.2 76.3 2.40
November 48.5 75.4 62.9 0.85
December 46.9 76.9 62.4 1.40
January 47.7 73.1 60.4 1.30
February 47.4 76.6 62.0 4.77
March 48.4 76.9 62.6 2.33
Average October 65.3 83.8 74.5 4.48
November 56.5 77.0 66.7 1.73
December 51.3 72.8 62.0 2.01
January 49.9 71.9 60.9 2.04
February 51.2 73.4 62.3 2.40
March 53.9 77.4 65.6 3.69