Dover AREC Research Report DOV 87-1
Central Science
.:7 Library ;:
MAR 19 1987
University of Florida
STRAWBERRY FIELD DAY PROGRAM
February 1 1, 1 87
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E. E. Albregts, C. M. Howard and W. E. Waters, Editors
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Agriculture Research & Education Center
Institute of Food and Agricultural Sciences
University of Florida
Dover, Florida
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AGRICULTURAL RESEARCH & EDUCATION CENTER
INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES
UNIVERSITY OF FLORIDA
DOVER, FLORIDA
Dover AREC Research Report DOV87-1 February, 1987
STRAWBERRY FIELD DAY PROGRAM
February 11, 1987
E. E. Albregts, C. M. Howard and W. E. Waters, Editors
PROGRAM PARTICIPANTS
W. E. Waters, Center Director (GCREC-Bradenton)
J. M. Davidson, Dean of Research (Gainesville)
A. J. Overman, Nematologist (GCREC-Bradenton)
J. F. Price, Entomologist (GCREC-Bradenton)
J. P. Gilreath, Weed Scientist (GCREC-Bradenton)
C. D. Stanley, Soil Scientist (GCREC-Bradenton)
R. L. Mitchell, Extension Agent, Hillsborough County
G. A. Clark, Extension Agricultural Engineer (GCREC-Bradenton)
C. M. Howard, Plant Pathologist (AREC-Dover)
E. E. Albregts, Soil Scientist (AREC-Dover)
Rick Mitchell, Hillsborough County Extension Agent Moderator
1:30 4:00 P.M.
Assembly and Registration
Dr. W. E. Waters, Welcome and Introduction
Dr. J. M. Davidson, Overview of IFAS Research Programs
Prof. A. J. Overman, Solarization/Sorghum Cover/Fumigation
Dr. J. F. Price, Pesticides for Insect and Mite Control
Dr. J. P. Gilreath, Weed Control in Row Middles
Dr. C. D. Stanley, Water Requirements and Drip Irrigation
Dr. G. A. Clark, Tailwater Recovery Ponds
Dr. C. M. Howard, Strawberry Breeding, Variety Trials, and Diseases
Dr. E. E. Albregts, Fertilizer Injection
Nitrogen and Potassium Rates
Slow Release Fertilizer
Container Grown Transplants
Freeze Protection
TABLE OF CONTENTS Page No.
WELCOME AND INTRODUCTION, W. E. Waters ............................. 1
SOLARIZATION/SORGHUM COVER/FUMIGATION, A. J. Overman ................ 2
PESTICIDES FOR NEW INSECT AND MITE CONTROL PRACTICES,
J. F. Price ........ .................. ........................... 3
WEED CONTROL IN ROW MIDDLES OF MULCHED STRAWBERRIES,
J. P. Gilreath ......................................... ... .. 4
WATER REQUIREMENTS AND DRIP IRRIGATION FOR STRAWBERRIES,
C. D. Stanley ....................................................... 6
TAILWATER RECOVERY PONDS IN STRAWBERRY PRODUCTION,
G. A. Clark ....................................................... 8
STRAWBERRY BREEDING PROGRAM, C. M. Howard ........................... .10
STRAWBERRY VARIETY TRIALS, C. M. Howard ............................. 11
CONTROL OF STRAWBERRY DISEASES, C. M. Howard ........................ 13
FERTILIZER INJECTION VS FERTILIZATION AT MULCHING,
E. E. Albregts ...................................................... 17
EFFECT OF NITROGEN AND POTASSIUM RATES ON FRUIT QUALITY,
E. E. Albregts ...................................................... 18
A SLOW RELEASE FERTILIZER, E. E. Albregts ........................... 19
EFFECT OF CHILLING AND DAYLENGTH ON CONTAINER TRANSPLANTS,
E. E. Albregts ...................................................... 20
FREEZE PROTECTION FOR STRAWBERRY, E. E. Albregts .................... 21
WELCOME AND INTRODUCTION
W. E. Waters, Center Director
On behalf of the faculty and staff, I extend to each of you a most cordial
welcome to the Dover Agricultural Research and Education Center. The Center
was initiated in 1927 as a one-man operation located southeast of Plant
City. In 1963 the Center was moved to its present location, and the
programs were expanded. This Center, with an affiliated Agricultural
Research Center located in Bradenton, is a Research and Education unit of
the University of Florida's Institute of Food and Agricultural Sciences.
In Dover and Bradenton, 5 research scientists and 3 extension specialists
participate in strawberry research and extension programs. Each research
scientist also holds a joint appointment with his subject matter department
at the University of Florida. This combination of a broad base of research
disciplines, industry contacts and an excellent faculty makes the
interdisciplinary cooperative team approach to research problems far more
productive than could otherwise be accomplished with limited investments in
independent programs.
The overall mission of these Centers deals directly with the strawberry
industry in Florida through research programs in (1) genetics, breeding and
variety development and evaluation; (2) biological, chemical and mechanical
pest control; (3) production efficiency, culture, fertilization, management
and environmental stress; (4) mechanization, harvesting, handling, and
postharvest physiology; (5) food quality, safety and utilization practices;
(6) water management and conservation; (7) advancement of basic knowledge of
the various scientific disciplines represented by the faculty; and (8)
assistance to the cooperative extension service, departments in the College
of Agriculture and other Research Centers with extension, educational
training and cooperative research programs for the benefit of producers,
consumers and students.
Information presented in this publication summarizes the active research and
extension projects under way this season on strawberries. We sincerely
appreciate your interest and support of these programs, and continuously
solicit your suggestion for improvement, and welcome input concerning
industry needs to keep our research and extension programs productive.
SOLARIZATION/SORGHUM COVER/FUMIGATION
A. J. Overman
Location: Block 2
Objective: To evaluate, for the second- year, 9 weeks of summer soil
solarization versus a summer cover crop of sorghum for berry production..
Soil solarization is a method of heating the soil by sealing the surface
under clear polyethylene film so that the sun's radiation can penetrate the
soil.
Cultivar: Dover
Treatments:
Plot No.
Treatments
1 Solarization plus fumigation
2 Solarization w/o fumigation
3 Cover crop plus fumigation
4 Cover crop w/o fumigation
Method of operation:
1985
1986
June 10 4.0 mil clear polyethylene sealed over rototille
plots.
June 11 Redlan x Greenleaf sorghum seeded.
Aug. 12 Plastic removed.
Aug. 14, 22, 28 Field rototilled.
Sept. 24 Sorghum plots fumigated with methyl bromide and
(MBC 98/2) at 300 Ibs/A.
Oct. 15 Dover plants set.
d field
chloropicrin
July 7 4.0 mil clear polyethylene sealed over rototilled field pL
July 7 Redlan x Greenleaf sorghum seeded.
Sept. 10 Plastic removed.
Sept. 10, 17 Field rototilled.
Oct. 1 1/2 sorghum plots fumigated, 1/2 solarized plots fumigated
with methyl bromide and chloropicrin (MBC 98/2) at 300 lbs/A.
Oct. 20 Dover plants set.
ots.
Results:
1985 1. The sting nematode was equally low in solarized and
sorghum/fumigated plots early in plant season.
2. At harvest the sting nematode was greater in the solarized plots.
3. After last harvest no difference in sting nematode populations
between treatments.
No root-knot nematodes in the field.
:. Solarization resulted in the same berry yields as the sorghum
cover crop followed by soil fumigation.
- "' '""
.
PESTICIDES FOR NEW INSECT AND MITE CONTROL PRACTICES
J. F. Price
Location: Block 13
Introduction: The choices among pesticides to control insects and mites
affecting Florida's strawberries change from season to season according to
the pests present, availability of pesticides, changes in susceptibility to
pesticides, registrations of new pesticides and other reasons. For example,
Kelthane, often chosen for twospotted spider mite and cyclamen mite control
became unavailable to growers this season. The strawberry entomology
program evaluates new pesticides in comparison to existing ones to provide
data supporting new registrations and to form a basis for growers to select
the most appropriate pesticides.
Objective: To evaluate new pesticides for usefulness in controlling insects
and mites affecting strawberries.
Cultivar: Dover
Treatments:
Plot No. Pesticide Amount/100 gal
1 Untreated check
2 Plictran 1 Ib
3 Savy 1 oz a.i.
4 Avid 8 oz
5 BAS 276 00 I 0.25 Ib a.i.
Method of operation: Various pesticides are applied at prescribed
intervals. Insect and mite populations and graded yields are monitored
weekly during the fruiting period.
Results: Results will be presented as they become available.
WEED CONTROL IN ROW MIDDLES OF POLYETHYLENE MULCHED FRUITING STRAWBERRY
J. P. Gilreath
Location: Block 9
Introduction: During the 1985-86 production year the herbicides in the
present test were found to produce no injury to strawberry plants when
applied to row middles. None of the preemergence herbicides controlled
Carolina geranium. Goal provided excellent control of evening primrose (a
winter annual) and hedyotis whereas the other herbicides did not. Grass
control was good with Devrinol and Goal at midseason after one application.
In the spring, after two applications of the preemergence herbicides and one
application of paraquat to plots treated with herbicides which have no
postemergence activity, weed control was excellent with Cinch while Devrinol
and Goal provided poor control. Fair control was obtained with Nortron,
whereas remaining treatments performed poorly. This year herbicides were
applied after plant establishment to reduce leaching losses which were a
factor last year.
Objective: To evaluate herbicides for weed control and crop injury in row
middles of mulched strawberries.
Cultivar: Breeding line 79-1126
Treatments:
Plot No
Herbicides
Rate
(lb. a.i./A)
Method of
application
Weedy check
Devrinol +
Paraquat +
X-77
Nortron +
Paraquat +
X-77
Cinch +
Paraquat +
X-77
Goal +
Agridex
Cinch +
Goal +
Agridex
Goal +
Fusilade 2000 +
Agridex
Fusilade 2000 +
Blazer +
Agridex
2.0
0.5
0.25%
2.0
0.5
0.25%
0.75
0.5
0.25%
0.5
1. %
0.75
0.5
1 %
0.5
0.25
1 %
0.25
0.50
1 %
postemergence
tank mix
postemergence
tank mix
postemergence
tank mix
postemergence
postermergence
tank mix
postemergence
tank mix
postemergence
tank mix
Method of operation: At the time of first application, strawberry plants
were well established and weeds were about 2 to 3 inches tall. Thus, row
middles were sprayed with paraquat (to kill existing weeds) in addition to
preemergence herbicide at the time of the first application in cases where
the herbicide has no postemergence activity. Data are being collected for
weed control and crop response, including yield, during the season.
Additional applications are to be made at timely intervals.
WATER REQUIREMENTS AND DRIP IRRIGATION
FOR STRAWBERRY PRODUCTION
C. D. Stanley, E. E. Albregts, F. S. Zazueta, and G. A. Clark
Location: Block 1
Objectives: 1) To determine, by using field-located drainage lysimeters
and evaporation pan data, the water requirements of
fruiting strawberries.
2) By using different water application rates to determine
effect on fruit production, determine acceptable method for
predicting water requirements.
Cultivar: Dover
Treatments:
Plot No. Soil moisture tension levels
1. A-i, B-i, C-1, D-i -0.1 bars
2. A-2, B-2, C-2, D-2 -0.2 bars
3. A-3, B-3, G-3, D-3 -0.3 bars
4. A-4, B-4, C-4, D-4 -0.4 bars
Methods of operation: In the spring and summer of 1986, 16 lysimeters (8' x
2' x 2 1/2') were installed. Water suction (drainage) and water irrigation
lines (drip) were installed to all lysimeters and are functional. Water
will be automatically applied and then drained into storage tanks to
measure. Four soil moisture levels (-0.10, -0.20, -0.30, and -0.40 bars)
will be maintained in the lysimeters as measured by switching tensiometers.
Sixteen plants have been set in each lysimeter. Large portable rain
shelters constructed of clear plastic can be installed for weekend rain
protection. These will set 18" off the ground to allow air movement. In
addition, an automatic rain shelter as designed by Dr. Gary Clark (Agr.
Engr., Bradenton) is now being constructed and will be in place by next
year.
Results: The original design for this study utilized 30-gallon plastic
containers as lysimeters. The limited number of strawberry plants that
could be grown in these containers prompted the revised design discussed
above. Irrigation treatments last season were proportional to the measured
open pan evaporation (0.75, 1.0, 1.5 times pan).
During the 1985-86 season the evapotranspiration for each treatment varied
with the amount of water applied. Applied amounts of irrigation water are
shown in Table 1. The fruit yields increased with increasing water
application rates but differences were not significant (Table 2).
Considerable variation in fruit yield occurred among lysimeters within a
treatment. Some damage, occurred on an early March weekend when no one was
available to cover plots and sufficient rain fell to flood some lysimeters.
Plant damage was variable and thus yield results were variable. Water use
did not vary greatly except in the most severely flooded lysimeters.
Table 1. Average ml or acre
through April 14, 1986.
inches/lysimeter used by plants from Jan. 1
Treatment
% of pan Jan Feb March April Total
0.75 ml 3489 7023 13361 8360 32233 b
acre/inches 0.679 1.367 2.600 1.627 6.272
gallon/acre/day 595 1326 2353 3156
1.0 pan 2785 7915 14430 11843 36972 b
acre/inches 0.542 1.540 2.808 2.305 7.194
gallon/acre/day 475 1493 2460 4470
1.5 ml 5594 12698 27253 19679 65224 a
acre/inches 1.089 2.471 5.303 3.829 12.694
gallon/acre/day 954 2396 7427
Table 2. Fruit yield/lysimeter (3 plants) in grams.
Treat- ml Fruit
ments % Jan Feb March April Total Ibs/ Water/g size
of pan No. Wt. No. Wt. No. Wt. No. Wt. No. Wt. acre fruit grams
0.75 1 17 24 320 16 238 6 66 57 641 11295 50.29 13.64
1.00 0 0 15 243 24 387 6 73 45 703 12388 52.59 15.62
1.50 2 33 24 368 24 373 11 115 61 889 15665 73.37 14.57
TAILWATER RECOVERY PONDS IN STRAWBERRY PRODUCTION
G. A. Clark, F. S. Zazueta, C. D. Stanley, and E. E. Albregts
Location: Two Grower Fields
Introduction: Tailwater generally refers to runoff from a field which
originated from an irrigation system or from precipitation. A tailwater
recovery system usually consists of a pond and a system of ditches, drainage
tiles, or both used to route runoff water into a pond. The pond would then
be used to store the water until it was needed for the next irrigation
cycle. At times the current storage of the pond may not meet the irrigation
demand level and supplemental groundwater pumping may be necessary.
However, because the tailwater recovery system reduces the volume of runoff
water leaving a field, the volume of groundwater pumpage is reduced and the
efficiency of the water management system is increased.
Fruiting strawberries require irrigation for plant establishment (to
minimize stress levels associated with transplanting), to meet the climatic
evaporative demand, and for frost and freeze protection. Large quantities
of water may be required to meet the demands of the aforementioned
irrigation practices. Therefore, there may be periods when the existing
groundwater supply may not be able to meet the demand rate without adverse
effects associated with the lowering of groundwater levels. Recovery ponds
used as an irrigation reservior can minimize these effects.
Water quality is another concern with respect to recovery ponds. Nutrient
enriched runoff from a field may be captured and recycled, thereby reducing
the gross nutrient input while maintaining optimal production levels.
Another quality problem involves insect and disease control. In other words
could a pond harbor disease problems and promote spreading through the
irrigation system? This study involves evaluation of recovery ponds with
respect to water quantity and water quality.
Objective: The objectives of this study can be placed into two classes,
earlier studies and future work.
A. Earlier Studies:
1) To determine the quantity of water being harvested from an
area with a recirculation pond system.
2) To determine the effect of recycling on water quality.
3) To determine if the recirculation system will promote the
increase of insect and/or disease problems with respect to
the strawberry plants and the fruit.
B. Future Work:
1) Perform detailed field data collection with respect to
identifying all aspects of inputs and outputs (surface flow,
subsurface flow, pumpage, rainfall, evaporation, etc.).
2) Quantify the water saving associated with a recovery pond
system and identify factors contributing to the overall
reduction of groundwater pumpage for irrigation.
3) Investigate the benefits/disadvantages associated with the
'system such as insect activity, water quality,
geologic/topographic limitations, and economic
considerations.
4) Develop a model using collected field data and use this model
to predict the behavior of a recirculation/harvesting system.
5) Establish pond design criteria and guidelines based on field
and model results.
6) Develop and promote extension education programs aimed at
strawberry growers interested in using a tailwater recovery
water management system.
Results: Three seasons of data were collected on strawberry production
fields. The first two years involved 25 acres of strawberries. The field
year involved a different grower with a similar recycling facility and 8
acres of strawberries, Groundwater withdrawals varied throughout each
season and were attributed to varied amounts and distribution of rainfall
from one season to another. As would be expected, subsurface drainage was
reduced during the drier portions of the growing season. Reduced drainage
levels were observed with the third production site. This site was operated
during a drier year and about 30% of the production area did not contain a
subsurface spodic layer. Therefore a confining or semi-confining layer will
enhance the water harvesting potential of a field.
Soluble salts of the drainage water decreased from the time of transplanting
during the first two seasons. This was attributed to the uptake of
fertilizer by the strawberry plants. Drainage water nitrate concentrations
decreased with time from planting. Potassium concentration changes were
much slower and of lower magnitude than the nitrates. Nutrient levels
applied from the pond ranged from 25 to 53 #/Ac for NO3, 1 to 3 #/Ac for
NH4, and 29 to 51 #/Ac for K. These values represent seasonal quantities.
STRAWBERRY BREEDING
C. M. Howard
Location: Blocks 3, 4 and 12
Objectives: To develop new strawberry varieties which are specifically
adapted to Florida growing conditions.
Method of operation:
First year (Block 4): Crosses are made in the greenhouse during the winter,
and seeds are sown in flats in late March or early April. Seedlings are
transplanted into individual peat pots in May or early June and set in the
nursery in late June where they form runners. In October, clones are
selected from the nursery on the basis of runner production and resistance
to anthracnose, leaf spot and leaf blight. Two plants of each selection are
transplanted into the fruiting field where records are kept on fruit yield
and other characteristics. Specific clones are selected primarily on the
basis of appearance, ripening characteristics, yield, earliness, and fruit
size. Emphasis is also placed on selecting for long, large diameter, single
fruit stems to improve uniformity of fruit size and ease of harvest.
Second year (Block 3): The clones that have been selected are transplanted
into the summer nursery where they are again observed for runner production
and resistance to anthracnose. In October, selections are made from this
group and transplanted into 10-plant observation plots. In this trial, the
clones are compared with currently grown varieties, and the fruit and plants
are observed more closely for any defects such as poor color and soft fruit.
Specific clones are selected on the basis of plant type, early and total
fruit yield, type of fruit stems, fruit firmness, color, size, ripening
characteristics and general appearance. These clones are transplanted into
the nursery in April where they are again observed for runner production and
resistance to diseases (especially anthracnose).
Third year (Block 12): The most promising clones from the second year
observational trials are placed in replicated trials where they can be
thoroughly compared with varieties currently being grown in Florida. After
a clone has shown sufficient promise for at least three years in replicated
trials, a variety release committee may be formed. If the committee after
reviewing all the accumulated data, agrees that the specific clone should be
an improvement over currently grown varieties, then the clone can be named
and released as a new variety.
STRAWBERRY VARIETY TRIAL FOR 1986-87 SEASON
E. E. Albregts and C. M. Howard
Location: Block 12
Objective: To evaluate all promising breeding lines and out-of-state
varieties for earliness, yield, fruit size, ripening characteristics, and
plant growth characteristics.
Treatments: Breeding lines and cultivars being evaluated are shown below.
No. Clone No. Clone No. Clone
1. 79-1126 11. 83-414P 21. 84-2260
2. 81-1350 12. 83-37P 22. 84-1665E
3. 81-2465Y 13. 83-4017 23. 84-1528
4. 81-2689EY 14. 83-5P 24. 84-1932P
5. 82-1452P 15. 83-3349 25. 84-2433E
6. 82-594EYP 16. 83-3385P 26. Miss. 74
7. 82-1565 17. 83-457 27. Douglas
8. 82-1556P 18. 83-428 28. Pajaro
9. 82-1656EY 19. 83-418 29. Selva
10. 82-67YG 20. 83-118P
STRAWBERRY VARIETY TRIAL (CONT'D)
Results: Yields of marketable fruit from selected clones in 1985-86 trial.
Cultivar Av. wt. of
or line Jan Feb March April Seasonal mktble fruit
Marketable yield (flats/A) g/fruit
81-2689EY 528 1195 1338 227 3289 17.87
81-2465Y 41 731 1346 190 2307 14.43
81-1350 379 962 794 387 2523 16.19
82-1452P 141 972 1351 186 2653 16.02
82-594EYP 222 957 1123 267 2569 18.17
82-1556P 93 785 1634 245 2756 16.48
82-576Y 236 1207 1322 600 3364 16.35
83-4017 158 654 1786 140 2738 15.06
83-3349 138 1061 1389 415 3003 14.69
83-3385P 84 663 1722 347 2816 16.62
83-457 169 833 1628 154 2783 14.47
83-428 68 511 1478 278 2334 12.63
83-118P 10 482 958 411 1861 16.03
Chandlerb 386 334 990 509 2219 15.55
Pajaro 67 711 591 359 1727 17.08
Selvab 262 422 690 272 1647 15.33
aThirty breeding lines were tested but data are shown only for 13 of the
most promising lines.
bChandler and Selva plants were grown in Canada and; therefore, would be
expected to have early yields. All other plants were locally grown.
CONTROL OF STRAWBERRY DISEASES
C. M. Howard
Location: Block 5
Objective: To evaluate fungicides for control of fruit anthracnose and to
determine the tolerance of the plants to the fungicides.
Cultivar: Pajaro
Treatments:
Plot No. Treatments
1. Untreated check
2. Captan 50W 6 Ibs/A twice/wk in 100 gal/A.
3. Captan 50W 6 Ibs/A once/wk in 200 gal/A.
4. Difolatan 80S 2 lbs/A twice/wk.
5. Uniroyal UBI A-815 50W 0.25 lbs/A twice/wk.
6. Uniroyal UBI A-815 50W 0.5 lbs/A twice/wk.
7. Captan 50W 6 Ibs/A once/wk in 100 gal/A.
8. Thiram 75W 3 lbs/A twice/wk in 100 gal/A.
9. Bravo 720 2.25 pts/A twice/wk.
10. Phaltan 50W 2 lbs/A twice/wk.
11. Benlate 50W 1 lb/A twice/wk.
12. Spotless 25W 0.3 lb/A twice/wk.
Location: Block 5
Objective: To evaluate fungicides for control of gray mold fruit rot and to
determine the tolerance of the plants to the fungicides.
Cultivar: Dover
Treatments:
Plot No. Treatments
1. Untreated check.
2. Captan 50W 6 lbs/A twice/wk.
3. Captan 50W 6 lbs/A twice/wk until disease occurs then six
applications of Rovral 50W 1 lb/A once/wk + Captan 50W
6 lbs/A once/wk.
4. Captan 50W 6 Ibs/A twice/wk until disease occurs then six
applications of Rovral 50W 1.5 Ibs/A once/wk + Captan 50W
6 Ibs/A once/wk.
5. Captan 50W 61bs/A twice/wk until disease occurs then six
applications of Rovral 50W'2 Ibs/A once/wk + Captan 50W
6 Ibs/A once/wk.
6. Captan 50W 6 Ibs/A twice/wk until disease occurs then six
applications of Ronilan 50W 1.5 Ibs/A once/wk + Captan 50W
6 lbs/A once/wk.
7. Uniroyal UBI A-815 50W 0.5 lb/A twice/wk.
8. Benlate 50W 1 Ib/A once/wk.
9. Phaltan 50W 2 Ibs/A twice/wk.
10. Spotless 25W 0.3 Ib/A twice/wk.
CONTROL OF ANTHRACNOSE ON STRAWBERRY FRUIT
C. M. Howard
Objective: To evaluate fungicides for control of anthracnose on strawberry
fruit and to determine the tolerance of the plants to the fungicides.
Cultivar: Pajaro
Treatments: Fungicides were applied from 16 Dec., 1985 through 14 April,
1986.
Results:
Treatment and
rate/A
Difolatan 80S 2 lbs
Captan 50W 6 Ibs
Captan 50W 6 Ibs
Thiram 75W 3 lbs
Phaltan 50W 2 lbs
Topsin-M 50W 1 lb
Benlate 50W 1 lb
Check
Rovral 50W 1 lb
Ronilan 50W 1.5 lb
Rovral 50W 1.5 lbs
Rovral 50W 1.5 lbs
Spray
interval
(days)*
3-4
3-4
7
3-4
3-4
3-4
3-4
14
7
14
7
Marketable
yield
(flats/A)
1286 a -**
828 b
794 bc
707 bc
706 bc
675 bcd
598 cde
494 def
459 ef
432 ef
416 ef
385 f
Yield of ripe fruit
with anthracnose
(flats/A)
644 abc**
762 a
721 ab
748 a
629 abc
655 abc
714 ab
440 cd
484 bcd
438 cd
281 d
428 d
*Spray intervals listed as 3-4 indicate sprays
with alternating 3 and 4-day intervals.
**Values within a column followed by the
significantly at the 0.05 level according to
Test.
were
applied twice per week
same letter do not differ
Dunca's New Multiple Range
CONTROL OF ANTHRACNOSE ON STRAWBERRY FRUIT
R. L. Mitchell, C. M. Howard, & Carl Groomsa
Objective: To evaluate fungicides for control of anthracnose on strawberry
fruit and to determine the tolerance of the plants to the fungicides.
Cultivar: Pajaro
Treatments: Fungicides were applied 7, 11, 16, 19, 21, 24, 28 March and 1,
5, 11 April, 1986.
Results:
Marketable Yield of ripe fruit % by wt of ripe
Treatment yield with anthracnose fruit with
and rate/A (flats/A) (flats/A) anthracnose
Captec 4L 2.5 qts. 643 a* 441 abc** 40.7 ab*
Bravo 75W 2 lbsb 633 a 308 a 32.7 a
Phaltan 50W 2 lbs 556 ab 460 abc 54.4 bc
Ridomil MZ-58 2 Ibs 543 ab 499 abcd 47.8 bcd
Difolatan 80S 2.5 Ibs 484 ab 388 ab 44.5 bc
Dyrene 50W 4 Ibsb 482 ab 438 abc 44.6 bcd
Manzate 200 80W 2.5 Ibs 457 ab 503 abcd 52.4 cd
Thiram 75W 2.5 Ibs 370 bc 496 abcd 57.3 d
Control 272 c 678 d 71.4 e
Rovral 50W 1.5 lbs 236 c 601 bcd 71.8 e
Cyprex 65W 2 lbs 215 c 591 bcd 73.3 e
Benlate 50W 1 lb 201 c 622 cd 75.6 e
aCarl Grooms provided the area where this trial was conducted and provided
the labor to apply the fungicides and harvest the fruit.
bBravo caused mild to moderate foliage burn and Dyrene caused severe foliage
burn, (Foliage burn consisted of dying and drying of large areas of
leaflets.)
"Numbers within columns followed by the same letter are not significantly
different according to Dunca's multiple range test (P=0.05).
FERTILIZER INJECTION VS FERTILIZATION AT MULCHING FOR STRAWBERRY
E. E. Albregts
Location: Block 6
Objective: To compare fertilization by the injection wheel with dry
application prior to mulching.
Cultivars: 'Dover' on south half and breeding line 79-1126 on north half of
plots.
Treatments:
Number of Total nitrogen
Plot Application Fertilizer* Applica- and potassium
No. Method Source tions (K70) Ibs/A
1. At mulching (a) Dry 1 100
2. At mulching (a) Dry 1 150
3. At mulching (a) Dry 1 200
4. Injection wheel (b) Liquid 4 100
5. Injection wheel (b) Liquid 4 150
6. Injection wheel (b) Liquid 4 200
7. 1/2 a + 1/2 b Both la, 2b 100
8. 1/2 a + 1/2 b Both la, 2b 150
9. 1/2 a + 1/2 b Both la, 2b 200
10. a + b Both la, Ib 140
11. a + b Both la, lb 190
12. a + b Both la, lb 240
VDry fertilizer was a 10-4-10 and liquid fertilizer was an 8-0-8; phosphorus
was applied preplant.
Method of operation: Treatments 4, 5, and 6 were fertilized on Nov. 17,
Dec. 15, Jan. 15, and March 2 at 10, 20, 35, and 35%, respectively, of total
amount applied, treatments 7, 8, and 9 received 1/2 of liquid fertilizer on
Jan. 15, and the remainder on March 3; and treatments 10, 11, and 12
received liquid fertilizer on March 1 (40 Ibs N&K20).
Results: Previous work indicated that injection of liquid fertilizer into
bed could substitute for dry fertilizer application at mulching.
EFFECT OF NITROGEN AND POTASSIUM RATES ON FRUIT QUALITY
E. E. Albregts
Location: Block 7
Objective: To determine if high rates of nitrogen and potassium would
affect strawberry fruit quality.
Cultivars: 'Pajaro' on south half and breeding line 79-1126 on north half
of each plots.
Treatments:
Potassium rate (lbs/A')
400
800
Method of operation: One-fourth of nitrogen and potassium fertilizer was
applied broadcast and 3/4 banded in bed center 2 inches deep. Phosphorus
was applied broadcast at 50 lbs/acre of P205.
Results: Previous results with high rates of nitrogen indicated that 200
lbs/acre %N was generally sufficient for optimum yields and effect on fruit
quality varied with cultivar. Potassium fertilizer rates above 150 lbs/acre
% elemental K have reduced fruit size while fruit yields have decreased
slightly.
Pl n-
100
200
400
800
400
P1 n .- N^ Njtnanrnt ( sA) otss -u-------m -rat (ls/A
N;+rnoPn ra+p (Iha/AI
SLOW RELEASE FERTILIZER
E. E. Albregts
Location: Block 8
Objective: To determine if "Melamine" fertilizer will enhance early yields
of strawberry.
Cultivars: 'Dover' on south half and breeding line 79-1126 on north half of
plots.
Treatments:
Plot
Standard
Special fertilizer
No. Fertilizer (Ibs/acre) Material Rate (Ibs/A)
1. 200N-45P205-200K20 None
2. 200N-45P205-200K20 Melamine phosphate 150
3. 200N-45P205-200K20 Melamine 80
4. 152N-34P205-152K20 Melamine 80
Method of operation: One-fourth of the standard fertilizer and all of the
special fertilizer was broadcast. The remainder of the standard fertilizer
was banded in bed center 2 inches deep.
Results: Previous work on other crops indicated that "Melamine" enhanced
early yields.
1"Melamine phosphate", a 16-42-0 fertilizer, and "Melamine", a 60-0-0
fertilizer, are slow release materials. "Melamine" is a ureaform, and
releases its nitrogen very slowly. "Melamine phosphate" is a "Melamine"
coated phosphate material. Both nitrogen and phosphorus are released
slowly.
EFFECT OF CHILLING AND DAYLENGTH ON CONTAINER GROWN TRANSPLANTS
E. E. Albregts
Location: Block 11
Objective: To evaluate container grown transplants for effect of chilling
and daylength on plant establishment and fruiting response.
Cultivars: "Dover' on south half and breeding line 79-1126 on north half of
plots.
Treatments:
Plot
No Chilling Daylength Planting date Container cell size
1. 2 wks 10 hours October 7 1 1/2" x 2 1/2"
2. 2 wks 10 hours October 7 1 3/4" x 2 1/2"
3. 2 wks 10 hours October 7 2" x 3"
4. 2 wks 10 hours October 21 1 1/2" x 2 1/2"
5. 2 wks 10 hours October 21 1 3/4" x 2 1/2"
6. 2 wks 10 hours October 21 2" x 3"
7. None 10 hours October 7 1 1/2" x 2 1/2"
8. None 10 hours October 7 1 3/4" x 2 1/2"
9. None 10 hours October 7 2" x 3"
10. None 10 hours October 21 1 1/2" x 2 1/2"
11. None 10 hours October 21 1 3/4" x 2 1/2"
12. None 10 hours October 21 2" x 3"
13. None In nursery October 7 None
14. None In nursery October 21 None
Method of operation: Plants receiving chilling were held in a cooler at 32
- 40oF. Plants in treatments 13 and 14 were dug and set the same day and
received normal irrigation for establishment while all other treatments
received sprinkler irrigation 3 or 4 times a day for 5 to 15 minutes during
the first week.
Results: If the root ball remained intact, the plant established easily
with little overhead sprinkler irrigation. Previous tests resulted in
enhanced early yields with 2 weeks of chilling and 10 hour days given before
transplanting into fruiting beds.
FREEZE PROTECTION FOR STRAWBERRY
E. E. Albregts, Craig Chandler & Gary Clark
Location: Block 10
Objective: To evaluate various
flowers and fruit.
methods of freeze protection for strawberry
Cultivar: Douglas
Treatments:
Plot No. Bed cover & wt.
Foam
Overhead sprinkler
Kimberly Clark
International paper
Dupont heavy
Dupont light
Control
Kimberly Clark
International paper
Dupont heavy
Dupont light
Control
Kimberly Clark
Kimberly Clark
Dupont light
Dupont light
Dupont heavy
Dupont heavy
None
None
None
None
No
No
No
No
No
No
No
No
No
No
No
Yes
No
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
No
No
No
No
No
No
No
No
No
Method of operation: All treatments have standard fertilizer, fumigation,
and mulch practices. Bed covers and foam were applied prior to each freeze
and removed when that freeze event was past. Thermocouples were placed on
flowers in selected beds during a freeze to monitor the flower temperatures.
Treatments 17, 18, 19 and 20 have different thickness of foam and amount of
air in foam.
Results: Previous research has demonstrated that a Kimberly Clark bed cover
does give considerable protection to flowers and fruit during a freeze.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
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