• TABLE OF CONTENTS
HIDE
 Front Cover
 Table of Contents
 Main














Group Title: Field day activities (Agricultural Research and Education Center (Hastings, Fla.))
Title: Field day activities.
ALL VOLUMES CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00076395/00003
 Material Information
Title: Field day activities.
Physical Description: Serial
Publisher: Agricultural Research and Education Center,
Publication Date: 1990
 Record Information
Bibliographic ID: UF00076395
Volume ID: VID00003
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: 145913417 - OCLC

Table of Contents
    Front Cover
        Front Cover
    Table of Contents
        Table of Contents
    Main
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
Full Text











ACTIVITIES


AGRICULTURAL RESEARCH AND EDUCATION CENTER

HASTINGS, FLORIDA





APRIL 19, 1990


HASTINGS AR:C RESEARCH REPORT HAS1990-1


lD C:e


30TH F I E L D


DAY



















PROGRAM 30TH FIELD DAY

AGRICULTURAL RESEARCH AND EDUCATION CENTER
Hastings, Florida

THURSDAY, APRIL 19, 1990, 1:00 PM

Presiding Jim Dilbeck, St. Johns County Extension Director


D. R. Hensel, Center Director,
Welcome, Announcements, Potato Outlook

Page
J. R. Shumaker, Assoc. Prof., AREC Hastings
Potato Variety Trials
Potato Chip/Snack Food Association Trial 1
Advanced Trials 1
Generation Studies 4
Cultural Management Studies on 6
Onions, Broccoli, Cabbage, and Potatoes

D. R. Hensel, Center Director
Cooperative Fertilizer Trials 10
Gel Suspension Trials 13
Calcium and Nitrogen Supplements 15
Nutrient Sprays 16
Potato Growth Model 17

D. P. Weingartner, Assoc. Prof., AREC Hastings
Summaries of Recent Studies
Experiments in Progress in 1990 18
Fungicide Trials 23
Bacterial Wilt 24
Nematode Control 25
Cabbage Diseases 27

Break
Tour of Plots
Refreshments courtesy of ASGROW FLORIDA CO., SWIFT FARM CENTER,
HELENA CHEMICAL CO. and WISE FOODS.






Potato Variety Development
J. R. Shumaker, Assoc. Professor


I. Potato Variety and Seedling Evaluation

A. The Snack Food Association Test:

The Snack Food Association has sponsored regional potato chip
trials in 7 locations in the U.S. California, Pennsylvania,
Michigan, Red River Valley, Washington, Maine, and Hastings,
Florida. The trials are designed to evaluate potential chip
varieties for their adaptability in terms of yield and size
distribution, specific, gravity, and chip quality. For this test,
50 pound samples of each clone were provided by the breeder.
The trial is conducted on a mini-commercial scale to simulate
commercial cutting, handling and planting of seed. The crop
was planted on Jan. 24, and is now 85 days old. Following is
a list of clones being currently evaluated in Bed 18 OL. The
results of the 1989 test are also included.


Clone Clone Clone
Atlantic (check) Norchip (check) ND 2008-2
MS 700-83 MS 716-15 NY 85
La Belle AF 875-16 Saginaw Gold
Coastal Chip WIS 855 B9792-8B
CS 7232-4


B. Advanced Replicated Intermediate and Observational Tests:

In these tests potato clones are evaluated in small plots (20
ft.) in either advanced replicated tests (4 replications of each
clone) or intermediate tests (2 replications of each clone).
Emphasis is placed on testing for superior yields, quality and
pest resistance. Data will be collected and evaluation made
of the following variables: vine types and vigor of the plants,
tuber types, maturation, yields, specific gravity, chip color
and pest resistance. The tests were planted on Jan. 29 and are
currently 80 days old. Following is a list of the tests, the
number of entries being evaluated and the location of each test.
A list of the clones entered in the Advanced Round White and
Red test is also included.

Test Entry Location
Advanced Round White or. Red 49 Bed 8 NL Rows 2-10
Intermediate Round White or Red 91 Bed 8 NL Rows 11-15 and
Bed 7 NL Rows 2-6
Advanced Russet 10 Bed 7 NL Rows 7-10
Intermediate Russet 13 Bed 18 OL Rows 11-15


-1-










Results of 1989 Potato Chip/Snack Food Associations Test -- Hastings, FL


Under Pick
Clone 1 7/8 outs US 1A Grand Specific
(Size B) (Size A) 1 7/8-2 1/2" 2 1/2-3" 3-3 3/4" Total No. 1 total gravity

------------------------------ cwt/A ------------------------------------
W 855 24 8 212 92 9 313 345 1.080
NY 72 -9 9 123 112 57 292 310 1.073
AC 80545-1 10 19 129 104 23 256 285 1.065
Somerset .8 13 120 106 19 245 266 1.071
Atlantic 8 12 113 107 22 242 262 1.083
B 9792-8B 17 10 165 54 5 224 251 1.073
Saginaw Gold 24 13 180 34 0 214 251 1.074
La Belle 6 32 72 103 31 206 244 1.073
MS 700-83 19 13 149 46 5 200 232 1.065
Norchip 12 10 118 57 11 186 208 1.074
AF 875-16 16 15 152 28 2 182 213 1.082
MS 716-15 18 15 146 32 0 178 209 1.074
MS 700-70 12 22 111 40 7 158 192 1.075
D 195-24 14 22 63 2 0 65 101 1.079


-2-







1990 Advanced Round White and Red Test:


Planting No.


Clone


Source


Planting No.


Atlantic

Superior

LA01-38

Sebago

LA12-59 R

Red Norland R

La Rouge R

Atlantic

Norchip

Sebago

Sangre R

Ontario

Hudson

La Rouge R

Superior

Somerset

Redsen R

Sunrise

Denali

Reddale R

Campbell-13

NY81

Red La Soda F

La Chipper

Oceania


'DFA
II

II

It

II

I1

II

MPB
II

II

II

I"

II

1I

II

II

II

II

II
II

II

II
MPB


B0233-1

B0243-7

B0179-17

B0184-18

B9792-8B

B9792-157

NY-72

CS 7635-4

AF 1060-2

AF 828-5

LB 8104-1

CS 7232-4

AF 875-16

FL 657

Jemseg

G76-29

G77-1

FG 6-15

76-31

F24-12

G102-2

F100-1

F12-5

G80-3


R = Red Skin
DFA = Drees Farming Assoc., Grand Forks, ND
MPB = Main Potato Seed Board, Presque Isle, ME
USDA = Beltsville, MD
PA = Wise Food, Berwick, PA
U of M = University of Maine, Aroostook Farms, Presque Isle, ME
CU = Cornell University, Ithaca, NY


Clone


S Source


USDA
II

'I

II

It

II

PA

U of M
II

II

II

II

II

MPB
II

CU
II

II


II

I!

I!

II

II
11


























11

11

11

11

11

11

11

11


Source






II. Generation Studies With Atlantic


With the advent of various tissue cultural techniques applied to
the potato, it has been possible for the seed growing areas to
maintain a high degree of disease free seed. We are currently
evaluating 6 Atlantic generations from the State of Maine for yield
and specific gravity information. The test is 79 days old and
replicated 8 times.


Planted
Generation
Nuclear 3
Nuclear 4
Generation 1
Generation 2
Generation 3
Generation 4


Gen.
from
Mini-tubers


Source
State of Maine Seed Farm
State of Maine Seed Farm
Houghton Farms, Fort Fairfield, ME
Houghton Farms, Fort Fairfield, ME
Houghton Farms, Fort Fairfield, ME
Houghton Farms, Fort Fairfield, ME








Important Notice:
Please disregard the Terminology for Generation form that was included with your Strike It Rich'Seed Packet.
This is an updated version that is correct
TERMINOLOGY FOR GENERATION


STATE


SOURCE
Prior to Field


YEAR 1


YEAR 2


YEAR 3


YEAR 4


YEAR 5


YEAR 6


ALASKA LAB GH GEN I GEN II GEN III GEN IV GEN V GEN VI

CALIFORNIA LAB GH NUCLEAR GEN I GEN II GEN III FOUNDATION CERTIFIED

COLORADO LAB GH GEN I GEN II GEN III GEN IV GEN V GEN VI

IDAHO LAB GH NUCLEAR EUTE I EUTE II EUTE III FOUNDATION CERTIFIED

MAINE LAB GH NUCLEAR I NUCLEAR II NUCLEAR III GEN I GEN II GEN III

MICHIGAN LAB GH NUCLEAR III GEN PREMIER
GEN II FOUNDATION FOUNDATION CERTIFIED

MINNESOTA LAB GH NUCLEAR GEN I GEN II GEN III GEN IV GEN V

MONTANA LAB GH NUCLEAR GEN I GEN II GEN III GEN IV

FOUNDATION
NEBRASKA LAB GH NUCLEAR GEN I FOUNDATION
NEBRASKA LAB GH NUCLEAR GENGEN II GEN III FOUND. Approved CERTIFIED

FOUNDATION FOUNDATION FOUNDATION FOUNDATION
NEW YORK LAB GH (Seed Plot) (Uihlein Farm) Uihlein I Uihlein II Uihlein III FOUNDATION

NORTH DAKOTA LAB GH NUCLEAR GEN I GEN II GEN III GENIV GEN V

OREGON LAB GH NUCLEAR GEN I GEN II GEN III GEN IV GEN V

UTAH LAB GH NUCLEAR GEN I GEN II GEN III GEN IV

WISCONSIN LABGH UNIVERSITY FARM FOUNDATION FOUNDATION FOUNDATION FOUNDATION
WISCONSIN LAB GH UNIVERSITY FARM E I EN III I
GEN I GEN II GEN III GEN IV



CANADA LAB GH PRE-ELITE EUTE I ELITE II EULITE 111 FOUNDATION CERTIFIED


I






Cultural Management Studies to Increase Plant Populations
on Onions, Broccoli, Cabbage, and Potatoes

J. R. Shumaker, Assoc. Professor
D. R. Hensel, Center Director

Sweet onions would have a unique market window if'produced in Hastings.
They could be harvested a few days earlier than Vidalia, Georgia due
to warmer climate and less severe winters. Grown successfully, this
would help the Hastings area diversify our economy should potatoes
suddenly become less profitable.

Current Georgia legislation defines the sweet onion grown in Vidalia
as "all existing yellow hybrid Granex varieties". Both Granex 33 and
429 :eets this requirement and grows well in Florida. Granex 33 is
early, sweet, mild, and a preferred variety for Georgia production from
transplants. Granex 429 is several days later than Granex 33 with a
deeper shape and corresponding potential for larger sizes and higher
yields. Texas Granex type (502, 1015, 1025) and other short-day varieties
will also grow well in Florida.

One of the problems in onion production over the years has been to
increase plant populations successfully. Difficulties are encountered
in transplanting 2 rows of onions on the standard 40 inch row used in
Hastings. Problems exist in getting a transplanter to plant the second
row without disturbing the first row. The number of plants on a single
40 inch row with a 5 inch spacing is about 31,364 which is generally
too low to be efficient. This year an attempt was made to increase
the population by making a double wide bed and planting 3, 4, and 5
rows of onions. Figure 1 shows the bed arrangement. With the mechanics
in place, the principle was extended to cabbage, broccoli, and potatoes
with different fertilizer treatments to determine if the standard amounts
were sufficient for the increased populations.

Table 1 gives the information on standard practices and variables in
the four separate experiments. Both the onion and potato experiments
are in progress while the broccoli and cabbage experiments were harvested
several weeks ago. Results of the broccoli experiment are presented
in Table 2.

Information gained from these experiments will help direct the course
of future work in this area.












Figure 1.




ONION PLANT SPACING TRIAL


-i 4"'~- -i ~~" ;i ~14.61;1 ~CII"

I~ I
/ / I 71 I -I ~


/ I I I

I / I I I
/ ./ / I I I r r r




/ r
, I
I I
I I I I
/ I I I
I I
/ / / I
I Ilr
/ I I I
/ I I I r
/ / / /r

/ II I
r I
r I I

/ / I Ir
I I I I r
/ / r I I r
I I r I I

I I
/ / / I r





r
/ /r
I I r r
I I

/ I
I I
I I r
/ I r


-7-





Table 1. Plant Population/Fertilizer Trial on Various Vegetable Crops--Hastings, FL 1989-90.

Crop


Material/Procedure Cabbage

Cultivar A&C #5 Plu
Transplant/Plant Date 11/16-17/8

Tractor Setting 80" Centers

(1) Standard Single 40 inch Rows
Between Row Spacing 40"
In-Row Spacing 10"
No. Transplants-Seed/A(X) 15,682

(2) One 60" Bed (Multiple Rows)
No. Transplants-Seed/A
3 Rows (1.5X) 23,523
4 Rows (2.OX) 31,364
5 Rows (2.5X)

Basic Fertilizer Application (Lbs/A) 60-48-144

Supplemental treatments 0-0-0
50-0-0
100-0-0


s
9


Replications


S--


----


1/ Assumes 2 oz. seed pieces.


Broccoli

Green Belt
11/16-17/89




40"
10"
15,682




23,523
31,364


60-48-144

0-0-0
50-0-0
100-0-0


4


Onion

Granex #429
12/13-14/89




40"
5"
31,364




47,046
62,728
78,410

100-48-144

0-0-0
50-0-0
100-0-0


4


Potato

Superior
2/16/90




40"
8"
2,450 Ib1/




3,675 Ib1/




168-28-168

0-0-0
75-0-0
0-0-75
75-0-75

4










Table 2. Effect of Bed Configuration and N
Fertilization on Broccoli Yields. 1989-90.


Row/bed


Supplemental N

0 .-
50
100


Mean


N
0
50
100

Mean*


Bed Size
40" 80"
1 3 4

Crates/A (23 Ibs)

162 198 207
202 319 371
218 382 405

194 y 299 z 328



Head Wt. (Ibs)


0.28
0.37
0.37


0.22
0.35
0.43


0.15
0.30
0.33


0.34 z 0.33 z 0.26 y


*Means separated
significant at 5%


by different letter designates
level.


Overall
Mean*

189 c
297 b
335 a


0.22
0.34
0.38







Cooperative Fertilizer Trials

D. R. Hensel, Center Director


Cooperators:


Kidder, Acting Chair, Soil Science
J. Hochmuth, Assoc. Professor, Vegetable Crops
D. Dilbeck, County Extension Director, St. Johns.County
A. Tilton, County Extension Director, Putnam County
E. Schrader, County Extension Director, Flagler County


This is the third year of the cooperative fertilizer trials. The
experiment/demonstration is being conducted at 4 locations in the
tri-county area. In addition to the AREC site, similar tests are located
on grower fields in each county. The tests are site specific. Soil
tests for each site determine the basic fertilizer level. Both nitrogen
and potassium rates are varied to test the validity of the original
amounts used. A grower practice at each site was included for comparison.
The 1990 treatments at AREC Hastings are:


Treatment
1
2
3
4
5
6
7
8


Planting
100-0-0
150-0-0
200-0-0
150-0-0
150-0-0
150-0-45
150-0-90
168-28-168


Sidedress
50-0-0
75-0-0
100-0-0
75-0-0
75-0-0
75-0-25
75-0-50
60-10-60


Total
150-0-0
225-0-0
300-0-0
225-0-0
225-0-0
225-0-70
225-0-140
228-38-228


An additional application
except treatment 4 if a
planting.


of 30-0-20 was to be applied to all plots
leaching rain occurred before 70 days after


Table 1 gives results of 1989 at the four locations.


-10-







Table 1. Yield Results of 1989 Fertilizer Trials.
Area Fertilizer Total Yields Specific
Farm Treatment (Cwt/A) Gravity
Flagler 150-0-70 240 1.083
County 225-0-70 240 1.083
Baylor 300-0-70 266 1.083
Farm 225-0-70 271 1.082
225-0-0 224 1.085
225-0-80 262 1.083
225-0-160 289 1.080
112-40-128z 264 1.079
Significant NL* Trt vs Ck*
differences KL** KL**




Area Fertilizer Total Yields Specific
Farm Treatment (Cwt/A) Gravity
Putnam 150-0-70 311 1.080
County 225-0-70 278 1.080
Revels 300-0-70 268 1.079
Farm 225-0-70 303 1.081
225-0-0 274 1.083
225-0-80 282 1.081
225-0-160 273 1.079
98-0-98 z 213 1.075


Significant
differences


Trt vs Ck**
NL**


Trt vs Ck**
N vs K*


Fertilizer
Treatment
150-0-140
225-0-140
300-0-140
225-0-140
225-0-0
225-0-80
225-0-160
160-110-300z


Total Yields
(Cwt/A)
368
344
346
346
340
344
350
290


Significant
differences


Trt vs Ck**
NL*


Trt vs Ck**
KL**
KL


-11-


Area
Farm
St. Johns
County
Smith
Farm


Specific
Gravity
1.077
1.076
1.079
1.077
1.081
1.078
1.076
1.070







Table 1, continued


Area
Farm
AREC
16 OL


Fertilizer
Treatment
150-0-140
225-0-140
300-0-140
225-0-140
225-0-0
225-0-80
225-0-160
228-12-228


Total Yields
(Cwt/A)
238
215
200
203
205
209
217
209


NL**
NL


Significant
differences


*Significant at 5% level
Significant at 1% level
z Grower treatment


-12-


Specific
Gravity
1.080
1.083
1.084
1.083
1.083
1.084
1.080
1.081

NL*
KL
KQ








Comparison of Gel Type Suspensions to Liquid Nitrogen Solutions
as Nitrogen Fertilizers on Potatoes and Onions

D. R. Hensel, Center Director

Cooperator: S. J. Locascio, Professor, Vegetable Crops

Liquid nitrogen solutions have been utilized by the agricultural industry
for many years. They offer many advantages in terms of ease of handling
applications and are readily available to the plant. Since the nitrogen
is completely in solution it is also subject to leaching. By converting
the liquid nitrogen into a gel, possibly it may be not as mobile and
less subject to leaching from heavy rains. Lyndal Corporation of Dalton,
Georgia supplied three experimental products for this test. These
products, when small amounts are mixed with nitrogen solutions, form
gel-suspensions which can be pumped and handled like regular solution.
The gels tend to be stable over long periods of time and may reduce
the nitrogen contact with soil solution.


Potatoes

In the potato experiment, 3 products were added to regular Uran solutions
which formed gels. These were compared to regular nitrogen solutions
and dry formations. The following list gives the name of products and
percent nitrogen used in the experiment.


Materials % N Rate N Ibs/A

Uran Solution only 28 125, 225
Uran + REAP R-100 (1.1%) 28 125, 225
Uran + REAP R-531 (0.8%) 28 125, 225
Uran + REAP R-532 (1.1%) 28 125, 225
Dry Urea/NH4NO3 125, 225


All materials were applied to potatoes at planting after a basic
application of 0-25-50 Plots were four rows wide, 25 feet long, and
arranged in a randomized block design 4 replications.

'Potato growth and development will be monitored during the growing season
while yield and quality will be determined at harvest. Soil and plant
tissue samples will be taken to determine if relative leaching losses
exist.


-13-







Onions

Some of the same material used in the potato experiment was superimposed
over some onions which had already been fertilized with 110-48-144
overall. In addition, the following treatments were applied:


Material
Uran + REAP R-531 (0.8%)
Uran Solution
NH4NO3 (dry)
Check


% N
28
28


N rates Lbs/A
125, 225
125, 225
125, 225


Above treatments were applied in randomized block design having 3
replications. Rows were single row onions on 40 inch beds. Spacing
was approximately 5 inches between plants. Plots were 4 rows wide and
25 ft. long. Varieties in this test were Granex 33 and 429. Onions
will be evaluated for quality and yield in respect to fertilizer
treatments.


-14-







Calcium and Nitrogen Supplements for Potatoes


D. R. Hensel, Center Director

Calcium requirement of potatoes has been fairly well documented. In
recent years, no confirmed calcium deficiency on potatoes has been found
in the Hastings area. Liming of soils with dolomite has been routine
and generally soils test high in available calcium. Research by Wisconsin
and other places report that if additional calcium is placed in the soil
near the tuber initiation zone, it enhances the growth and development
of potatoes. Some growers in the Hastings area have been applying gypsum
(CaSO4) during the growing season. Also a product containing 9.0% nitrogen
and 9.0% calcium called N-Hib has been marketed as a liquid supplement
for potatoes.

This experiment is a preliminary test to determine the potential of using
Ca and N supplements in the tuber zone. The following table gives the
materials and amounts of Ca and N applied:


Amount Applied Ibs/A
Materials N Ca
Check 0 0
Gypsum 0 28
Gypsum 0 56
Gypsum + NH4NO3 28 28
Gypsum + NH4NO3 56 56
N-Hib (30 gallons) 28 28
N-Hib (60 gallons) 56 56


Plots are 4 rows wide replicated 4 times and arranged in randomized block
design. Seed pieces were lightly covered and materials were hand applied
to the top of the beds. After application of the treatment materials,
the plots were covered in a normal manner. Growth and development of
the potatoes will be evaluated to determine the direction of future work.


-15-






Nutrient Spray and Specific Gravity
Relationships on Potatoes

D. R. Hensel, Center Director

In the potato chipping industry, specific gravity of tubers is a very
important factor. This factor is closely related to the amount of oil
needed for frying, frying time, and amount of chips produced from a
given weight of raw product. The higher the specific gravity the more
chips can be produced. There has been some evidence from time to time
that nutrient sprays cause the specific gravity to increase. This is
a preliminary study to determine if that relationship exists for the
Hastings Florida growing area.

Potatoes were planted using basic fertilizer application of 168-28-168
on all plots. Additional sidedressing of 60-10-60 was applied at 30
days after planting. Wuxal Suspension Tuberl/ was applied in three
separate applications starting at early bud formation with repeat
applications at 2 and 4 weeks later. The three applications supplied
18 pints/A for all treatments. The treatments are as follows:


Spray application Pints/A of Wuxal"

1st 2nd 3rd Total
0 0 0 0
6 6 6 18
8 5 5 18
5 8 5 18
5 5 8 18

Wuxal Analysis by wt.

% %
N 10.0 Fe 0.1
Mg 3.9 Mn 1.4
S 3.6 Mo 0.0005
B 0.02. Zn 0.05
Co 0.0005 Cu 0.05

Plots are 4 rows wide and 25 ft long. Each set of 4 rows has 2 adjacent
'dummy rows which accommodate a sprayer with off-set boom in order to
reduce injury to plants by repeated applications. Yield and specific
gravity and other quality measurements will be taken at harvest to
determine treatment effects.




1/ Made by Aglukon Agri-Products Nor-Am Chemical Company


-16-







Potato Modeling Experiment


Cooperators: D. R. Hensel, Center Director
G. Kidder, Acting Chair, Soil Sciences

This project is part of an international study to develop a computer
model on how the potato plant grows and responds to various factors.
The model tries to account for environmental factors such as sun light,
temperature, soil type and other factors that influence growth.

In Hastings, we are developing minimum data sets to be entered into the
overall computer model. Prediction curves will be compared to the observed
experimental data to verify the data set. When the model is complete,
one should be able to use it -to tell how potatoes would grow not only
in Florida but any other state or country.

The name for this project is International Benchmark Sites Network for
Agrotechnology Transfer (IBSNAT) and uses a computerized Decision Support
System for Agrotechnology Transfer (DSSAT). The primary location of
the project is at the University of Hawaii in Honolulu. There are
cooperators located in many parts of the world. Cooperators are evaluating
varieties, disease control methods, and a multitude of other factors
besides fertility.

Potatoes were planted in a regular fertility trial with nitrogen and
potassium as variables. Data are being taken throughout the growing
season and at harvest. These include leaf area, number of tubers, size,
weight, and specific gravity along with weather information. All of
these factors will be transferred to the central computer which will
be used to develop the model and its verification.

Since each treatment requires a large amount of data collection, the
total number of treatments were limited. Three rates of nitrogen were
applied at 0, 100, and 200 Ibs/A. and two rates of K20 were 0 and 75
Ibs/A. A randomized block with 4 replications was the design. Plots
were 27 ft. long and 4 rows wide.


-17-






Disease and Nematode Control -
Summaries of Selected Recent Experiments and Experiments in Progress.
D. P. Weingartner, Assoc. Professor

Early blight

Early blight caused by Alternaria solani is generally considered to be a
disease of senescing plants and a disease with a comparatively slow
to moderate rate of increase. In recent seasons, however, early blight
has been severe in northeast Florida potatoes even in relatively immature
plants. Heavy losses in yield have been sustained when the disease
has not been controlled. Research emphasis during the past several
years has been directed towards defining the relationship of early
blight epidemics to yield and .specific gravity in different potato
cultivars, developing sufficient epidemiological and meteorological
data relative to crop losses for devising a spray advisory system for
early blight, and evaluation of fungicides and fungicide application
schedules for control of the disease.

Selected data from fungicide experiments performed during 1987, 1988,
and 1989 are summarized in Tables 1, 2, and 3. Early blight was severe
during each season. During 1987 (Table 1) all of the fungicide
treatments except Ridomil MZ 58 (1) effectively controlled early blight.
The difference in early blight control between the two Ridomil MZ58
treatments was due to Ridomil MZt'58 (1) being applied without
supplemental applications of mancozeb whereas Ridomil MZ"58 (2) was
followed by five applications of Dithane M-45. During both 1988 (Table.
2) and 1989 (Table 3), Bravo 720 and Rovral provided the best
season-long control of early blight.

Although there were significant differences in early blight control
among fungicides and between fungicide treatments and the control during
each season all differences in yield of U.S. Size A tubers were
nonsignificant (P = 0.05).


Table 1. Percentage early blight and tuber yields in La Rouge
potatoes as affected by different fungicide applications during 1987.1/

Yield size
% Early blight A tubers
Funqicide 5/12 5/18 cwt/A

Bravo 720 1.6 a 2.7 a 137
Dithane M-45 2.3 a 7.2 a 124
Ridomil MZ58 (1) 2.6 ab 49.6 b 113
Ridomil MZ58 (2) 4.1 c 5.3 a 135
Rovral 50 WP 3.6 bc 3.7 a 131
Control 4.1 c 45.8 b 100


-18-










Table 2. Percentage early blight and tuber yields in La Rouge
potatoes as affected by different fungicide applications during 1988.1/

Yield size
% Early blight A tubers
Fungicide 5/6 5/9 5/17 5/24 cwt/A


Bravo 720
Dithane M-45
Rovral 48 SC
Rovral 50 WP


1.2
1.7
1.2
1.2


4.4
36.0
3.0
15.2


37.1
83.9
7.5
74.5


Control I Z.J. 5.5 a 83.b e luU.U a ZdU




Table 3. Percentage early blight and tuber yields in Atlantic and
Sebago potatoes as affected by different fungicide applications
during 1989.1/
Yield size
% Early blight A tubers
Fungicide 4/19 4/25 5/5 5/10 5/15 cwt/A

Dithane M-45 2.6 8.0 50.2 b 58.4 b 92.4 b 106
Bravo 720 2.9 4.2 23.6 a 22.3 a 61.3 a 111
Rovral 4SC 1.9 3.4 21.8 a 30.4 a 75.9 ab 122
Control 1.6 5.9 91.6 c 94.9 c 99.9 b 101
1/ Values within a column followed by the same letter do not differ
significantly (P = 0.05) according to Duncan's multiple range
test. Lack of letter denotes nonsignificance.


-19-







2/Summary of application dates, nozzle arrangements and other spray details.

1987 Bravo 720 applied with two overhead nozzles at 0.75 pints (9
oz ai) on 7, 14, 21, 28 April; then six nozzles at 1.5 pint
(18 oz ai) 5, 12, 19, 26 May. Dithane M-45 was applied on
the same schedule as Bravo 720 at 1.5 lb (.1.2 lb ai) per acre.
Ridomil MZ58 (1) was applied 7 and 21 April at 20 Ib/acre
[metalaxyl 10% (32 oz ai) + mancozeb 48% (15.4 oz ai)]. Ridomil
MZ 58 (2) was applied as (1) and was then followed with
applications of Dithane M-45 at 1.5 lb 28 April, 5, 12, 19,
and 26 May. Rovral was applied at 2.0 lb (1.0 lb ai) per acre
on 5, 12, and 19 May. All fungicides except Bravo 720 were
applied with six nozzles per row.

1988-- Dithane M-45/Bravo 720, -and- Rovral 48 SC were applied--7,
13, 21, 27 April; 5, 11, and 18 May. Dithane M-45 was applied
at 1.5 lb per acre; Bravo 720 at 1.0 lb ai. Rovral 50 WP
was applied 21 April and 5 May at 1.0 lb ai. Bravo 720 was
applied with three nozzles per row in 50 gallons water whereas
all others were applied with six nozzles and 100 gallons water.

1989 Bravo 720 and Dithane M-45 were applied 12, 18, 27 April and
3 and 9 May. Rovral 4 SC was applied 12 and 27 April. All
were applied with six nozzles per row. Bravo and Rovral were
applied at 1.5 pint (18 and 12 oz ai, respectively) and Dithane
M-45 at 1.5 lb per acre.


The effects of early blight on tuber yields and specific gravity has
been evaluated in nine different potato cultivars. Yields and specific
gravities in fungicide-sprayed and nonsprayed plots of Atlantic, Sebago,
Superior, and La Chipper are summarized in Tables 4 and 5. Although
early blight data are not shown, it was the major cause of defoliation
in the three experiments and as determined by regression analyses,
the most important factor affecting the differences in yield and specific
gravity.

Losses in yield associated with early blight varied substantially within
each season and cultivar (Table 4). Losses in Atlantic ranged from
12.3% in 1988 to 45.7% in 1987 an( averaged 31.6% during the three
year period.

Reductions in specific gravity reflect a decrease in total solids due to
early blight. The average respective percentage loss in total solids
-among Atlantic, Sebago, Superior, and La Chipper during the three years
was 4.9, 5.2, 4.5, and 3.8%.


-20-








Table 4. Yields of U.S. Size A potato tubers and
percentage yield loss due to early blight and
defoliation in four potato cultivars during 1987,
1988, and 1989.

Cultivar and
early blight Yields of U.S. Size A
control/ tubers (cwt/acre)

1987 1988 1989 Mean

Atlantic

+.control 175 301 195 224
control 95 264 123 161
% loss2/ 45.7 12.3 36.9 31.6

Sebago

+ control 106 309 165 193
control 91 288 128 169
% loss 14.2 6.8 22.4 14.5

Superior

+ control 76 272 169 172
control 69 267 87 141
% loss 9.2 1.8 48.5 19.8

La Chipper

+ control 95 289 192
control 77 266 172
% loss 18.9 7.9 13.4


1/ + control = Weekly applications of chlorothalonil
at 1.5 pint/acre. control = no fungicide applications.
- control plots were 100% defoliated by harvest during
each year. Early blight was the major disease each year,
however, some portion of defoliation was undoubtedly due
to other causes such as drought, wilt organisms, and un-
identified foliage pathogens. The relationship of early
blight to yield was verified through correlation and
regression analyses.
2/ loss = (Yield of + control) (Yield control) X 100
Yield + control


-21-







Table 5. Specific gravities of U.S. Size A potato tubers
of four cultivars as affected :by early blight control.


Cultivar and
early blight
control I/


Spec ific
1987 1988


gravity
1989


Mean


Atlantic


+ control
control

Sebago
+ control
control

Superior
+ control
control

La Chipper
+ control
control


1.077 1.083 1.078 1.0793
1.073 1.078 1.073 1.0747


1.058 1.066 1.060 1.0613
1.054 1.063 1.055 1.0573


1.074 1.073 1.070 1.0723
1.070 1.070 1.066 1.0687


1.067 1.071
1.064 .1.068


-1.0690
-1.0660


1/ + control = Weekly applications of chlorothalonil at
1.5 pint/acre. control = No fungicide applications.
- control plots were 100% defoliated by harvest during
each year. Early blight was the major disease each year,
however, some portion of defoliation was undoubtedly due
to other causes such as drought, wilt organisms, and un-
identified foliage pathogens. The relationship of early
blight to yield was verified through correlation and
regression analyses.


-22-







Five early blight experiments are in progress during 1990. Incidence
of early blight in these plots on 16 April 1990 was very low. A few
lesions, however, are present in some nonsprayed controls.

Fungicide efficacy experiment I. Bed 12 New Land. Various Bravo
720 (chlorothalonil) and Rovral 4SC (iprodiohe) treatments and
application schedules are being compared in Atlantic and Sebago
cultivars. The test was planted 8 February and the first fungicide
applications were made 29-30 March. This study is partially funded
by Fermenta and Rh6ne-Poulenc Chemical Companies.

Fungicide efficacy experiment II. Bed 6 Old Land. Two older fungicides,
thiram and ziram, are being compared to Bravo 720. The test was planted
31 January, and Atlantic is the test cultivar. The first fungicide
application made on 29 March. The test is partially funded by a
commercial grant.

Economic assessment of fungicides for early blight control. The
objective of this experiment is to compare relative early blight control
by Bravo 720 (chlorothalonil), Rovral (iprodione), and Dithane M-45
(mancozeb) and the effects of early blight on yields and specific
gravities of three potato cultivars (Atlantic, Superior, and La Rouge)
following use of three rates of each fungicide. An economic assessment
of control by each fungicide will be made. This study is partially
funded by the USDA Southern Region Pesticide Impact Assessment Program.
Planted 1 February. The first fungicide application was made 15 March.

Fungicide Schedules. Beds 1 and 2 New Land. This experiment is a
continuation of tests performed during the past three seasons.
Twenty-seven different fungicide (Bravo 720) application schedules
are being compared for early blight control and effects on yield and
specific gravity. It may be feasible to eliminate all but a few
skillfully timed fungicide applications during the season. The test
was planted 5 February and has Atlantic and Sebago as the test cultivars.
The first fungicide application was made 22 March.

Early blight Florida-Pennsylvania. Bed 11 NL. A comparison of the
effects of early blight on yields and specific gravities of Atlantic,
Sebago, Kennebec, and Superior cultivars is being made between Florida
and Pennsylvania grown potatoes. Identical experiments are being
performed here and in Pennsylvania. The test was planted 5 February.
Dr. Barbara Christ is the cooperating pathologist at Penn State.

Bulking Study. Bed 4 New Land. The bulking period is being studied
in 10 different potato cultivars (Superior, New Superior, Kennebec,
Sebago, Atlantic, La Chipper, Red La Soda, La Rouge, Green Mountain,
and Ontario. The objective is to determine the relationships among
crop bulking period, disease progress of early blight and degree days.
Data from this study, the fungicide schedule experiment and previous
experiments using the above cultivars in previous seasons, will be
coordinated to delineate by degree days when fungicides are needed
to prevent losses in yield and specific gravity due to early blight.
This test was planted 13 February.


-23-






Bacterial Wilt Control


Atlantic is more susceptible to bacterial wilt than is Sebago. Due
to the increased northeast Florida acreage of Atlantic relative to
Sebago the disease has once again become important. Several bacterial
wilt studies are in progress.

Resistance. Bed 4 New Land. Resistance to bacterial wilt in USDA
potato selections has been evaluated since 1987. Approximately 3120
selections were initially screened in the field following artificial
inoculation with the pathogen. Promising clones were multiplied and
re-evaluated in subsequent seasons. Presently 29 clones are being
evaluated. The test was planted 1 February. The first sign of bacterial
wilt was noted 22 March. As of 2 April the number of wilted plants
in 15 of the clones was equal to or less than that of the resistant
standard Ontario. This test is being conducted in cooperation with
Drs. R. W. Goth and K. Haynes with the USDA and Dr. J. R. Shumaker.
It is being partially funded through a USDA grant.

Bacterial wilt-chemical control Bed 4 New Land. Alliette (fosetyl-Al)
is a systemic fungicide which moves upward and downward in plants and
is known principally for control of Phycomycetes (i.e. water molds
and mildew fungi). There is some indication that the chemical may
have efficacy in controlling bacterial diseases. Alliette, a copper
fungicide (Kocide) and mancozeb (Dithane M-45) are being evaluated
alone and in combinations for control of bacterial wilt. The test
was planted 13 February. Bacterial wilt was observed throughout the
test by early April. The experiment is partially funded by
Rhone-Poulenc and is intended to be exploratory in nature.

Bacterial Wilt/Corky Ringspot Varieties Beds 5 and 6 New Land. Twelve
named varieties (Oceana, Hudson, Superior, Sebago, Atlantic, Ontario,
Green Mountain, Red La Soda, La Rouge, New Superior, Kennebec, and
La Chipper) are being re-evaluated for their response to corky ringspot
and bacterial wilt. Two tests are established. One is in nontreated
soil whereas the other is planted in soil previously fumigated with
Telone II at 6.0 gallons/acre in-the-row. The objective of the
experiment is to observe symptom development of the diseases in the
haulm and:in tubers. Dr. J. R. Shumaker, cooperator.


-24-







Nematode Control


Two experiments are in progress.

Long term use of nematicides Beds 3, 4, 5 Old Land. This test has
been in progress since 1977. Different combinations of Temik, Telone
II, and Busan" 1020 and sequences of their use from year to year are
being studied. The test was planted 31 January. Data from 1989 are
summarized in Table 4. During the 13 seasons duration of the test
the average yield of plots treated with Telone II + Temik 15G plots
and the nontreated controls have been, respectively, 234 and 135
cwt/acre. Since 1985 Busan 1020 has been applied at 20 gallons/acre
using two chisels/row. Yield comparisons since 1985 among the different
nematicides are summarized in Table 5.

Nematicide Efficacy Beds 5 and 6 New Land. Mocap 1OG and Temik
15G are being tested at 3, 6, 12, and 1, 2, and 3 lb ai/acre,
respectively. The treatments are superimposed on Telone II at 6.0
gallons/acre in Bed 6 NL and are used singly in Bed 5. The tests were
planted 15 February. Partially funded by Rh'ne Poulenc.

Nematode Increase Beds 6 and 7 Old Land. These beds have not been
treated with nematicides since 1985. Potatoes are planted in the spring
and okra during the summer in order to build up root-knot nematodes.
It is hoped that future funding will be available to study population
dynamics and economic thresholds of root-knot nematodes in potato.


-25-






Table 6. Tuber yields and nematode populations at harvest during 1989 in long-term use of nematicides test.


Plot
No
1
2
3
4
5
6
7
8
9
10
11
12


Yield Size A
tubers (cwt/acre)


Nematicide
treatment/
1988 1989
T+A T+A
T T
T T
CK T+A
A A
A CK
CK CK
T+A CK
T CK
CK T
M+A M
M M+A


Atlantic
255
240
240
237
222
176
141
152
103
170
228
218


Sebago
253
245
186
198
179
98
64
93
57
145
152
148


Nematodes/100 cm3 soil at


Mean
254
243
230
217
200
137
102
122
80
157
190
183


1/ A = Temik 15G at 20 Ib/acre in-the-row; T and M, respectively, were Telone II


TR DO BL MI TY CR
0 9 1 25 1 10
13 8 6 12 53 3
0 20 12 50 20 19
0 5 3 2 4 0
0 13 35 20 53 45
0 19 107 21 77 97
0 1 100 4 164 48
5 28 67 57 154 82
0 17 206 7 178 118
0 3 40 0 85 85
0 2 30 8 69 69
0 5 3 4 17 17


rest 2/


at 6.0 and 20.0 gallons/acre
two chisels/row.


in-the-row. Telone II was injected with one and Busan 1020 with


2/ Nematode codes are: TR = Trichodorus and Paratrichodorus spp, DO = Dolichodorus heterocephalus,
BL = Belonolaimus longicaudatus, MI = Meloidogyne incognita, TY = Tylenchorhynchus claytoni, CR
= Criconemella ornata, PR = Pratylenchus spp, HP = Hopolaimus gracilis. The nematode values shown
are the means of four samples for each nematicide treatment. Total nematodes also include
Hemicycliophora spp.


-26-


harv
PR
2
1
4
0
12
40
1
22
25
5
2
4
and


HP TOTAL
2 51
0 95
0 127
0 13
20 199
1 362
18 335
0 414
0 549
0 168
0 125
0 34
Busan 1020








Table 7. Average tuber yields following the use of different
nematicides during 1985 1989.


Nematicide
treatment
Busan 1020
Busan 1020 + Temik 15G
Telone II
Telone II + Temik 15G
Temik 15G
Nontreated


Rates
per acre
20 gal
20 gal + 20 lb
6 gal
6 gal + 20 lb
20 lb


Tuber
yields
cwt/acrel/
213
230
188
212
188
136


1/ Averaged across all varieties used in the test.






Cabbage Diseases

Cabbage white mold caused by Sclerotinia sclerotiorum has been severe
in certain cabbage fields during the past three seasons. An intensive
study of the development of white mold is being performed at Flagler
Farms in Flagler County.


Alternaria Control Newer fungicides are being compared to standard
in a cabbage seed bed. Partially funded by Rhone-Poulenc.


-27-




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