• TABLE OF CONTENTS
HIDE
 Front Cover
 Field map
 Program
 Table of Contents
 Welcome and introduction
 Current list of program leaders,...
 Mite management
 Strawberry culture
 Strawberry disease control
 Strawberry breeding program
 Water management for strawberry...
 Weed control
 Nematode management for strawb...
 Strawberry field tour
 Acknowledgement
 Map to AREC-Dover






Group Title: Strawberry field day.
Title: Strawberry field day. February 13, 1991.
ALL VOLUMES CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00076494/00008
 Material Information
Title: Strawberry field day. February 13, 1991.
Series Title: Strawberry field day.
Alternate Title: Research report - Dover, Florida Agricultural Research and Education Center ; DOV 91-1
Physical Description: Serial
Language: English
Creator: Albregts, E. E. ( Editor )
Howard, C. M. ( Editor )
Chandler, C. K. ( Editor )
Waters, W. E. ( Editor )
Publisher: Agricultural Research Center, Institute of Food and Agricultural Sciences, University of Florida
Publication Date: 1991
 Record Information
Bibliographic ID: UF00076494
Volume ID: VID00008
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 143121533

Table of Contents
    Front Cover
        Front Cover
    Field map
        Field map
    Program
        Program
    Table of Contents
        Page i
        Page ii
        Page iii
    Welcome and introduction
        Page 1
    Current list of program leaders, appointment date, and area of specialization and location
        Page 2
    Mite management
        Page 3
    Strawberry culture
        Page 3
    Strawberry disease control
        Page 4
        Page 5
    Strawberry breeding program
        Page 6
    Water management for strawberry production
        Page 7
    Weed control
        Page 8
        Page 9
    Nematode management for strawberry
        Page 10
    Strawberry field tour
        Page 10a
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
    Acknowledgement
        Page 23
    Map to AREC-Dover
        Page 24
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AGRICULTURAL RESEARCH AND EDUCATION CENTER
INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES
UNIVERSITY OF FLORIDA

13138 Lewis Gallagher Road
Dover, FL 33527-9664


STRAWBERRY FIELD DAY PROGRAM

FEBRUARY 13, 1991



MODERATOR: D. N. Maynard, Vegetable Extension Specialist, GCREC-Bradenton

Time, PM

12:45 Registration

1:15 Welcome and Introductory Comments W. E. Waters

1:20 Update of IFAS Research Programs Dr. E. R. Emino, Assistant Dean
for Research

1:30 Mite Management J. F. Price

1:45 Irrigation Research C. D. Stanley

1:55 Cultivar Development C. K. Chandler

2:10 Strawberry Diseases C. M. Howard

2:20 Nutrition and Culture E. E. Albregts

2:30 COFFEE/BERRY BREAK

2:40 Tour of Research Plots

Mite Management J. F. Price
Culture E. E. Albregts
Disease Management C. M. Howard
Plant Breeding C. K. Chandler
Irrigation C. D. Stanley

Field Day Hosts and Tourquides:

P. R. Gilreath, Manatee County Vegetable Extension Agent
K. M. Butts, Hillsborough County Vegetable Extension Agent








TABLE OF CONTENTS

Page

Welcome and Introduction .......................................... 1

List of Program Leaders ..................................... ....... 2

USPS Employees ...................................... ................. 2

Strawberry Research Accomplishments

MITE MANAGEMENT

Release of predatory mites for management of two-spotted
spider mite. J.F. Price and M. van de Vrie .................... 3

Dispersion of first generation mites in strawberry fields.
J.F. Price and M. van de Vrie ................................. 3

Effects of various strawberry cultivars and breeding lines on
twospotted mite reproduction. J.F. Price, M. van de Vrie,
and C.K. Chandler ........................................... 3

STRAWBERRY CULTURE

Evaluation of mulch color for fruiting strawberry. E.E.
Albregts ................................................. 3

Effect of N source on strawberry fruiting response. E.E.
Albregts ................................................... 3

Fertilizing the summer nursery. E.E. Albregts ................. 4

Calcium sprays for strawberry. E.E. Albregts .................. 4

STRAWBERRY DISEASE CONTROL

Anthracnose (black spot) on fruit. C.M. Howard ................ 4

Graymold. C.M. Howard ....................................... 5

Anthracnose: Crown to crown spread (field). C.M. Howard ....... 5

Inoculation of roots with anthracnose pathogens. C.M. Howard ... 6

Anthracnose in the nursery. C.M. Howard ....................... 6

Anthracnose: Crown to crown spread (greenhouse). C.M. Howard .. 6








STRAWBERRY BREEDING PROGRAM Page

Cultivar development. C.K. Chandler ........................... 6

Anthracnose resistance. C.K. Chandler and C.M. Howard ......... 7

Propagation study. C.K. Chandler .............................. 7

Stability study. C.K. Chandler ............................... 7

Variance components study. C.K. Chandler ...................... 7

WATER MANAGEMENT

The use of runoff recovery systems for reducing groundwater
withdrawals. C.D. Stanley and G.A. Clark ...................... 7

Water requirements and crop coefficients of strawberries. C.D.
Stanley and G.A. Clark ................................. ........ 8

Using tensiometers to schedule water applications for micro-
irrigated strawberries. C.D. Stanley and G.A. Clark ........... 8

PEST MANAGEMENT

Weed management. J.P. Gilreath ............................... 8

Nematode management for strawberry. A.J. Overman .............. 10

Field Tour

Optimal Period of Release of Predatory Mites J.F. Price and
M. van de Vrie ............................................ 11

Interactions Between Spider Mites and Strawberry Lines and
Cultivars J.F. Price, M. van de Vrie, and C.K. Chandler ...... 11

Demonstration of Biological Control of Twospotted Spider Mite
at AREC-Dover J.F. Price and M. van de Vrie .................. 12

Delaying Fertilization of Fruiting Strawberry E.E. Albregts ........ 12

Nitrogen Rate on Fruit Yield and Quality of Strawberry E.E.
Albregts and C.K. Chandler .................................... 13

Response of Strawberry to Mulch Color E.E. Albregts ................ 13

Strawberry Fruiting Response to Foliage Removal E.E. Albregts ...... 14

Preplant Chilling and Planting Date for Strawberry E.E. Albregts ... 15








Page

Inoculation of Strawberry Buds with Anthracnose C.M. Howard ........ 15

Crown to Crown Spread of Anthracnose Crown Rot C.M. Howard ......... 16

Control of Powdery Mildew C.M. Howard ............................. 16

Control of Gray Mold C.M. Howard ................................. 17

Control of Powdery Mildew with Nova (Rally) C.M. Howard ............ 17

Variety Trials C.K. Chandler and E.E. Albregts ..................... 18

Observational Trial C.K. Chandler ................................ 19

Row Trial C.K. Chandler .......................................... 19

Seedling Trial C.K. Chandler ..................................... 19

Water Requirement and Crop Coefficients of Strawberries G.A.
Clark, E.E. Albregts, C.D. Stanley, A.G. Smajstrla, and
F.S. Zazueta .............................................. 19

Tensiometer Schedule, Drip Irrigated Strawberries G.A. Clark,
E.E. Albregts, C.D. Stanley, A.G. Smajstrla, and F. S.
Zazueta ............................. .......................... 20

N and K Rates for Microirrigated Strawberry E.E. Albregts,
G.A. Clark, and C.D. Stanley ................................... 21

Preplant N and K for Microirrigated Strawberry E.E. Albregts,
G.A. Clark, and C.D. Stanley ................................. 22

Acknowledgements ..................................... ... .... 23








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, 7 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 cultivar
development and evaluation; (2) biological, chemical and mechanical pest
management for diseases, insects, nematodes, and weeds; (3) production
efficiency, culture, fertilization, management and environmental stress; (4)
mechanization, harvesting, handling, and postharvest physiology systems; (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 suggestions for improvement, and welcome input concerning industry needs
to keep our research and extension programs productive.








CURRENT LIST OF


Albregts, Earl E.


Chandler, Craig K.


Clark, Gary A.


Gilreath, James P.

Howard, Charles M.


Price, James F.


Stanley, Craig D.


Waters, Will E.


PROGRAM LEADERS, APPOINTMENT DATE, AND AREA OF
SPECIALIZATION AND LOCATION

1967. Soil Scientist. Local administration, soil and
plant nutrition and culture of strawberry and vegetable
crops, AREC-Dover.

1987. Assistant Geneticist and Plant Breeder. Genetics,
plant breeding, and development of strawberry cultivars,
AREC-Dover.

1986. Assistant Extension Water Management Specialist.
Extension education and cooperative research on vegetable
and ornamental crops, GCREC-Bradenton.

1981. Associate Horticulturist. Weed control of
vegetable and ornamental crops, GCREC-Bradenton.

1967. Plant Pathologist. Etiology and control of
strawberry and vegetable disease, AREC-Dover.

1978. Associate Entomologist. Identification, biology
and control of insects and mites of ornamental and
strawberry crops, GCREC-Bradenotn.

1979. Associate Soil Scientist. Soil-water relations
for ornamental and vegetable crops, GCREC-Bradenton.

1960. Horticulturist and Center Director.
Administration, soil and plant nutrition, and
horticulture, GCREC-Bradenton.


UNIVERSITY SUPPORT PERSONNEL SYSTEM STAFF


Annie F. Turgeau
Alicia J. Whidden
James C. Sumler
Larry J. Smith
Frederick D. Wenzel
Margaret E. Rush
Michael C. Murphy


Secretary
Biological Scientist
Biological Scientist
Agricultural Assistant Supervisor
Senior Agricultural Assistant
Agricultural Assistant
Agricultural Assistant








MITE MANAGEMENT
J. F. Price and M. van de Vrie

Release of the Predatory Mites, Phytoseiulus Persimilis and P. Macropilis for
Management of Twospotted Spider Mite: The two predator species were released
in separate experiments onto plants infested in December, 1989 with
twospotted spider mites. Predator releases were made either one, two or
three times during the early to mid-production period. No insecticides
or miticides were used. Both predator species reduced spider mites well
below densities in untreated checks. A single release was as effective
as two or three releases. Numerous naturally occurring parasites of
insects and predators of insects and mites developed among the plants and
provided additional reductions in mites and insects. There were no
measurable differences in period of fruit production or amount of fruit
produced.

Dispersion of First Generation Phytoseilus Persimilis in Strawberry Fields:
Phytoseiulus persimilis predators of twospotted spider mite were released
in commercially grown strawberry fields. Strawberry leaves were observed
for 1 week at distances up to 100 feet from points of release. Predators
were found up to 75 feet away from release points. Active walking by
predators probably accounts for only a portion of the distance travelled.
Insects, birds, air currents, field equipment or workers may have accounted
for the longer distances of mite movement.
Effects of Various Strawberry Cultivars and Breeding Lines on Twospotted Spider
Mite Reproduction (with C.K. Chandler): Twospotted spider mites were reared on
leaves of fruiting 'Chandler', 'Pajaro', 'Dover', 'Selva', 'FL83-37',
'FL82-1452', 'FL84-1932' and 'FL79-1126' strawberry plants. Longevity of
females and numbers of eggs produced per female did not vary among the
cultivars and lines. 'Selva' leaves expressed damage and at lower mite
densities than did any other cultivar or line.

STRAWBERRY CULTURE
E. E. Albregts
Evaluation of Mulch Color for Fruiting Strawberry: During the 1989-90 season,
black polyethylene was mulched over fumigated and fertilized beds. Beds
were then painted with oil base paint in colors of white, yellow, orange,
red, green, brown, blue, or left unpainted. 'Chandler', 'Selva', and Fla.
breeding line 'FL79-1126' were set in all beds. Highest seasonal yields
were obtained from plots mulched with white, yellow, orange and green
mulches. White and yellow mulches resulted in higher average fruit weight
while dark colored mulch resulted in the lowest average fruit weight.
Plots with yellow mulch gave lowest percent marketable fruit because of
more rotten fruit. Soil temperatures at the one and four inch depths in
the plant beds at 2 PM were lowest with the white and yellow mulches.
Early morning soil temperatures were not influenced by mulch color.
Effect of N Source on Strawberry Fruiting Response: During the 1989-90 season,
methylene urea (40% N), sulfur coated urea (37% N), and (NH4)2 S04 coated
with urea formaldehyde (32% N) were applied to plant beds which were
fumigated with methyl bromide and mulched'with black polyethylene.








MITE MANAGEMENT
J. F. Price and M. van de Vrie

Release of the Predatory Mites, Phytoseiulus Persimilis and P. Macropilis for
Management of Twospotted Spider Mite: The two predator species were released
in separate experiments onto plants infested in December, 1989 with
twospotted spider mites. Predator releases were made either one, two or
three times during the early to mid-production period. No insecticides
or miticides were used. Both predator species reduced spider mites well
below densities in untreated checks. A single release was as effective
as two or three releases. Numerous naturally occurring parasites of
insects and predators of insects and mites developed among the plants and
provided additional reductions in mites and insects. There were no
measurable differences in period of fruit production or amount of fruit
produced.

Dispersion of First Generation Phytoseilus Persimilis in Strawberry Fields:
Phytoseiulus persimilis predators of twospotted spider mite were released
in commercially grown strawberry fields. Strawberry leaves were observed
for 1 week at distances up to 100 feet from points of release. Predators
were found up to 75 feet away from release points. Active walking by
predators probably accounts for only a portion of the distance travelled.
Insects, birds, air currents, field equipment or workers may have accounted
for the longer distances of mite movement.
Effects of Various Strawberry Cultivars and Breeding Lines on Twospotted Spider
Mite Reproduction (with C.K. Chandler): Twospotted spider mites were reared on
leaves of fruiting 'Chandler', 'Pajaro', 'Dover', 'Selva', 'FL83-37',
'FL82-1452', 'FL84-1932' and 'FL79-1126' strawberry plants. Longevity of
females and numbers of eggs produced per female did not vary among the
cultivars and lines. 'Selva' leaves expressed damage and at lower mite
densities than did any other cultivar or line.

STRAWBERRY CULTURE
E. E. Albregts
Evaluation of Mulch Color for Fruiting Strawberry: During the 1989-90 season,
black polyethylene was mulched over fumigated and fertilized beds. Beds
were then painted with oil base paint in colors of white, yellow, orange,
red, green, brown, blue, or left unpainted. 'Chandler', 'Selva', and Fla.
breeding line 'FL79-1126' were set in all beds. Highest seasonal yields
were obtained from plots mulched with white, yellow, orange and green
mulches. White and yellow mulches resulted in higher average fruit weight
while dark colored mulch resulted in the lowest average fruit weight.
Plots with yellow mulch gave lowest percent marketable fruit because of
more rotten fruit. Soil temperatures at the one and four inch depths in
the plant beds at 2 PM were lowest with the white and yellow mulches.
Early morning soil temperatures were not influenced by mulch color.
Effect of N Source on Strawberry Fruiting Response: During the 1989-90 season,
methylene urea (40% N), sulfur coated urea (37% N), and (NH4)2 S04 coated
with urea formaldehyde (32% N) were applied to plant beds which were
fumigated with methyl bromide and mulched'with black polyethylene.








Fertilizer was applied banded in bed center one to two inches deep at 200
Ibs of N per acre with adequate K, Mg, and micronutrients added. Chandler
and Fla. 79-1126 plants were set in beds. Average fruit weight, percent
marketable fruit, and monthly and seasonal marketable fruit weight were
not different because of fertilizer N source with either clone. Plant size
and foliage color were not different because of N source with either clone.
Foliage samples were taken on 12 December 89, 24 January 90, and 30 March
90, and leaf N content did not vary with either clone at any sampling date
because of N source.

Fertilizing the Summer Strawberry Nursery: Strawberry nursery plants were
fertilized with a 10-10-10 granular fertilizer at least every other week
during the summer to bring the soil soluble salts up to either 0.70, 1.05,
1.40, or 1.75 dS.m-'. Only the 0.70 dS.m-' fertilizer rate was used until
the last of July. Then the other treatments were added. Soluble salts
were determined just prior to and immediately after fertilization.

Dover and Fla. 79-1126 gave the highest plant production during the 1990
season when the soluble salt levels were maintained near the 1.4 dS.m-'
level. Fla. 83-37 gave highest plant production at the 1.4 dS.m-' soluble
salts level, but plant production differences because of fertilizer rate
were small. Fla. 84-1932 did not respond to fertility levels. Keep in
mind that the soluble salt levels were the levels desired, but heavy rains
during the summer kept the average levels to less than half the desired
levels.

Calcium Sprays for Strawberry: During the 1988-89 season, calcium nitrate and
calcium chloride were applied to the foliage of strawberry plants every
two weeks starting on November 29, 1988. Solutions applied contained 480
or 960 ppm calcium. A control, tap water, was also used. Fruit firmness
and resistance to abrasion were not different because of calcium
application. The calcium content of the FL-79-1126 fruit did not vary
because of treatment, but, for Chandler, calcium was highest with the high
rate of calcium chloride and lowest with the high rate of calcium nitrate.
Chandler also had a greater calcium content in the fruit than FL 79-1126.
Since only a few brown and black calyx occurred, no differences because
of calcium treatment occurred. The highest concentration of calcium
chloride spray, 960 ppm, did reduce fruit yield and marketable fruit number
of both clones. This response may have been related to chloride toxicity,
but no foliage burn was noted.

STRAWBERRY DISEASE CONTROL
C. M. Howard

Anthrancose (Black Spot) on Fruit: Field experiments were carried out in the
1988-89 and 1989-90 seasons to evaluate fungicides for control of
anthracnose on 'Pajaro'. In both seasons, the highest yields of marketable
fruit and the lowest percentages of fruit and flowers affected by
anthracnose were obtained from plots treated with Captan twice per week,
with Bravo twice per week until harvest began than Captan twice per week
for the remainder of the season, or with Bravo twice per week all season.
In both seasons, Bravo applied all season gave slightly (but not
statistically significantly) lower marketable yields than the other two








treatments. Treatments with Captan once per week, Thiram twice per week,
or Tersan SP once or twice per week resulted in considerably lower
marketable yields than the above three treatments. In the unsprayed
control plots, 65% and 73% of the fruit and flowers were infected by
anthracnose in the 1988-89 and 1989-90 seasons, respectively. In the
Captan plots, 14% and 17% of the fruit and flowers were infected by
anthracnose in the 1988-89 and 1989-90 seasons, respectively. Bravo
applied all season caused moderate to moderately-severe phytotoxicity
exhibited as blackening of leaves in mid-to late March during both seasons.

Graymold: Field experiments were carried out in the 1988-89 and 1989-90 seasons
to evaluate fungicides for control of graymold on 'Chandler'. The 1988-
89 trial consisted of plots in which twice per week applications of Captan,
Bravo, Ronilan, Rovral, Alliette, and Tersan SP were tested alone and with
a series of plots in which Captan was applied twice per week until graymold
occurred then Captan was applied on Friday each week and Ronilan, Rovral,
or Alliette were applied on Tuesday each week. All treatments resulted
in higher marketable yields of fruit than the unsprayed control. The
Captan-Ronilan treatment gave the highest marketable yield even though,
statistically, control of graymold was not significantly better than the
unsprayed control.

In the 1989-90 trial, the treatments Captan twice per week, Bravo twice
per week until harvest began then Captan twice per week for the remainder
of the season, and Bravo twice per week resulted in the highest marketable
yields. Treatments of Thiram twice per week or Captan once per week
resulted in higher yields than the unsprayed control but lower yields than
those from the first three treatments. All treatments gave significant
control of graymold and fruit anthracnose. Slight phytotoxicity, exhibited
as slight blackening of older leaves, occurred on March 20, 1990 in all
plots that received Bravo for the entire season.

Anthracnose: Crown to Crown Spread: Field experiments were performed in the
1988-89 and 1989-90 seasons to determine if spread of anthracnose crown
rot may occur in the fruit production field and to determine the ability
of the three pathogens to cause crown rot and death of plants. Plants were
set at 2 (2 plants per hole), 6, and 12 inch spacings. Alternate plants
(1 plant per hole in the 2 inch spacing) were inoculated with
Colletotrichum in early December. All three species of Colletotrichum that
cause strawberry anthracnose were used in different series of plots. The
tests were performed on 'Chandler' the first season and on 'Chandler' and
'Pajaro' the second season.

Colletotrichum acutatum which usually does not cause crown rot and wilt
failed to kill any inoculated plants by mid April either year.
Colletotrichum fragariae and Glomerella cinqulata, both of which cause
crown rot and wilt, killed most inoculated plants within 7 weeks. Some
of the noninoculated 'Chandler' plants in plots with C. fragariae and G.
cinqulata died by mid April. At the 2 and 12 inch spacing 60% and 8%
respectively, of the noninoculated 'Pajaro' plants died by mid April. Only
a few noninoculated plants of either cultivar at any spacing died before
April.








These results indicate that spread of anthracnose crown rot can occur in
the fruit production field but that such spread probably would be slight
at normal plant spacing.

Inoculation of Roots with Anthracnose Pathogens: This experiment was performed
to determine if root infection by the anthracnose pathogens could spread
up into the crowns and cause wilting of plants. Injured and noninjured
roots of potted 'Chandler' and 'Pajaro' plants were inoculated with spore
suspensions and with pieces of roots infected by each of the three
anthracnose pathogens. Only a few plants died during the five months this
trial was in progress. There were more noninoculated control plants that
died than inoculated plants. These results indicate that possible soil
borne spores or small amounts of infected debris in the soil are not likely
to result in the development of anthracnose crown rot and death of plants.

Anthracnose in the Nursery: This experiment was performed to evaluate Captan
and Bravo for phytotoxicity and for control of anthracnose and leaf blight
in the summer nursery and to obtain data in support of possible
registration of Bravo on strawberries. Bravo at 1.5 pts per acre applied
2 or 3 times per week gave the best control of anthracnose although
statistically control was not better than that resulting from Captan
applied 2 or 3 times per week. Bravo at 2 or 2.5 pints per acre twice per
week gave less control. Captan 3 times per week gave the best control of
leaf blight. Bravo caused mild burn of mature leaves after an application
in mid August. Even though applications continued through mid September,
burn did not increase.

Anthracnose: Crown to Crown Spread: These experiments were performed in the
greenhouse during the 1988-89 and 1989-90 seasons in conjunction with the
field experiments to determine if the anthracnose pathogens can spread from
infected to noninfected crowns and to determine the ability of the three
anthracnose pathogens to cause anthracnose crown rot. Plants were set two
per pot with the crowns in contact or 2 inches apart. Spores of the
pathogens were injected into the crown of one plant in each pot and the
plants were observed for four and a half months. 'Chandler' and 'Pajaro'
were used the first season. Only 'Chandler' was used the second season.

Only one plant injected with C. acutatum during the two seasons died. Most
of the plants injected with C. fraqariae or G. cinqulata died within 5
weeks. During the two seasons only 2 of 120 noninoculated plants growing
2 inches from crown rot infected plants died. In pots in which crowns were
in contact, there appeared to be some spread of G. cinqulata to the
noninoculated plant especially with 'Pajaro'. Colletotrichum fraqariae
did not spread to the noninoculated plants.

STRAWBERRY BREEDING PROGRAM
C. K. Chandler

Cultivar Development: FL 79-1126 received mixed reviews in limited west central
Florida grower trials. Albinism, necrotic calyxes, and hollow tips were
observed on fruit from several pickings during the 1989-90 season. FL 83-
37 plants propagated in Canada in 1989 had high early yield, high total
yield, were easy to harvest, and had relatively uniform fruit size and








shape. Unfortunately, the fruit were only medium firm with a short shelf
life, based on cold storage tests conducted at the USDA-ARS lab in Orlando.
FL 85-4925, a selection with the same parentage as FL 83-37, produces
firmer fruit than FL 83-37, and may prove to be a more useful clone than
FL 83-37. Canadian plants of 85-4925 are currently being evaluated in
trials at AREC-Dover. Three relatively new selections, FL 87-25, FL 87-
210, and FL 87-278 produced attractive fruit during the 1989-90 season,
and are currently being evaluated in a replicated trial at AREC-Dover.
In addition to the above mentioned clones, approximately 75 selections were
propagated during the summer of 1990 and will be observed during the 1990-
91 season.

Anthracnose Resistance: A multiyear study is being conducted to elucidate the
inheritance patterns of resistance to anthracnose crown rot. A preliminary
evaluation of the data collected to date indicates that
resistance/susceptibility may be at least partially controlled by a major
gene.

Propagation Study: In a 2-year study (1988-90), Canadian propagated plants of
3 University of Florida selections started producing ripe fruit 2 to 3
weeks before Florida propagated plants.

Stability Study: An analysis of 2 cultivars ('Selva' and 'Pajaro') and 3
University of Florida selections over 5 seasons showed that none of the
clones had consistently high marketable yield, and only 1 clone, FL 81-
1350, had relatively large and stable fruit size.

Variance Components Study: A study was conducted (1987-90) to derive estimates
of genetic and environmental variability for fruit yield, size, and
firmness. Results from this study will be used to design a sampling scheme
for obtaining specific levels of genetic discrimination.

WATER MANAGEMENT FOR STRAWBERRY PRODUCTION
C.D. Stanley and G.A. Clark

Strawberry water management research at AREC-Dover is primarily directed at
investigating management practices which will result in information useful for
making water management decisions, ultimately achieving a higher efficiency of
agricultural water use and prudent use and protection of a vital natural
resource. The following describe current and recent past research designed to
meet these objectives.

The Use of Runoff Recovery Systems for Reducing Groundwater Withdrawal: A long-
term study investigating the pros and cons of using runoff recovery systems
to ultimately reduce groundwater withdrawals has been recently completed.
The objectives of the project were to determine reductions in groundwater
use which result with the use of the system, to identify modifications in
current management practices which are caused by using the system, to
develop a computer model to predict recovery pond behavior under various
conditions, and to develop recovery pond design criteria and guidelines
to aid in determining feasibility and behavior in a new site installation.
Results from this project showed a reduction in average groundwater
withdrawals of 63% (ranging from 52 to 70%) with use of this system during








the 1985-89 growing seasons. These reductions were dependent on rainfall,
growing conditions, and especially, cold protection events. The amount
of water applied to the field wasn't reduced, only the amount withdrawn
from groundwater. It was found critical to have a proper design to ensure
adequate water storage during cold protection events. A significant
relationship between hours of pumping for cold protection and the % of
applied water recovered, resulting in prediction capability for expected
return flow during those events. Management of the water level in the
recovery pond was found to have a significant effect on the degree of
success with the system.

Water Requirements and Crop Coefficients of Strawberries: A multi-year study
using in-field lysimeters is being conducted to determine the water
requirements of fruiting strawberry production needed to meet evaporative
demand in different periods of the growing season. The lysimeters allow
determination of strawberry water use by tracking the water inputs and
outputs (irrigation and drainage), thus resulting the actual crop water
use. Since water requirements change as the plant canopy and environmental
conditions change, the water use measurements are compared to pan
evaporation and other weather conditions to develop crop coefficients
useful in improving irrigation scheduling. Results to date show that
strawberry crop water requirements increase from <0.1 inches/month early
in the season to 3-4 inches/month late in the season, with an overall
seasonal use of 8-10 inches. Actual water requirements are higher due to
system inefficiencies.

Using Tensiometers to Schedule Water Applications for Microirrigated
Strawberries: Tensiometers are valuable tools for providing a measurement
of the soil moisture conditions in a production bed. Efficient
microirrigation management involves applying water to the root zone and
minimizing the movement of water and nutrients beyond the root zone. The
tensiometer can provide information that improves irrigation scheduling
so that adequate applications are made without losses. The objectives of
this study are to evaluate the effect of soil moisture levels on optimum
strawberry production. The experiment uses three tensiometer threshold
level treatments [5, 10 and 15 centibars (cb)] causing three different soil
moisture levels to occur in the field. The tensiometers are fitted with
magnetic switches which, when checked by the computer, cause irrigation
to occur when needed to maintain the desired threshold level. Initial
1989-90 results showed that, as expected, applications increased with
treatments calling for higher soil moisture levels, but unexpectedly, that
yield or fruit size was not affected by irrigation amounts. Seasonal
application amounts were 6 to 7.5 inches for the 15 and 10 cb treatments,
but additional data are needed.

WEED CONTROL
J. P. Gilreath

Herbicide research on strawberries has been restricted by the scarcity of new
products to evaluate and manufacturer lack of support for registration.
Several herbicides previously pursued through the federal IR-4 program by








Florida have been removed from the program due to the manufacturer
withdrawing their support for registration. It is not anticipated that
this situation will change in the near future.

Favorable label changes which have occurred are the change in preharvest
interval (PHI) for Gramoxone Extra (formerly sold as Gramoxone Super) to
three days and the registration of Enquik for postemergence control of
broadleaf weeds in strawberry middles. Gramoxone Extra is a new
formulation of paraquat which contains 2.5 Ibs. of paraquat cation per
gallon instead of 1.5 Ibs as contained in Gramoxone Super. No more than
three applications per season are allowed and no application can be made
within three days of harvest. Enquik can be applied at label rates for
control of broadleaf weeds; grasses are not controlled by Enquik alone.
This should provide the grower some flexibility during the colder months
when grasses are not a problem and winter annuals are troublesome. When
grasses are a problem, Poast may be used for postemergence control provided
the grass is not too large and the label is followed, particularly with
regard to the use of crop oil concentrate.

The only change from previous recommendations for preemergence herbicides
is the loss of Enide as a registered product, thus leaving growers with
a choice between Dacthal and Devrinol.

LABELED HERBICIDES FOR STRAWBERRIES

Rate
Herbicide Ibs ai/A production rate Application method

Dacthal* 9.0 12 Ibs/A Post-transplant,
preemergence

Devrinol* 2.0 to 4.0 4 to 8 Ibs/A Post-transplant,
preemergence

Enquik** N/A 5 to 10 gal/A Postemergence

Gramoxone Extra*** 0.47 1 1/2 pt./A Postemergence,
directed,
shielded

Poast**** 0.28 to 0.375 1 1/2 to 2 pt./A Postemergence

*Do not apply from bloom through harvest.
**Controls broadleaf weeds only. Use flat fan or hollow nozzles; 40 psi
minimum pressure, 20 to 50 gal/acre spray volume, 6:1 or lower water to
Enquik volume dilution ratio. No preharvest interval.
***Maximum of 3 applications, no applications closer than 3 days pre-harvest
(3 day PAI).
****Controls grasses only. Always use with 2 pts. of crop oil concentrate per
acre. Do not apply within 30 days of harvest.








NEMATODE MANAGEMENT FOR STRAWBERRY
A. J. Overman

The sting nematode (Belonolaimus) and the root-knot nematode (Meloidogyne) are
primary pathogens of strawberry. High populations of either nematode in
the soil at planting can result in crop failure: preplant fumigation
reduces the populations and protects the plant roots.

The crop profits from the soil fumigant in the warm weather following
planting and further benefits from the cooler months which follow because
recovery of the nematode populations is slow in cooler weather.

When rainfall is below normal during the summer and early fall, preparation
for soil fumigation is imperative. Moisture in the fields must be
maintained to rot plant debris, germinate weed seed and fungi, and hatch
nematode eggs in order to obtain maximum results with the rate of fumigant
found on the label. In dry seasons, fumigants can fail if proper
precautions are not taken.

Strawberry crops are generally protected even longer into the season by
the cool weather which occurs 6 weeks or so after planting. When the fall
and winter temperatures are above average, nematode populations may attain
damaging levels causing plants to senesce prematurely. Therefore, special
care should be paid to field preparation and proper procedures for soil
fumigation in these drought years.


















STRAWBERRY FIELD TOUR








Optimal Period of Release of Predatory Mites


J.F. Price and M. van de Vrie


Location:

Objectives:


Field Set:

Treatments:


Block B


To determine which point in the build-up of twospotted spider
in strawberry is best for release of the predatory
Phvtoseiulus persimilis, to effect spider mite control.


October 26

Predator releases made on:
1. Week 1
2. Week 3
3. Week 5
4. Week 7
5. (No releases)
6. (No releases, Kelthane weekly)


Operation:


Summary:


Weeks 1 and 2
Weeks 3 and 4
Weeks 5 and 6
Weeks 7 and 8
(No releases)
(No releases,


Kelthane weekly)


All plants were infested with twospotted spider mite on January
7. Week 1 release of predators occurred on 10 January.

Work in progress.


Interactions Between Spider Mites and Strawberry Lines and Cultivars

J.F. Price, M. van de Vrie and C.K. Chandler


Location:

Objectives:


Block E


To determine effects of seven strawberry
cultivars on twospotted spider mite longevity
on the effects of twospotted spider mites on
breeding lines and cultivars.


breeding lines and
and reproduction and
leaves of the seven


Field Set:

Treatments:


October 26


Seven strawberry
1. 'Selva'
2. 'Pajaro'
3. 'Dover
4. 'Chandler'
5. 'FL83-37'
6. 'FL85-4925'
7. 'FL87-278'


breeding lines and cultivars:


mites
mite,








Operations:





Summary:


Leaves from plants with fruit and from plants with flowers removed
(simulating aspects of a vegetative plant) as they appeared will
be taken to the laboratory where female twospotted spider mites
will be placed on them. The longevity of the spider mites and
number of eggs produced will be measured. Effects of feeding by
the mites on the leaves will be measured.

Work in progress.


Demonstration of Biological Control of Twospotted Spider Mite
at AREC-Dover

J.F. Price and M. van de Vrie


Location:

Objectives:


Treatment:

Operations:



Summary:


Entire Dover AREC Center

Establish twospotted spider mite control on the AREC Dover Center
using Phvtoseiulus persimilis predatory mite and minimum
insecticides and miticides as may be necessary.

Phvtoseiulus persimilis predators released throughout most of the
center three times at weekly intervals beginning January 10.

Plants will be scouted throughout the center each week. Selected
"hot spots" may be treated with miticides or may be left without
miticidal treatment. Least disruptive pesticides will be applied
as prudent.

Work in progress.


Delaying Fertilization of Fruiting Strawberry

E.E. Albregts


Location:


Block G


Objective:

Clones:

Treatments:


Operation:


To evaluate the effect of delayed fertilization on the fruit
quality, timing, and volume of fruit yields.

Each plot has FL-79-1126 on south and Selva on the north.
Transplanted on October 18, 1990.


Plot No.
1
2
3
4


Time of fertilization
At bedding
End of establishment
2 weeks after establishment
4 weeks after establishment


A 15.6-2.0-13.0 (NPK) fertilizer with magnesium and micronutrients
was applied at 1280 Ibs/acre and banded in bed center one to two
inches deep. Plant growth and foliage color will be monitored
periodically and fruit yield and quality data will be obtained.








Summary:


Location:

Objective:


During the 1989-90 season, foliage color was lighter through
December with treatments 3 and 4. Early yields and total yields
of Selva were reduced when fertilization delayed. Treatment 4 with
FL-79-1126 had reduced early yields.


Nitrogen Rate on Fruit Yield and Quality of Strawberry

E.E. Albregts and C.K. Chandler


Block G


Evaluate the effect of a wide range of nitrogen fertilization on
fruit quality and yield.


Selva (Canada), FL-79-1126,
Transplanted on October 18, 1990.


and FL-83-37


(AREC-Dover).


Treatments:







Operation:



Summary:


N-Rate


Clone


Ibs/acre Selva FL-79-1126 FL-83-37
---------------P-- lot No.------------------

50 1 4 7
200 2 5 8
400 3 6 9


Nitrogen plus potassium, phosphorus, magnesium and micronutrients
were applied one-fourth broadcast and three-fourths banded in bed
center one to two inches deep. Plant size and color periodically
evaluated. Fruit yield and quality recorded at harvest.

For the 1989-90 trial, the 200 Ibs/acre rate of nitrogen gave
highest yield while the 400 Ibs/acre rate gave the lowest yield.
The highest N rate also gave lower percent marketable fruit, lowest
average fruit weight, and more rotten fruit.


Response of Strawberry to Mulch Color

E.E. Albregts


Location:

Objective:

Clones:


Treatments:


Block G


To evaluate the effect of various mulch colors on plant growth and
fruit yield and quality.

Selva is on the south end of each plot and Chandler is on the north
end and FL-79-1126 is between these two clones; transplanted on
October 19, 1990.

Mulch colors are black, blue, brown, green, red, orange, yellow,
and white.


Clones:








Operation:






Summary:


Black polyethylene was painted with various colors of water-based
paints prior to planting. A 15.6-2.0-13.0 (NPK) fertilizer with
magnesium and micronutrients was applied at 1280 Ibs/acre with one-
fourth broadcast and remainder banded 1 to 2 inches deep in bed
center. Plant growth and foliage color will be monitored
periodically as will N and K content of foliage. Fruit yield and
quality data will be taken at harvest.

Light color mulches gave higher yields than the darker mulches
during the 1989-90 season.


Strawberry Fruiting Response to Foliage Removal

E.E. Albregts


Location:

Objective:

Clones:


Treatments:


Operation:

Summary:


Block G


To evaluate the effect of various amounts of foliage removal on
plant growth and fruiting response.

Selva, Chandler, and Pajaro were grown in Canadian nurseries and
Dover, and FL 79-1126 were grown at AREC-Dover. Transplanted on
October 22, 1990.


Foliage


Strawberry Clone


Remaining* Selva Chandler Pajaro Dover 79-1126
------------------Plot No.-----------------

Control 1 4 7 10 14
1 inch 2 5 8 11 15
3 inch 3 6 9 12 16
5 inch 13 17

*Amount of foliage in inches remaining above crown.

At transplanting, all clones had a control (no foliage removed)
and foliage removed to one and three inches above crown. Dover
and FL 79-1126 foliage was also removed to five inches above crown.

Standard fertilizer, pesticide, and harvest schedules were used.

During the past two seasons, defoliation of local or Canadian grown
plants at transplanting or at 2 weeks before transplanting reduced
early and total yields as well as average fruit weight.








Preplant Chilling and Planting Date for Strawberry


E.E. Albregts


Block G


Objective:


Clones:


Treatments:


Operation:


Evaluate container plants for the effect of planting date and
chilling on their fruiting and growth response.

Dover and FL-79-1126 with planting dates of A = October 1, B =
October 15, and C = October 29, 1990.

Planting Date Chilling Dover FL-79-1126
------Plot No.------

A Yes 1 7
A No 2 8
B Yes 3 9
B No 4 10
C Yes 5 11
C No 6 12


After two weeks to establish transplants in container trays, plants
were then placed in a cooler at 38F for 13 days from 5 PM to 8 AM
daily. When chilling period was over, all plants remained in
containers and were grown in direct sunlight for one more week before
being transplanted into the field. Normal harvest procedures and
pesticide applications were given in the field. Fruit were harvested
twice weekly, graded for quality and size, and weighed.


Summary: Minimal irrigation was required to establish. Yield data are being
collected.

Inoculation of Strawberry Buds with Anthracnose

C.M. Howard


Location:

Objectives:



Treatments:


Block C


To determine if any of the three anthracnose pathogens will cause
infection of bud leaves or anthracnose crown rot when spores are
dropped into the control buds in the fruiting field and to
determine if infection may spread to the noninoculated plants.

X. Plants inoculated 10-27-90 and irrigation for establishment
continued for 7 days.
Y. Plants inoculated 11-8-90 after irrigation for establishment
discontinued.


noninoculated control
Colletotrichum fraqariae


Location:








Glomerella cinqulata
Colletotrichum acutatum


Operation:


Cultivar: Chandler
Set: 10-24-90
Plants spaced 2 (2 plants/hole), 6, and 12 inches apart for
each treatment.


Crown to Crown Spread of Anthracnose Crown Rot

C.M. Howard


Location:

Objective:


Block C


To compare the ability of the three anthracnose pathogens to cause
crown rot when spores are injected into crowns in the fruiting
field and to determine if the pathogens will spread from inoculated
to noninoculated plants at various spacings.


Treatments:


noninoculated control
Colletotrichum acutatum
Colletotrichum fraqariae
Glomerella cinqulata


= 2 inch spacing
= 6 inch spacing
= 12 inch spacing


Operation:


1. Cultivar: Chandler
2. Set: 10-24-90
3. Plants set at 2 (2 plants per hole), 6, and 12 inch
spacings.
4. Plants inoculated 12- -90


Control of Powdery Mildew

C.M. Howard


Location:

Objective:

Treatments:


Block C


To evaluate fungicides for control of powdery mildew and for
phytotoxicity.

Fungicides, rate per acre, and interval


Unsprayed control
Nova 1.25 oz, 2 weeks
Nova 2.5 oz, 2 weeks
Nova 5.0 oz, 2 weeks
Benlate 1 lb, 1 week
Sulfur 4 Ibs, 1 week
Bayleton 2 oz, 1 week
Bayleton 4 oz, 3 weeks
Fermenta ASC 66811 9 oz, 1 week
Fermenta ASC 66811 18 oz, 2 weeks








Operation:


1. Cultivar: Selva
2. Set: 10-15-90


Control of Gray Mold

C.M. Howard


Location:

Objective:


Treatments:


Operation:


Block C


To evaluate fungicides
phytotoxicity.


for control


of gray mold


and for


Fungicides; rate per acre; and number of applications per week.

1. Unsprayed control
2. Captan; 6 Ibs, 2
3. Captan; 6 Ibs, 2 until gray mold occurs then Captan;
6 Ibs, 2 + Ronilan; 2 Ibs, 1
4. Captan; 6 Ibs, 2 until gray mold occurs then Captan;
6 Ibs, 2 + ASC 66825; 1 Ib, 1
5. Captan; 6 Ibs, 2 until gray mold occurs then Captan;
6 Ibs, 2 + Fermenta ASC 66825; 1.5 Ibs, 1


Cultivar: Chandler
Set: 10-24-90


Control of Powdery Mildew with Nova (Rally)

C.M. Howard


Location:

Objective:


Treatments:



Operation:


Comments:


Block F


To evaluate
control and
analysis.


Nova applied at 2 week intervals for powdery mildew
phytotoxicity and to obtain samples for residue


1. Unsprayed control
2. Nova 1.25 oz per acre
3. Nova 2.5 oz per acre
4. Nova 5 oz per acre

1. Cultivar: Selva
2. Set: 10-15-90
3. Six applications beginning 10-30-90 and ending 1-8-91

The incidence of powdery mildew remained low in the control plot
until early December after which it reached moderate to moderately
severe levels in the control. By this time, Nova had been applied
three times to the proper plots. At this time, the 1.25 oz rate
was giving good control and the two higher rates were giving
excellent control.








Variety Trial


C.K. Chandler and E.E. Albregts


Location:

Objective:




Operation:



Entries:



Clone


Block B


1) To obtain unbiased comparisons between new and standard
cultivars and promising selections from the IFAS strawberry
breeding program, and 2) to determine the influence of propagation
site (northern vs. southern latitude) and planting date on the
performance of selected clones.

A select group of clones, propagated in either northern or southern
latitude nurseries or both, were planted on one or more dates in
October.

Clones are listed below in alphabetical order. Plot numbers (in
parenthesis) are in columns corresponding to the time of month in
which they were planted (either early, mid, or late October).

Planting Date in October


Source


Early Mid Late
------------------Plot No.------------------


Dover
Dover
Dover


Grace
Grace
Oso Grande
Pajaro
Seascape
Selva
FL 79-1126
FL 79-1126
FL 79-1126


82-1452
82-1452
83-37
85-4925
85-4925
87-25
87-67
87-210
87-212
87-213
87-236
87-278
87-282
87-314


Florida
Northern Quebec
Southern Quebec


Tennessee
Tennessee
Ontario
Ontario
California
Ontario
Florida
Northern Q
Southern Q


(bare root)
(plugs)
5'


2
3:
uebec 9
uebec 1


Florida
Northern Quebec
Florida
Florida
Nova Scotia
Florida
Florida
Florida
Florida
Florida
Florida
Florida
Florida
Florida


3,58,107
4,56,128
6,37,61,85,
15,127


0,75,147


8,67,132
3,92,112
,53,148
1,27,52,55,
09,146

,94,141

9,78,142

8,57,140

0,84,117


4,62,133
9,74,119


3,76,145
45,72,113
18,79,104

35,89,124
46,68,131
16,91,143


43,82,137
8,71,149
5,98,130
22,63,101

30,83,126
39,97,121
41,100,136
21,64,134

20,69,118
13,81,111
2,59,125
4,86,138
17,93,135
49,96,122
12,60,114
44,80,102
7,70,123


25,77,116





26,95,103
42,51,150






40,66,120
48,99,139
32,87,108
14,88,110

47,65,144


31,73,105
1,90,129


Clone Source








Observational Trial


C.K. Chandler


Location:

Objective:

Operation:


Block B


To identify clones that tend to maintain desirable plant and fruit
characteristics throughout the season.

Ten or twenty plants each of approximately 75 clones were planted
on October 17. Ripe fruit are harvested twice weekly, and the
volume of fruit harvested is recorded. Harvested fruit are rated
for appearance, and notes are taken periodically on clones with
desirable plant habits and attractive fruit.


Row Trial

C.K. Chandler


Location:

Objective:



Operation:


Block B


To provide a demonstration area to observe standard cultivars and
promising selections. This trial is also used to assess the
harvest efficiency of promising selections, and to provide a source
of fruit for postharvest studies.

One or two rows each of 'Selva', 'Oso Grande', and several
promising selections were planted on October 12 or 19. The volume
of ripe fruit harvested from each row is recorded.


Seedling Trial

C.K. Chandler


Location:

Objective:

Operation:


Blocks B and H

To select seedlings with large, attractive, and firm fruit.

Two to four plants each of about 3,000 seedlings were planted
during the period October 15-23. The plants are observed weekly,
and those showing the desired characteristics are flagged.


Water Requirements and Crop Coefficients of Strawberries

G.A. Clark, E.E. Albregts, C.D. Stanley,
A.G. Smajstrla, and F.S. Zazueta


Location:

Objectives:


Block A


1) To determine the necessary water requirements of fruiting
strawberries to meet evaporative demands, and 2) To determine the








ratio of plant water use to evaporative demand for use as a within
season aid to schedule irrigations.

Crop: Pajaro on south end and 79-1126 on north end of each plot.

Transplanted: October 27, 1990


Operation:





Summary:


Lysimeters are used which allow accurate accounting of water inputs
to and outputs from the strawberry plant and soil system. Measured
amounts of water are applied by drip irrigation, then water
drainage through the soil profile is measured to determine the
plant water requirements. Pan evaporation and other weather
conditions are measured to determine evaporative demand.

This study is currently in the third and last year of the project.
Preliminary results indicate initial strawberry water requirements
at 0.05 to 0.10 inches per month increasing to 1.0 to 1.5 inches
per month during mid season and up to 3.0 to 4.0 inches per month
during the peak growth and production periods. Seasonal water
requirements to meet evaporative demands may average 8 to 10
inches. Actual water requirements will be higher to accommodate
irrigation system inefficiencies. A final report with all results
and recommendations will be available in the spring of 1992.


Tensiometer Schedule, Drip Irrigated Strawberries

G.A. Clark, E.E. Albregts, C.D. Stanley, A.G. Smajstrla,
and F.S. Zazueta


Location:

Objective:


Crop:


Block A


To evaluate the effects of irrigations scheduled at different soil
water tension thresholds on seasonal yield and water use.


Strawberry, 79-1126


Transplanted: October 27, 1990


Treatments:

Plot Layout:


Tensiometer thresholds of 5 cb; 10 cb; 15 cb


Treatment
5 cb
10 cb
15 cb


Plot No.'s
4, 5, 9, 12
1, 6, 7, 8
2, 3, 10, 11


Plot Diagram
2 1 N
4 3
6 5 -- > E
8 7
10 9
12 11


Operation:


Treatments of irrigation management used tensiometers placed at
6 inch depths to monitor soil water tension. The tensiometer
levels represented conditions which ranged from wet toward dry.
Sprinkler irrigation was used for establishment, applying 0.20








in/hr from 1000 hrs until 1700 hrs every day during a
establishment period. Subsequent irrigation was by
irrigation system on a daily basis. Drip irrigation was
apply 0.04 inch per cycle. Additional daily cycles were
irrigation requirements increased.


two week
the drip
timed to
added as


Irrigation application increased with decreasing soil water tension
management levels. However, neither marketable yield nor average
fruit size were different as a function of irrigation treatment.
Strawberry plant water applications averaged 13 percent of pan
evaporation during November and December, increasing to 40 percent
of pan during January and February, and to 43 to 55 percent of pan
during March and April. Seasonal evapotranspiration irrigation
applications for the 10 and 15 cb tensiometer management levels
ranged from 6 to 7.5 inches.


N and K Rates for Microirrigated Strawberry

E.E. Albregts, G.A. Clark, and C.D. Stanley


Location:

Objective:


Clones:


Block A


To evaluate the N and K rates with microirrigation on strawberry
growth and fruiting response.


FL 79-1126 north end (local) and Selva south end
Transplanted October 18, 1990.


(Canada).


Treatments:


Oper tion:






Summary:


Plot Planting to
Nn Fctahlishment


Establishment 1st Flower-
o t 1 st fl ower to fruiting Fruiting


----------(lbs N & K20/day by microirrigation)---------

1 0 1.0 1.0 1.0
2 1.0 1.0 1.0 1.0
3 0.5 0.5 0.75 0.75
4 0.75 0.75 1.0 1.0
5 1.0 1.0 1.5 1.5

Phosphorus, magnesium, and micronutrients were broadcast at
bedding. All N and K applied through microirrigation at rates
shown above. Plant growth and foliage color will be monitored
periodically as well as the N and K content of foliage. Fruit
yield and quality data will be taken at harvest. T-tape
microirrigation tubing with emitter spacing of 8 inches and a
discharge rate of 25 gallons/hr/100 ft.

The lack of N and K fertilizer applied through the irrigation line
during establishment did not reduce plant growth.


Summary:








Preplant N and K for Microirrigated Strawberry

E.E. Albregts, G.A. Clark, and C.D. Stanley


Location:

Objective:


Block A


To determine if microirrigated strawberry respond to rate or method
of application of preplant N and K.


Each plot has 'Pajaro' on south end
Transplanted on October 25, 1990.


and FL 79-1126 on north end.


Treatments:







Operation:







Summary:


Fertilizer
Plot No. Preplant Fertilizer Application Method

1 Control
2 20 Ibs N & K20 per acre Broadcast
3 40 Ibs N & K20 per acre Broadcast
4 20 Ibs N & K20 per acre Band
5 40 Ibs N & K20 per acre Band

Preplant N and K20 were applied in a band above the
microirrigation tube. Liquid N and K20 applied by microirrigation
at 1 Ib/acre/day starting on October 26, 1990.

Phosphorus, magnesium, and micronutrients were broadcast prior to
bedding. Plant growth and foliage color will be monitored
periodically as will N and K content of foliage. Fruit yield and
quality data will be taken at harvests.

Previous research the last 2 years indicated that preplant
fertilization not needed if fertilization through microirrigation
was initiated within a few days of transplanting.


Clones:








ACKNOWLEDGEMENT OF INDUSTRY FOR THE RESEARCH PROGRAMS
AT THE AGRICULTURAL RESEARCH AND EDUCATION CENTER,
DOVER, FLORIDA


The effectiveness of the research programs at the Agricultural Research and
Education Center here in Dover has been greatly enhanced by the excellent
support from the various segments of the Agri-business industries and producers,
both locally and nationally. This support in the form of financial grants-in-
aid, supplies, services, or equipment, supplements existing state funds and
makes each research project at the Center far more productive than could be
realized otherwise. We sincerely appreciate your participation in these
research programs and are pleased to acknowledge your support.

Listed below are the names of agencies, firms or individuals who have
contributed significantly to the research programs during the past two years.
We trust that our records are complete and say again, "Thank you for your
confidence".


Chemical Dynamics, Inc.
Fermenta Plant Protection
Florida Foundation Seed Producers
Florida Strawberry Growers Association, Inc.
Kay Mukai Research Foundation
Southwest Florida Water Management District
Uni-Royal Chemical
Nor-Am Chemical Company
CIL-Inc.
H. Ghesquiere Farms, Inc.
Pursell Industries
Rhone
Monsanto
Hi Yield Bromine


Plant City, FL
Albany, GA
Greenwood, FL
Plant City, FL
Watsonville, CA
Brooksville, FL
Raleigh, NC
Marietta, GA
London, Canada
Simcoe, Canada
Sylacauga, AL
Longwood, FL
St. Louis, MO
Plant City, FL























To 574
Gallagher Rd


Moore Lake Rd


To 574
& Dover


To 574


Branch Forbes Rd


1-75




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