Group Title: Bulletin - University of Florida. Agricultural Experiment Station ; 204
Title: Strawberries in Florida
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00026390/00001
 Material Information
Title: Strawberries in Florida culture, diseases and insects
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: p. 477-523 : ill. ; 23 cm.
Language: English
Creator: Brooks, A. N ( Albert Nelson )
Watson, J. R ( Joseph Ralph ), 1874-1946
Mowry, Harold
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1929
 Subjects
Subject: Strawberries -- Florida   ( lcsh )
Strawberries -- Diseases and pests -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by A.N. Brooks, J.R. Watson and Harold Mowry.
General Note: Cover title.
 Record Information
Bibliographic ID: UF00026390
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000923511
oclc - 18173868
notis - AEN4062
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Other version: Alternate version (PALMM)
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HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida







Bulletin 204


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
Wilmon Newell, Director






STRAWBERRIES IN FLORIDA

CULTURE, DISEASES AND INSECTS

By

A. N. BROOKS, J. R. WATSON AND HAROLD MOWRY


Fig. 125.-The double row system of planting strawberries.


Bulletins will be sent free upon application to the
Agricultural Experiment Station
GAINESVILLE, FLORIDA


May, 1929








BOARD OF CONTROL


P. K. YONGE, Chairman, Pensacola
E. W. LANE, Jacksonville
A. H. BLENDING, Leesburg
W. B. DAVIS, Perry


FRANK J. WIDEMAN, W. Palm Beach
J. T. DIAMOND, Secretary, Talla-
hassee.
J. G. KELLUM, Auditor, Tallahassee


STATION EXECUTIVE STAFF


JOHN J. TIGERT, M.A..LL.D., President
WILMON NEWELL, D. Sc., Director
S. T. FLEMING, A.B., Asst. Director
J. FRANCIS COOPER, B. S. A., Editor
ERNEST G. MOORE, M. S., Asst. Ed


IDA KEELING CRESAP, Librarian
RUBY NEWHALL, Secretary
K. H. GRAHAM, Business Manager
RACHEL MCQUARRIE, Accountant


MAIN STATION-DEPARTMENTS AND INVESTIGATORS


AGRONOMY
W. E. STOKES, M. S. Agronomist
W. A. LEUKEL, Ph. D., Asso.
C. R. ENLOW, M. S. A., Asst.*
FRED H. HULL, M. S. A., Asst.
ANIMAL HUSBANDRY
A. L. SHEALY, D.V.M., Veterinarian,
in Charge
D. A. SANDERS, D.V.M., Asst. Vet.
E. F. THOMAS, D.V.M., Asst. Vet.
R. B. BECKER, Ph.D., Asso. in Dairy
Husbandry
C. R. DAWSON, B. S. A., Asst. Dairy
Investigations
CHEMISTRY
R. W. RUPRECHT, Ph.D., Chemist
R. M. BARNETTE, Ph. D., Asso.
C. E. BELL, M. S., Asst.
H. L. MARSHALL, M. S., Asst.
J. M. COLEMAN, B. S., Asst.
J. B. HESTER, B. S., Asst.
COTTON INVESTIGATIONS
W. A. CARVER, Ph. D., Asst.
M. N. WALKER, Ph. D., Asst.
E. F. GROSSMAN, M. A., Asst.
RAYMOND CROWN, B.S.A., Field Asst.


ECONOMICS, AGRICULTURAL
C. V. NOBLE, Ph. D., Ag. Economist
BRUCE MCKINLEY, A.B., B.S.A., Asst.
M. A. BROKER, M. S. A., Asst.
R. H. HOWARD, B.S.A., Field Asst.
ECONOMICS, HOME
OUIDA DAVIS ABBOTT, Ph. D.. Chief
L. W. GADDUM, Ph. D., Asst.
C. F. AHMANN, Ph. D., Asst.
ENTOMOLOGY
J. R. WATSON, A. M., Entomologist
A. N. TISSOT, M. S., Asst.
H. E. BRATLEY, M. S. A., Asst.
HORTICULTURE
A. F. CAMP, Ph. D., Horticulturist
M. R. ENSIGN, M. S., Asst,
HAROLD MOWRY, Asst.
G. H. BLACKMON, M. S. A., Pecan
Culturist
PLANT PATHOLOGY
W. B. TISDALE, Ph. D., Plant Path.
G. F. WEBER, Ph. D., Asso.
A. H. EDDINS, Ph. D., Asst.
K. W. LOUCKS, B. S., Asst.
ERDMAN WEST, B. S., Mycologist


BRANCH STATION AND FIELD WORKERS
Ross F. WADKINS, M. S., Lab. Asst. in Plant Pathology (Quincy)
JESSE REEVES, Foreman, Tobacco Experiment Station (Quincy)
J. H. JEFFERIES, Superintendent, Citrus Experiment Station (Lake Alfred)
W. A. KUNTZ, A. M., Assistant Plant Pathologist (Lake Alfred)
J. FRANKLIN FUDGE, Ph. D., Assistant Chemist (Lake Alfred)
GEO. E. TEDDER, Foreman, Everglades Experiment Station (Belle Glade)
R. V. ALLISON, Ph. D., Soils Specialist (Belle Glade)
L. O. GRATZ, Ph. D., Associate Plant Pathologist (Hastings)
A. N. BROOKS, Ph. D., Associate Plant Pathologist (Plant City)
A. S. RHOADS, Ph. D., Associate Plant Pathologist (Cocoa)
STACY O. HAWKINS, M. A., Field Assistant in Plant Pathology (Homestead)
D. G. A. KELBERT, Field Assistant in Plant Pathology (Bradenton)
R. E. NOLEN, M. S. A., Field Assistant in Plant Pathology (Monticello)
FRED W. WALKER, Assistant Entomologist (Monticello)

*In cooperation with U. S. Department of Agriculture.















CONTENTS
Page
INTRODUCTION ............ ---------- -- ----- --- -------------------- 481
VARIETIES ........--.-.-- ---------- -------- 481
YIELDS ............-....--. ..-- -----. ------- ----------------------- --- ------ 483
SOILS ......................-..----- ----- --- -- ... 484
SETTING OF PLANTS .........-..-....--.. ----..------.------------- 485
SOURCES OF PLANTS .........--..-.-------.------.....- --------- ------ 487
FERTILIZER .....---......--------...---------------- ---------. 489
METHOD OF APPLICATION ........--... -----..- .---------------------. 489
CULTIVATION ..........--..------ -----.------. 490
MULCHING ..........---.---...-.---..--------- ...------------------- 490
FROST PROTECTION ......------- ---------.--- ------ -- ------ 491
IRRIGATION .........--...------..---.-- -- ----.----------. 492
PICKING AND PACKING ...-......--... -------------------------------.. 493
SHIPPING ...-..........-- ...--------- ---------------- ----- .. 496
Caring for and Loading Pony Refrigerators............---..-.....----- 497
Efficiency of Pony Refrigerators ......-....--..-...------ ---- ------- 497
Tests with Pre-Cooling Strawberries ......-...............--.--- ------ 498
DISEASES ....-....--..------- 4--------------------------- 499
A nthracnose .................--- ... ... ...----------- ---- --- 499
Crimps ..................... --. .. .-.--- -- .500
Root Diseases .................. ---- ---.---.--------------------------- 502
Leaf Spot Diseases .......--....------------- 506
Fruit Rots ................-------....----------- --- --- --- .. 510
Rules for Making Bordeaux Mixture ......-...........----..---.--.---.- 512
INJURIOUS INSECTS ....-...-- ......---.--------.. .....---------------- ---- 514
Red Spiders .....................-...------ .514
Florida Flower Thrips .......-..--.........------------- --------. 515
Pameras .......-----.... ..---------------.....- ---..--- ----------- 517
Cutworms .....--..--.....----------- --------. --------------- 518
Webworms ...................-- -- ------------------ 519
Mole-Crickets -...~.-..---..-....--....-..-. ...------- 519
Crickets ........... ..... .. .. .. -- .... -.. 520
White Grubs .............---..----------..-.--- ..-.-.------------------ 520
Grasshoppers --................ ...---------- ------------- 521
Earwigs .............-.....--..------------.----- ------------- 521
Flea Beetles ...................- -- -- --- ........ ... ... ..------- 521
Cowpea Pod Weevil .....-........-....--------- ------ ----........ 522
Aphids ....-........... --...--------------- -----......-- ------ 522
Negro Bugs ....----.....--..---....------------------....... 523












STRAWBERRIES IN FLORIDA
Culture, Diseases and Insects
By A. N. BROOKS, J. R. WATSON AND HAROLD MOWRY

Strawberry growing is of major horticultural importance in
Florida. The development of this industry is based upon the pro-
duction and marketing of fruit during the winter and early spring
months, December to May. Annual shipments of strawberries
from the state fluctuate between 4 and 8 million quarts, which
are produced on 2,000 to 4,000 acres and yield an annual gross re-
turn of $1,200,000 to $1,700,000 to the growers, or an average of
21 to 40 cents per quart. The nineteenth census of the Florida
State Department of Agriculture for 1926-27 shows a total
planting or 3,686 acres yielding 7,018,410 quarts, the fruit hav-
ing a valuation of $1,719,501.
Commercial strawberry growing in Florida had its beginning
in the late '70's near Gainesville and Mandarin. In the vicinity
of Lawtey, commercial plantings were first made in the early
'80's, which preceded any at Starke by two or three years.
Shortly after the freeze of 1894-95 strawberry growing was
begun in the Plant City area, the acreage there having increased
until it now comprises more than one-half of the state's total.
Due to a combination of several causes the commercial growing
of strawberries has long since been abandoned in both the
Gainesville and Mandarin areas, although the fruit is being
grown in these places in home gardens.
At the present time strawberries are being produced on a
commercial scale mainly in Hillsborough, Polk, Hardee and
Bradford counties, although smaller plantings for home use
and local markets are to be found in most counties of the state.
The season of shipment in the Plant City and other southern
areas extends from December into April and in the Starke-
Lawtey area from March into May.

VARIETIES

The varieties of strawberries which in the past have been
grown commercially in Florida are the Newnan, Hoffman, Cloud
and Klondike, and to a lesser extent Brandywine, Lady Thomp-
son, Excelsior and Nick Ohmer. These varieties, having been
found to lack one or more of the necessary qualifications of a







Florida Agricultural Experiment Station


good commercial variety, have been almost wholly discarded
and have been replaced by the Missionary.
The Missionary now is Florida's standard variety, it being
planted almost exclusively. This variety originated in Virginia
about 1900 and was introduced into the Plant City area some
ten or twelve years later. The characteristics which make this
variety desirable are a long fruiting season which lasts from
December to June, self-fertile blossoms, and heavy production
of fruit which is of good quality and size and firm enough to
withstand long shipment. It is easily propagated because of
its free production of runners. The plants are fairly resistant
to the ordinary strawberry diseases.
During three seasons, 1925-28, several different commercial
varieties of strawberries were tested on plots at Plant City and
Starke. Of these varieties, none were found to be equal to the
Missionary. Varieties tested were as follows:
Aroma-2, 4, 5 Lady Thompson-2, 4, 5
Big Late-4, 5, 6 Lupton-3, 4
Brandywine-1, 3, 4 Muse Special-(Identical with
Bubach-3, 4, 5, 6 Missionary)
Chance Seedling-2, 5 Nick Ohmer-1, 2, 3
Chesapeake-1, 2, 4 Norwood-4
Cooper-1, 2, 3, 4 Ozark-1, 2, 4
Dr. Burrill-1, 2, 3, 4 Parson's Beauty-2, 4, 5
Excelsior-2 Premier-1, 2
Famous-2 Sample-2, 6
Gandy--4, 5 Sen. Dunlap-1, 2, 3, 4
Glen Mary-2, 4, 5 Stewart Seedling-(Identical with
Haverland-2, 6 Missionary)
Horsey-4 The Best-1, 4
Klondike-5 Wm. Belt-1, 2, 4
The numbers following each variety refer to the reasons for
its undesirability as listed below:
1. Plants leaf-spot too severely.
2. Berries too small or too soft for shipping.
3. Surface of fruit too rough, not easily washed free of sand.
4. Flavor of fruit poor.
5. Plants too late in fruiting.
6. Imperfect blossoms.
The Missionary variety was found to be fairly resistant to
leaf-spots even when planted side by side with other varieties
which were killed by these diseases.
In addition to the commercial varieties listed above there
were tested several hybrid crosses made by one of the workers
of the United States Department of Agriculture. None of these
as yet has proven itself superior to the Missionary.







Bulletin 204, Strawberries in Florida


YIELDS

Strawberry yields will vary with cultural, soil and weather
conditions. No one commercial area in the state, over a period
of years, seems to have had consistently greater yields than
any other area. The table* below gives the average acre yield
in quarts in the Plant City area aver a period of six years.
S6 Year
Year 1917 1918 1919 1920 1921 1922 Average
Yield
in 1,948 1,932 1,515 2,268 2,476 2,120 2,043
Quarts


Yb. 0
I.l
--. a.


~I!! -F


W .: 4 ,, -A, .,- A 4
Fig. 126.-A plant of the Missionary variety.

The above figures are based on the fruit picked and mar-
keted. It may sometimes happen that because of a long fruit-
ing season or poor market prices obtaining near the end of the
season, all of the fruit is not picked. This might account for
apparent low average yields in commercial plantings when com-
pared with garden yields where every berry has been accounted
for throughout the full season. Maximum yields approximating
4,000 quarts per acre have been reported but such yields are
not to be expected ordinarily from large acreages.
*McKinley, Bruce and Funk, W. C. Univ. Record, U. of F. Vol. XXI, No. 3.






Florida Agricultural Experiment Station


SOILS

In Florida the soils best adapted to strawberry culture ap-
pear to be the darker colored grades of flatwoods soils under-
laid with clay, marl or compact sand, although with proper
treatment other types of soil can be made to produce good
fruit. Most of the present acreage is located on soils of the
Scranton series.
The qualities of soil necessary for successful growing of
strawberries are: (1) coherence without becoming too compact,
(2) fairly high organic matter or humus content, (3) neutral
to slightly acid reaction, (4) sufficient but not excessive soil
moisture and (5) adequate degree of fertility. Any soil meeting
these requirements, either naturally or artificially by means
of drainage, irrigation, plowing under of leguminous crops or
the application of fertilizers, will grow strawberries.
The lighter sandy soils need irrigation and the plowing under
of leguminous crops to increase their organic content, besides
applications of commercial fertilizers.
At present there is little or no commercial production of early
strawberries on muck soils. Such soils are more susceptible to
frosts than are the higher lands even immediately adjacent.
This situation would frequently cause the loss of early bloom by
frost. If found desirable to attempt the growing of strawberries
on muck soils, it is advisable to plant only lands which have
been under cultivation for several years. Strawberries produced
on muck soils tend to be too soft for shipping, but it is possible
that this tendency may be overcome by applications of potash
to the soil prior to and during the fruiting period. In some in-
stances on muck soils the fruit, even before maturity, will de-
cay on the side in contact with the soil.
In the event that strawberries are to be grown on marl rock,
these lands should be scarified to a depth of 6 to 8 inches prior
to planting and heavy applications of organic material added.
On such soils irrigation will be needed.
Since most Florida soils lose humus rapidly it is good practice
to grow some leguminous crop as velvet beans or Brabham or
Iron cowpeas every two or three years or oftener and plow
under. The vines should be cut up with a disk harrow and plowed
under three to six weeks before the land is to be planted to straw-
berries. During this period it is advisable to harrow the ground
whenever necessary to prevent the formation of a crust.







Bulletin 204, Strawberries in Florida


SETTING OF PLANTS

About 10 to 14 days before the strawberry plants are to be
set furrows are laid off the proper distance apart, and fertilizer
distributed in these furrows. The fertilizer should be well in-
corporated with the soil by means of a shovel-toothed cultivator
or other suitable tool so that the strawberry roots in no instance
will be in direct contact with large quantities of fertilizer at
the time of planting. The bed is made up directly over the fur-
row, the height of the bed being dependent upon drainage condi-
tions.
For the single row method the beds should be 36 to 40 inches
from middle to middle, and for the double row method, 48 to
60 inches. The beds are dragged and allowed to settle for a few
days prior to planting.
Both the single and double row methods of planting are used
throughout the strawberry growing areas.
Single row: In this method but one row of plants is set to
the bed. The plants are set 10 to 14 inches apart in the row,
which gives from 12,000 to 15,000 plants per acre, depending
upon the spacing of the beds and plants.
Double row: In this method two rows of plants are set on
each bed, the rows being 12 to 16 inches apart. The plants are
spaced 10 to 14 inches apart in the row; the plants in the two
rows being alternated rather than set opposite each other. It is
advisable to use a marker for laying off parallel lines for the
rows and to make use of some method or tool for spacing the
plants in the row. The number of plants per acre is from 15,000
to 25,000. (Fig. 125.)
The distance apart that plants are set will depend upon the
fertility of the soil and the time of planting. If the soil is fer-
tile the plants may be spaced closer together, as such a soil
will support more plants per acre. When set early in the sea-
son the individual plants will attain a larger size than when
planted late, and should therefore be spaced farther apart.
As a novelty, or where space is not available for the regular
systems of planting, strawberries may be grown by the so-
called "barrel" method. Any type of barrel is used but the
heavier ones are preferred. Both heads are removed, one-inch
holes bored at 10 to 12 inch intervals in the sides, the barrel
placed where wanted and filled with fertile soil. The plants are
planted by inserting the roots into the soil through the bored







Florida Agricultural Experiment Station


holes, irrigation being furnished by watering the soil at the
top. Any heavy box may be substituted for the barrel. By this
means considerable fruit may be produced on a very limited
area, but the method cannot be recommended for commercial
production.


Fig. 127.-Showing depths of setting plants. (1),
depth; (3), too deep.


too shallow; (2), right


The successful setting of strawberry plants is most easily
attained if the work is done during a good "season", i.e. when
the soil contains sufficient moisture without surplus water be-
ing present, and during cloudy days or late in the afternoon so
that the plants have some time to establish themselves before
being subjected to the hot sun.
The plants to be set should be removed from the nursery beds
by loosening the soil about the roots with a potato fork, care-
fully taking up the plants by hand; and after removing all the
old leaves and runners, tying them in small bunches. The roots
should not be allowed to dry out and, therefore, should be pro-
tected at all times from exposure to sun and wind.
In setting plants by the punch method it is necessary to have
one person to punch the holes, one to drop plants, and one to


L
Si~~Y i







Bulletin 204, Strawberries in Florida


set them. With the trowel method but two are necessary, a
dropper and a setter. At no time should plants be dropped far
in advance of the setter.
Strawberry plants should be set so that the bud and crown
are entirely above ground while the whole of the root system is
below ground. If set higher than this the roots are exposed,
causing the plants to dry out; if set lower, the buds will be
covered by soil, causing them to rot. Under Florida conditions
there is a greater tendency to set too low than too high. It is a
tiresome task to dig out about the buds of plants set too low;
consequently, care should be taken that the plants are set at
the proper depth. (Fig. 127.)
The holes made to receive the plants should be deep enough
and wide enough to accommodate the full length of the roots,
which should be spread out somewhat fan-wise and have the
soil packed firmly about their entire length. Merely packing the
soil about the base of the plant by a blow with the hand leaves
the main part of the roots in an air pocket, which causes them
to dry out unless a rain shortly after setting washes the soil
down around them.
Sometimes the beds may be fairly moist but the surface rather
dry, in which case the dry soil is scraped aside as each plant is
set. When this is done care should be taken not to set the plant
too deep in the hole thus made. At all times the bud should not
be below the surface of the bed.

SOURCES OF PLANTS

Plants are secured from the northern sources-mainly Mary-
land, Arkansas and Tennessee-each year during February,
March and April. These plants start growth immediately after
setting out and may bloom and fruit before starting to form
runners. If the flowering stalks are removed, runners will be
put out sooner. The plant beds are kept free of weeds and given
frequent shallow cultivation before the runners become too
numerous, so as to reduce the amount of hand work necessary
later on. In June or July the runner plants are removed from
the beds and set out on other beds prepared for them. These
newly set plants are allowed to make plants which will be used
for the final setting in September or October for fruit produc-
tion during the season extending from December to May.







Florida Agricultural Experiment Station


By following this procedure, it is necessary to obtain but 1,000
plants in February for each acre that is to be planted to straw-
berries in the fall. With careful cultivation and favorable
weather, 30,000 to 50,000 plants can be produced for fall plant-
ing from each 1,000 set out in February.
There is difference of opinion as to the relation of the time
of setting strawberry plants to the time and quantity of fruit
production.





















Fig. 128.-Method of propagating plants for fall setting.
In some instances the entire acreage desired for fruit produc-
tion during the coming season is set out in June, these plants
being allowed to make runner plants. In the fall all plants are
carefully removed from the beds except the mother plants
which are left for fruit production. Such a procedure will bring
in a revenue from the sale of plants and also leave the grower
large plants for fruiting. The advantage of a large plant is
that it protects much of its bloom during a light frost. The
plants which have produced runners are not likely to produce
early fruit.
Most of the final settings are made during September and
October, which, during a favorable season, allows the plant to
make considerable growth before producing fruit. If the plant-







Bulletin 204, Strawberries in Florida


ing is made after October 1 there are usually no runners pro-
duced, all the growth going into the making of a bushy plant.
By securing plants from northern sources each year, plant
diseases and insects are held in check more readily than by
carrying over Florida plants from year to year.

FERTILIZERS

The formulae of fertilizers used will depend upon the soils to
which they are to be applied and also the condition of the plants
at the time of application. Higher percentages of ammonia are
applied for plant growth and higher percentages of potash for
the coloring and firming of the fruit. Thus a 5-7-3* could be
used for the first application, a 5-7-5 for the second and a 3-7-7
for the final. The first application is made about ten days before
the plants are set out, the second at the time the first bloom
appears and the third some six weeks later. For each application
from 400 to 700 pounds per acre should be used, making the
total annual application 1,200 to 2,100 pounds per acre. The
time of application of fertilizers will vary according to moisture
conditions of the soil, in that if subsequent to the last applica-
tion the soil has been dry the plants will have had no opportunity
to utilize that already in the soil. Further fertilizing will be of
little or no value until soil moisture conditions are such as to
have brought the prior applications into solution, allowing this
to have been taken up, at least partially, by the plants.
All complete fertilizers used are made up of both organic and
inorganic materials. Generally, the organic materials consist of
tankage, castor pomace, cottonseed meal, fish scrap and goat
manure; while inorganic materials consist of nitrate of soda, sul-
phate of ammonia, acid phosphate and sulphate of potash. These
are used in varying amounts and percentages.

METHOD OF APPLICATION
The method of making the first application of fertilizer has
been described under the paragraph on the making of bed. Sub-
sequent applications are made by distributing the fertilizer in
furrows made by barring off the sides of the beds. The fertil-
izer is covered and incorporated with the soil by means of a
wide shovel cultivator.
*Percentages of ammonia, phosphoric acid and potash in the order
given.







Florida Agricultural Experiment Station


It is of major importance in applying fertilizer to mix it
thoroughly with the soil and not merely apply it in drills and
then cover it. Much burning of the roots has been caused by
improper application of fertilizers.
Occasionally during February or March the fruiting plants,
evidently through an inadequate supply of available nitrogen,
become sluggish. This lack of thrift can be overcome by the ap-
plication of a top-dressing of nitrate of soda, not to exceed 100
pounds per acre. Excessive amounts of quickly available nitro-
gen cause a softening of the fruit, which greatly impairs its
carrying qualities. Some success has been gained by the appli-
cation of a combination of nitrate and potash, either in the form
of potassium nitrate, 100 pounds per acre, or by two applica-
tions, first with potassium sulphate, 50 to 75 pounds per acre,
followed two to three weeks later with nitrate of soda at the
rate of 75 to 100 pounds per acre.

CULTIVATION

Cultivation is begun shortly after the plants are set and
should be often enough to keep down weed growth and prevent
packing of the soil. Deep cultivation is not necessary and should
be avoided. The amount of hoeing required will depend on the
frequency of rains and the weed growth. The manner of hoe-
ing is of importance. During the growing season, until the time
of fruit setting, a loose soil mulch should be left over the whole of
the bed rather than the compact soil surface which results from
the all-too-common practice of "shaving" the beds. Continued
usage of the latter method in the early part of the season ex-
poses some of the roots, and by leaving the plants set too high,
interferes with the formation of new roots by the drawing away
of the soil from the crown of the plant where new roots are
formed.
However, during the period of fruit production, a dirt mulch
on top of the bed is not desirable, as the fruit sinks easily into
this loose soil during rains, and subsequently rots.

MULCHING

Mulching is employed to keep fruit clean by preventing its
coming in direct contact with the soil. Pine straw (needles)
and native grass straw are the materials used. Mulching is







Bulletin 204, Strawberries in Florida


practiced in the Starke-Lawtey area. The fruit from mulched
plants is comparatively free of sand and washing is not neces-
sary. Usually when plants are not mulched, as is the case in
the southern areas, all fruit must be washed before packing.
The mulching material is generally distributed through the
field by means of carts or in large boxes fitted with handles for
carrying. It is scattered over the beds, completely covering the
plants which are later individually uncovered by hand. This
leaves the bed covered with the mulching material to a depth
of a few inches, the mulch being in direct contact with and under
the foliage of the plants. The time of application is usually de-
layed as long as possible to permit continued cultivation. The
material is commonly put on about the time the plants begin
to bloom.
The chief disadvantages of mulching are that it harbors in-
sects, particularly mole crickets, delays early fruiting due to
lower soil temperatures in mulched plots, and prevents cultiva-
tion, which, in some instances, results in excessive weed growth.

FROST PROTECTION

Protection of strawberry plants from frost usually is not
necessary in Florida, but during certain seasons considerable
loss of income has been experienced due to the ravages of cold
weather. A crop which requires as many months in preparation
as does the strawberry is well worth protecting from low tem-
peratures which will frequently stop the production of fruit for
four weeks or more, usually at a time when the fruit is com-
manding high prices. During the two seasons, 1926-27 and
1927-28, various methods of frost protection were attempted.
The methods employed, together with the advantages and dis-
advantages of each, are given below.
Cypress board troughs: Pecky cypress boards are nailed to-
gether to form V-shaped troughs which are inverted over the
strawberry plants to protect them during cold spells. To use
this method satisfactorily single-row beds are best, these run-
ning east and west, so that when the troughs are in the uncov-
ered position on the north edge of the bed they will not shade
the plants at any time during the day.
Troughs are made by nailing together two boards of even
length, one 1" x 10" and one 1" x 12", this giving an outside
dimension of 12 inches on one side and 11 inches on the other.







Florida Agricultural Experiment Station


A triangular brace is nailed in one end of each trough. Troughs
of these dimensions will cover plants which have a spread up
to 15 inches.
A total of 20,288 board feet of lumber is required per acre
when the beds are spaced four feet apart. Of this total, 10,816
board feet of 1" x 12" and 9,012 board feet of 1" x 10" are re-
quired for the sides and 460 board feet of 1" x 10" for the
braces. At a cost of $18 to $20 per thousand, this amounts to
$365 to $405 per acre for lumber. Since cypress lasts for 10 to
15 years the cost per acre per year is $25 to $40.
The advantages of the cypress board trough method is the
complete protection afforded and the ease and speed with which
the plants can be covered and uncovered. In considering any
other material used for frost protection it should be compared
with this cost per acre per year.
Pine needles or straw: This method is the one most widely
used and is fairly satisfactory, but due to the annual burning
off of the wood land, pine straw is becoming more and more dif-
ficult to secure.
The straw is gathered together in the woods, carried to the
strawberry field and distributed in the alleys. It is raked onto
the plants during the cold spells and carefully removed dur-
ing warm weather.
The disadvantages of this method as compared with the
troughs are that the protection is not so great, the process of
covering and uncovering the plants is not so readily effected,
some damage is done to the plants and fruit, and a fire hazard
is always present.
Its chief advantage is the low cost of material.
Paper: To some extent kraft wrapping paper has been used
as a means of frost protection. The paper is rolled over the bed
and the edges are held down by soil to keep the paper from being
blown out of place. The protection is fairly good but it is diffi-
cult to use the same paper for successive coverings and uncover-
ings. The cost of material per year is about equal to that of the
troughs.
IRRIGATION

To insure sufficient soil moisture in the strawberry fields at
all seasons of the year frequently it is necessary to have some
means of irrigation. There are three methods now employed.







Bulletin 204, Strawberries in Florida


Overhead irrigation: By this method water is sprayed upon
the ground from a system of .pipes supported 7 or 8 feet above
ground. A uniform distribution of the water is secured by
means of automatic oscillators. A full description of overhead
irrigation can be found in Farmers' Bulletin No. 1529 of the
United States Department of Agriculture.
The cost of installing such a system is fairly high but this is
offset by the low cost and ease of operation.
During the extremely dry summer of 1927 overhead irriga-
tion was used to great advantage in the propagation of plants.
In fact, it was possible to successfully set plants under irrigation
when this was not the case on unirrigated land. Freshly set
plants can be protected from the hot sun until they become es-
tablished by keeping the overhead irrigation going during the
heat of the day (10:00 A. M. to 4:00 P.M.) for three or four
days after setting.
Subirrigation: According to this method, water is applied to
the land by tiles placed 18 to 20 inches below the surface. The
water rises to the surface of the soil by capillary action. For
successful use of this method it is necessary to have a compact
subsoil fairly close to the surface so that the water will not be
lost by rapid seepage downward through the subsoil. The costs,
both of installation and of operation, of this method compare
favorably with those of overhead irrigation.*
Surface or Flood Irrigation: This method is the cheapest of
the three as far as cost of installation but is more expensive to
operate. The land must be brought to a proper grade so that an
even distribution of water can be effected without much wash-
ing of soil or ponding of water over beds in low places. The wa-
ter is allowed to fill up the alleys to the top surface of the beds.
To accomplish this and to prevent loss of water into the drain-
age ditches it is necessary to make use of a series of dams be-
tween the beds throughout the patch.

PICKING AND PACKING

Picking is done preferably in early morning when the fruit is
cool. The stems are pinched off in picking and ought not to be
more than 1/4 inch long, as longer stems interfere with proper
*(For a full description of this method consult Farmers' Bulletin No.
1348 and U. S. D. A. Bulletin No. 462.)


493







Florida Agricultural Experiment Station


packing. Fruits must not be snatched from the plant nor should
a number of berries be held in the hand at one time. After pick-
ing it is important that fruit be carried to the packing shed be-
fore long exposure to the sun. Close supervision of picking gen-
erally pays dividends.


Fig. 129.-A field packing shed.


If berries are picked from unmulched plants it is commonly
necessary to wash the sand from the fruit. When the fruit is
washed before packing frequent changing of the wash water
will result in less Rhizopus rot in transit. The berries should be
allowed to drain fairly dry before packing so that the cups will
not become wet and unsightly by the time they reach the mar-
ket. Well packed fruit, in clean white cups, is more attractive
and commands a better price.
None other than firm, ripe, fair sized berries should be packed.
All imperfect, decayed, green or small (less than 3/4 inch through
greatest diameter) fruit should be thrown out.
Culls may be packed and sold as such but it probably would be
better for the strawberry industry of the state if no culls were
packed and only a good grade of fruit put on the market in Flor-






Bulletin 204, Strawberries in Florida


ida as well as in the northern markets. This would no doubt
bring about a better price for the fancy fruit and result in a
more kindly feeling toward the industry by the Florida trade.
The containers used are the American standard boxes in pint
and quart sizes and the American ventilated crate of 32 quart
or 60 pint capacity.
The fruit should be packed firmly enough so that it does not
settle perceptibly in the cup before reaching destination. The
top is crowned slightly but not so much that the fruit is crushed
by the divider strips. Dividers with beveled cross strips are bet-
ter than the square ones as the former cut the fruit much less.
If a covered truck is not used for transporting the fruit to the
shipping platform the fruit should be covered with a light col-
ored, preferably white, cloth. Air should be allowed to circulate
freely about the fruit during the trip. This circulation will evap-
orate some of the water remaining on the berries from washing
and by this evaporation the temperature of the fruit is slightly
lowered.
Since Florida strawberries are sold as fancy fruit and as a
rule command a good price, it is the duty of every grower to see
that a quality pack of fruit is maintained. The U. S. Grade No.
1 should be observed in packing strawberries.

U. S. GRADE NO. 1*
"This grade shall consist of firm strawberries of one variety,
with the cap (calyx) and a short stem attached, which are not
over-ripe, under-ripe, undeveloped, decayed, or moldy, and which
are practically free from foreign matter and from damage
caused by sand, moisture, disease, insects or mechanical means.
The minimum diameter shall be three-fourths (/4) of an inch.
"In order to allow for variations incident to careful commer-
cial grading and handling ten (10) percentum, by volume, of
the berries in any lot may be under the prescribed size, and, in
addition, five (5) percentum, by volume, of the berries in such
lot may be below the requirements of this grade.

DEFINITION OF GRADE TERMS
'Diameter' means the greatest dimension at right angles to
a straight line running from the stem to the apex.
*More, C. T. and Truax, H. E., Preparation of strawberries for market.
Farmers' Bulletin No. 979. U.S.D.A.







Florida Agricultural Experiment Station


'Over-ripe' means dead ripe, becoming soft, a condition ne-
cessitating immediate consumption.
'Under-ripe' means so immature that less than two-thirds of
the surface of the berry is of a pink or red color.
'Undeveloped' means not having attained a normal shape and
development, owing to frost injury, lack of pollination, insect
injury, or other causes. 'Button' berries are the most common
type of this condition."

SHIPPING

Strawberries are shipped to distant markets by freight in
carlots under refrigeration or by express in pony refrigerators.
Local shipments are made in ventilated crates without icing.
More than half of the movement of strawberries from Florida to
northern markets is in 80-quart pony refrigerators, although
64 and 32 quart sizes are in use.
The present pony refrigerator is the result of much experi-
mentation on the part of shippers in the effort to secure a con-
tainer that would be satisfactory for transporting the fruit to
distant markets. The first "refrigerators" were huge boxes hav-
ing a capacity of 320 to 480 quarts of berries and several hun-
dred pounds of ice. These containers were aptly termed "jum-
bos." Because of the weight and unwieldy nature of the Jumbos,
several types of smaller boxes were later substituted antl from
these the present pony was gradually evolved.
The common form of 80-quart pony refrigerator is a box 26
inches high and 34 inches square. The walls are built of two
layers of cypress reinforced at the edges and corners. The in-
side is divided into two equal compartments by a galvanized
iron ice pan 5 inches wide and 151/2 inches deep, extending the
width of the box. Ventilating strips 7/8" x 1" are fastened verti-
cally on the inside walls and across the bottom of each compart-
ment and are so spaced as to properly support the cups of fruit
and allow circulation of air about them. A removable top ice
pan of galvanized iron 7 inches deep by 28 inches square is sup-
ported in a position immediately covering the center ice pan and
the two compartments. The top of the box is made of a single
layer of 7/8" cypress held together at the ends by battens. The
lid is fastened to the box by means of four bolts, the lower ends
of which are flattened and screwed to the inside walls of the box,






Bulletin 204, Strawberries in Florida


the other ends passing through holes in the battens of the lid
which is held secure by nuts. Canvas strips on the edge of the
box serve as gaskets. Drainage of melted ice is effected through
a hole from the top ice pan into the center ice pan and thence
through a drain to the outside.
These pony refrigerators are returned to the shipper as soon
as emptied and are used several times each season. If properly
stored when not in use they will last for many years.

CARING FOR AND LOADING THE PONY REFRIGERATOR
(1) Pony refrigerators should be clean and thoroughly dry
before being loaded with strawberries. (2) The center ice pan
should be filled with ice previous to loading with the fruit as
this will cool the refrigerator somewhat. (3) After the fruit is
loaded the top layer should be covered with a tough waterproof
paper which has been cut wide and long enough so as to allow 1
inch to be tucked down over the edges of the cups. This will
conduct any water accumulated on top the paper down the sides
of the refrigerator, thus protecting the cups of fruit below
from becoming wet. (4) The top ice pan is set in place, iced,
and the box allowed to stand as long as possible with the lid
off. This allows some of the field heat and moisture on fruit due
to washing to escape from the box. The refrigerator is then re-
iced and the lid fastened in place.
It is bad practice to place warm, moist fruit in an iced refreg-
erator and immediately fasten down the lid, because a sweating
process takes place which causes the accumulation of moisture
on the bottom and sides of the top ice pan with a subsequent
drip of water onto the fruit below. Under such treatment the
fruit will often arrive at destination in a soft and moldy condi-

EFFICIENCY OF PONY REFRIGERATORS
During 1927 some 300 inspections were made of fruit at desti-
nation and temperatures of the fruit taken. These temperatures
ranged from 36 to 46 degrees Fahrenheit, the majority being
near 38 degrees Fahrenheit. This shows that under the air tem-
peratures existing at the northern destination points at that
time the final temperature of fruit produced by the pony re-
frigerator is satisfactory, since Rhizopus rot develops but slow-






Florida Agricultural Experiment Station


ly below 46 degrees Fahrenheit. However, this low temperature
must be reached rapidly to prevent the development of this rot.
Consequently the pony refrigerator was tested to determine
the rapidity with which the temperature of the fruit is lowered.
These tests were accomplished by means of electric thermom-
eters of the thermocouple-potentiometer type, the thermocouples
being placed in fruit and air at various points within the pony
refrigerator and hourly readings taken. The results of these
tests show that the temperatures are lowered from 20 to 26
degrees Fahrenheit in the first 24 hours. When the initial tem-
perature of the fruit was fairly high (750 to 850 F.) it was not
lowered to 46 degrees Fahrenheit until 30 to 36 hours after the
closing of the refrigerator. Thus the pony refrigerator does not
cool the fruit down quickly enough to prevent the development
of Rhizopus when present.

TESTS WITH PRE-COOLING STRAWBERRIES
The benefits from chilling strawberries in a pre-cooling plant
where the air is rapidly circulated about the fruit are three.
(1) The temperature of the fruit is rapidly lowered below the
danger point (460F.) and (2) most of the excess moisture, due
to washing the fruit, is evaporated from it. Both the lowering
of the temperature and the drying of the surface of the fruit
will check the development of Rhizopus rot. (3) Pre-cooled
fruit will require much less ice in transportation to northern
markets.
These conclusions are based on the results of tests carried on
during 1926-28 and also of experiences of shippers who have
pre-cooled fruit before shipping it north.
In each of three tests made in 1927 an 80-quart refrigerator
of strawberries was cooled to 36 degrees Fahrenheit, iced and
shipped to New York with other refrigerators which had been
handled in the usual manner. At destination the temperature of
the fruit, both pre-cooled and not pre-cooled was about the same
(360 to 400F.) but in no case was any rot found in the pre-
cooled fruit, while some was present in the fruit which had not
been pre-cooled. In all three tests at destination the refrigerator
of pre-cooled fruit had twice as much unmelted ice in it as did
the refrigerator of fruit not pre-cooled. Thus pre-cooled fruit
can be shipped to more distant markets without re-icing of the
pony refrigerator being required.







Bulletin 204, Strawberries in Florida


STRAWBERRY DISEASES

A survey of the Florida strawberry fields made during the
past three years shows that in all strawberry-growing sections
the growers suffer losses from a number of diseases. In indi-
vidual fields certain diseases are serious and cause losses of
plants from 5 to 75 percent. Under favorable environmental
conditions it is possible that any one of the diseases now pres-
ent in the state may become widespread and cause considerable
loss to the strawberry industry. A means of minimizing this
possibility is for each grower to become familiar with the dif-
ferent strawberry diseases and the known methods of combat-
ting them. In following pages descriptions of the various dis-
eases, together with the known methods of controlling each are
given.
ANTHRARCNOSE
This is a newly described disease caused by a fungus, Colle-
totrichum sp., which apparently is confined to Florida; at least
it has not been reported elsewhere. The common name anthrac-
nose has been applied to this disease because of its characteristic
symptoms.
Under field conditions the runners only are attacked and hence
the disease is of importance merely in the "nursery" beds which
are used for propagation of plants and not in the "fruiting"
beds on which the plants are grown under the hill system and
kept free of all runners. The loss sustained is a decrease in the
number of plants formed on the nursery beds due to the disease
girdling runners, thus causing the death of the young plants
forming at the tips before they have taken root and become self-
supporting.
Anthracnose may appear to a limited extent during the spring
months but is most destructive after the first part of August and
up to the time when all runner plants are removed from the
beds. The disease is more severe during warm, moist weather
and in the moister areas of the strawberry fields.
Symptoms: A typical anthracnose spot as it appears upon
the runner is a small, oval, light brown, sunken area about 1/3
of an inch long when first noticeable, later gradually increasing
in size until it becomes from 3/ to 4 inches long and girdles
the runner. The older portion of the spot becomes shrivelled
and dark brown to black in color, and over its surface are scat-






Florida Agricultural Experiment Station


tered groups of setae of the fungus which can be seen under a
strong hand lens as small bristle-like tufts. Spores, by means of
which the disease is spread, are produced in great abundance


I,
Fig. 130.-Anthracnose, showing
typical lesions on runners.


in acervuli which develop in
these spots.
Control: Complete control of
S this disease has not been ef-
fected but it has been found
that applications of Bordeaux
mixture spray 4-4-50 at ten-day
intervals tend to check its rapid
development.
CRIMPS


A


The loss of plants, due to crimps, is 0-75 percent in individual
fields and about 2 percent for the entire state.
The disease may appear at any time of the year when the
plants are actively putting on new growth, in the nursery beds
during spring and summer and in the fields set for fruit pro-
duction in the fall. Cold weather checks the progress of the
disease and sometimes causes a masking of the symptoms, but
as yet no case of true recovery from crimps has been observed.
Crimped plants are worthless as fruit producers, because what
fruit they do put on is late and of inferior quality.


7


This malady is the most wide-
spread of any of the majot
diseases of strawberries in Flor-
ida, being found in all of the
areas of the state where straw-
berries are grown commercially.
It is known to Florida growers
as French bud, white bud, briar
bud, red bud or crimps. The
first two terms are misnomers
because the diseased buds are
not white or chlorotic, while the
other three are descriptive of
the symptoms of the disease.
Crimps is probably identical
with the "dwarf" disease in
Louisiana and the "red plant"
disease in Great Britain.







Bulletin 204, Strawberries in Florida


Symptoms: Crimps is fundamentally a bud disease, affecting
the young leaves as they develop. Affected plants, with but one
bud to the crown,
have aflat, spread *
ou t, spider-like
appearance, due
to a few normal
leaves having de-
veloped before
the disease ap-
peared. The de-
velopment of sub-
sequent leaves is
materially r e-
duced. These
leaves are de-
formed and range
in size from mere
rudiments to al-
most normal. The
leaflets are
crimped or crin- Fig. 131.-French bud, showing crimping of young
leaves.
kled, cupped, and
narrow, with a reddish cast to the serrations, main veins, and
petioles. In some cases the petioles are less pubescent than
normal, in fact, almost smooth. The older diseased leaves have
a darker green color than normal, and both old and young leaves
are more brittle.
The severity of the disease may result in the killing of the
main bud, with the subsequent death of the plant, unless lateral
buds chance to develop. The latter, in most cases, produce small,
normal-shaped leaves on long, spindly petioles. Plants with
multi-bud crowns may have both diseased and healthy buds, and
also produce both healthy and diseased runner plants. The usual
thing, however, is for all the runner plants of a diseased mother
plant to show the disease.
Causal Agent: Examination of diseased and healthy plants
shows that a microscopic eelworm or nematode (Aphelenchus
fragariae) is present in large numbers in diseased buds, from
50-1,300 per bud, but is not present in healthy buds. They occur
in the protected spaces at the bases of the young leaves and in
the folds of the leaves in the bud. These nematodes are from






502 Florida Agricultural Experiment Station

1/42 to 1/25 inch long and are colorless, and hence can be ob-
served only under a microscope. Experiments have proven that
crimps may be artificially produced by placing some of these
nematodes in the buds of healthy plants. The time required for
the symptoms to appear varies from 11 to 120 days, depending
upon temperature, moisture, and whether or not the plant is
putting on new foliage.
Dissemination: The disease is carried over from year to year
in the soil. Infestation is accomplished by rains or irrigation
water washing the nematodes into the plant buds. In moist
fields the nematodes can travel slowly from plant to plant, but
in fields which are inundated this spread of the eelworm is more
rapid.
The widest spread of this disease is caused by the removal and
resetting of diseased runner plants from the nursery beds.
Recently infested plants do not display crimps symptoms and
are thus used as healthy plants.
During the propagation of plants in the spring and summer
the runners formed by crimped plants usually become infested as
they push through the infested areas at the bases of the leaves.
This results in circular areas of diseased plants appearing in the
nursery beds.
Control: It is not likely that a spray will be found capable of
killing the nematodes without injuring the plants. A satisfac-
tory control of the disease may be accomplished by frequent in-
spections of the strawberry fields for the presence of crimped
plants and the removal of such plants from the field so that the
nematodes will not escape from the buds and reinfest the soil.
This means of control is especially satisfactory when applied to
nursery beds before much runner formation has taken place.
Crop rotation may also reduce the numbers of this specific
nematode in the soil.
ROOT DISEASES
There are several conditions which cause the destruction of or
at least interfere with the proper functioning of strawberry
roots, thus resulting in the death or dwarfing of the plants.
These conditions may be due to the presence of various soil
fungi, nematodes, soil toxins, lime, or concentrated solutions of
fertilizer.
Root trouble usually is manifested by a yellowing of the leaves
of affected plants or by a progressive dying of the leaf tissue
from the edges in toward the midrib.






Bulletin 204, Strawberries in Florida


ROOT ROT
Affected roots show all degrees of deterioration from a slight
brown spotting of the cortical tissue to a blackening and com-
plete sloughing off of that tissue. Fusarium sp., Rhizoctonia sp.,
and Pythium sp. have been isolated from infected roots. The
organism or organisms responsible for root rot have not been
definitely determined.
Symptoms: As manifested in the leaves the symptoms of root
rot are a progressive dying and drying out of the leaflets from
the edges in toward the midribs. An inspection of the roots
will show a rotting away of the root tips, a brown spotting on
the larger roots, and in extreme cases a complete rotting of the
outer tissues (cortex) leaving the central cylinder or conduct-
ing tissue exposed.
Control: There is no known means of controlling this trouble.
FERTILIZER BURN

Fertilizer burn is caused by the improper application of fer-
tilizer as has been described in the paragraph on application of
fertilizer. Proper methods of application
are also discussed there.
The symptoms for root rot as de-
scribed are equally applicable to
those caused by fertilizer burn, but
with the following
difference:
The spotting of the
roots is due to a burn-
ing by the fertilizer
and hence it will oc-
cur on that side of the
plant adjacent to the
applied fertilizer.
Fig. 132.- Fertil-
ROOT-KNOT izer burn of a
Root-knot is caused strawberry leaf.
by microscopic worms
belonging to the class called nematodes, which gain entrance
into the roots where they live as parasites upon the host plant.
The knots or abnormal enlargements of the roots are formed by
the tissues of the roots in response to the irritation caused by
the presence of the nematodes.







Florida Agricultural Experiment Station


^* *. A, '




Fig. 133.-Life history of the nematode, Heterodera radicicola (Greef)
Mull, (sizes not comparable). Top, four stages of development of the
egg. Nos. 1, 1, and 2, stages of growth of young worms. Nos. 3, 4, 6,
development of the female. Others, four stages in development of male.
(After Stone, G. E., and Smith, R. E., Mass. Agric. Exp. Sta. Bul.
55, 1898.)






Florida Agricultural Experiment Station


Symptoms: The only manifestation of the root-knot disease
in the above ground parts of the plant is the dying off of the
leaves of the badly infested plants. The roots of infested plants
are much enlarged at different points, most frequently at the
tips. These knots or enlargements are from 1/16 to 1/8 inch in
diameter, which is quite small in comparison with knots pro-
duced on the roots of various truck crops. Because of this small
size, root-knot of strawberry is often overlooked.
Control: Nematode infested land can be practically freed of
the pest by growing on the land only such crops as will not har-
bor the worms, at the same time keeping the land in a good
state of cultivation and free of all weeds. One summer of vel-
vet beans will do much toward controlling root-knot. Brabham
or Iron cowpeas are not so severely infested as other varieties.
For propagating beds the grower should select land which is
free from nematodes or treat the land before planting. The bed
is best sterilized by steam, but if this is not available, a double
treatment of sodium cyanide and ammonium sulphate, although
expensive, will give a very thorough cleanup. Directions for
applying this material may be obtained from the Experiment
Station.
LEAF SPOT DISEASES
In Florida leaf-spots make their appearance on the straw-
berry plants chiefly during late spring, summer and early fall
(April to October). Ordinarily they are of minor importance,
but in some instances spotting is so severe that some means of
control is necessary. Following are some of the factors which
tend to check the development of leaf-spot in Florida.
(1) The practice of renewing the strawberry beds annually
and obtaining new plants from the north each year, instead of
carrying Florida grown plants over from year to year.
(2) The fair degree of resistance of the Missionary variety
to leaf-spot as has been demonstrated by variety tests in Florida.
(3) The growing of fruiting plants under the hill system,
instead of the matted row system, thus giving a freer circula-
tion of air about the plants which somewhat lessens the accumu-
lation of moisture.
(4) The comparatively low temperatures prevailing during
the fruiting season.
There are three distinct leaf-spot diseases which will be de-
scribed below.






Bulletin 204, Strawberries in Florida


Badly infested roots fail to function properly in the absorp-
tion of water and the nutrients from the soil, which causes a
checking of plant growth and in severe cases a death of plant.
Damage caused by root-knot is more evident during periods of
drought than during periods of sufficient soil moisture.
Under favorable environmental conditions such as are found
in warm, well drained, sandy soils containing roots of suitable
host plants, nematodes are in the active or eelworm stage, but
when unfavorable conditions prevail, they are in an encysted
stage and are able to survive an adverse environment for a long
period of time, hatching out into worms when suitable con-
ditions again surround them. The main crop of strawberries
grown during the winter time is not so much affected by nema-
todes, as the worms are rather inactive during that time. Indeed,
strawberries can be successfully grown on heavily infested land.
But during the spring and summer time the attacks of worms
on the plants in the propagating beds are more serious.


wd U


Fig. 134.-Root-knot as it appears on strawberries.







Bulletin 204, Strawberries in Florida


COMMON LEAF SPOT
This leaf-spot, which is caused by the fungus Mycosphaerella
fragariae (Tul.) Lindau, is found in most of the strawberry
growing areas of the world. In Florida it appears to be the least
common of the three leaf troubles.
Symptoms: The spots are at first small, less than 1/ inch
large, and dark reddish or dark purplish in color. They increase
in size up to a maximum diameter of 1/8 to 3/16 inch, the cen-
ters become white or gray and the border is of the same color
as the immature spots.
The spots may number from one to many on each leaflet and
if extremely numerous cause the death of the leaflet. Although
a severe infection may result in the
death of the plant, under Florida condi-
tions this rarely occurs.
Control: Frequent applications o f
Bordeaux mixture 4-4-50 will control
this leaf-spot. During the
summer it is well to make
applications every two
weeks. In the fall after the
plants are set for fruiting
one or two applications will
suffice. The spray should
not be applied during the
time of fruit production as
it discolors the fruit and is
difficult to wash off. Fig. 135.-Common leaf spot on
difficult to wash off. strawberries.

LEAF SCORCH
The geographical distribution of leaf-scorch, which is caused
by the fungus Diplocarpon earliana (E. & E.) Wolf, is about
identical with that of common leaf-spot. In Florida it is more
abundant than is the common leaf-spot.
Although the disease is capable of attacking any of the green
parts of the plant, here it is confined mainly to the leaves and
is most important in the nursery beds during the summer
months. Ordinarily the frequent rains which occur during the
summer tend to keep this disease in check, but during the sum-
mer drought of 1927 in central Florida many plants were killed
by this disease.







Florida Agricultural Experiment Station


Symptoms: The young lesions of leaf-scorch appear on the
upper surfaces of the leaves as small purplish discolorations
which rapidly enlarge into irregular purplish blotches from 1/16
to 3/16 inch in diameter with minute dark glistening bodies
(the pycnidia of the fungus) present on the upper surface. The
spots on each leaflet may become so numerous that they coalesce
and give a reddish cast to the entire leaflet. In severe cases of
infection the edges of the leaf curl upward and the leaf dries
out progressively from the edge in to-
ward the midrib. The resulting dried or
scorched appearance has given rise to
the common name for this disease.
Control: Same as for common leaf-
spot.
LEAF BLIGHT
This disease, which
is caused by the
fungus Dendrophoma
obscurans (E. & E.)
Anderson, h as not
been reported from
so wide a range as
have the two -leaf spots
just described. It occurs
Fig. 136.--Leaf scorch. in Florida and has caused
some damage to strawberry plants, especially those set early
in the fall.
Symptoms: Even in the early stages the spots caused by this
fungus are larger than the mature spots of common leaf-spot
and leaf-scorch. From one to five spots may occur on a leaflet.
The young spots are circular and reddish purple in color. The
older spots become zonated. The central zone is dark brown sur-
rounded by a lighter brown zone which in turn is bordered by a
purplish zone, which blends into the normal green of the leaf.
In the advanced stages of the disease, the spots increase in size
until a V-shaped area is formed extending from one of the large
veins to the edge of the leaf. The area remains alive for a while
after displaying the purplish discoloration, but finally dies.
Small black dots, the pycnidia or fruiting bodies of the causal
fungus, appear in the central dark brown areas of the older spots.
Control: Same as for common leaf-spot.






Bulletin 204, Strawberries in Florida


MILDEW
This disease, which is caused by the fungus Sphaerotheca hu-
mili (D. C.) Burr., is of minor importance in Florida.
Symptoms: The disease causes a curling upward of the leaves
until much of the under surface is exposed. The causal fungus
grows superficially over the under surfaces of the leaves, form-
ing a white downy covering. In cases of heavy infection the
leaves are killed by the disease.
Control: Because of its unimportance in Florida, no work has
been done on means of controlling this disease. However, the
w ....


>i .- ----- -- ---------------
Fig. 137.-Strawberry leaf blight showing various types of lesions. The
leaflet in the upper left-hand corner shows a typical fan-shaped dead
area. (From Illinois Agric. Exp. Sta. Bul. 229.)


!JI







Florida Agricultural Experiment Station


New York Agricultural Experiment Station has demonstrated
that mildew can be controlled by applications of copper-lime
dust (15-85) put on at 12-day intervals.

FRUIT ROTS
At present there are four different rots known to attack
strawberry fruit in Florida. Three of these appear in the field
and ordinarily are not important from an economical standpoint.
One appears only during the shipping and marketing of fruit
and is often highly destructive.

LEAKS OR WHISKERS
This rot is of most importance in the shipping and market-
ing of strawberries although it may rarely be found in the field.


-I.. .--.


Fig. 138.-"Whiskers"


or "LLeaks."







Bulletin 204, Strawberries in Florida


It is caused by the fungus Rhizopus nigricans which rapidly de-
velops in fruit held above 500F. and in a moist atmosphere.
According to D. H. Rose in Dept. Circ. 402, United States
Department of Agriculture, an inspection covering seven years
ending 1925 showed that out of 387 shipments of Florida straw-
berries inspected Rhizopus rot was present in 7.5 percent.
Symptoms: The fungus readily attacks fruit that has been
injured and causes a collapse of the tissues and rapid extrac-
tion of the fruit juice which accumulates in the bottom of the
container and drips out, thus giving rise to the common name
"leaks" which has been applied to this trouble. The fruit settles
down until it only fills about one-half the container. A loose cot-
tony growth of mycelium of the fungus appears over the surface
of the fruit. This is the "whisker" stage. Later black dots ap-
pear scattered amongst the cottony mass. These dots are the
spore-bearing cases of the fungus.
Control: Fruit should be handled carefully so as to avoid
bruising. Frequent changing of the water used for washing
fruit will greatly reduce the source of infectious material. Fruit
picked early in the morning and protected from the sun during
the trip to the shipping point will have a lower temperature than
that picked later in the day. High temperatures favor the de-
velopment of Rhizopus rot. Hence the fruit should be cooled as
quickly as possible after picking. Rapid pre-cooling of fruit to
350F. before shipment will completely prevent the development
of this rot.
BROWN ROT OR GRAY MOLD
This rot, caused by the fungus Botrytis cinerea, occurs both in
the field and during shipping of fruit. It develops less rapidly
than Rhizopus rot and is of minor importance.
Symptoms: Fruit attacked by this fungus never becomes
"leaky" as is the case with Rhizopus. The spots attacked are
at first light brown, later dark brown in color, the flesh being
somewhat soft at first then becoming hard and dry. There is
no distinct line of demarcation between the diseased and healthy
tissue. Under moist conditions the infected fruit is covered
with "gray mold", the fruiting stage of the causal fungus.
Control: At the present time no means of controlling this
disease have been worked out. Infected fruit can readily be
identified and discarded during the packing process, thus pre-
venting further development of the rot during the shipping of
fruit.







Florida Agricultural Experiment Station


LIGHT TAN ROT
This rot, caused by Pezizella lythri (Desm.) Shear and Dodge,
is as important in Florida as that caused by Botrytis. It is easily
distinguished from the other rots.
Symptoms: The spots produced by this fungus are small,
sunken, and tan in color. They increase but slowly in size. The
infected tissue is a cone shaped core which, due to its dry corky
texture and to the disintegration of the cells adjoining, can be
removed intact from the sound tissues. This is the distinguish-
ing characteristic of the disease.
Control: Same as for Botrytis rot.

HARD BROWN ROT
This rot, which is caused by a fungus Rhizoctonia sp., is pres-
ent rather generally over the strawberry growing area of the
state, but does not cause any appreciable loss to the strawberry
industry.
Symptoms: The fungus causing the disease is present in the
soil. Thus initial infection of the fruit is on the side in contact
with the soil. Fruit in all stages of maturity may be attacked.
The spots are light tan in color unless soil has become enmeshed
in the fungal growth and is adhering to them, in which case the
spots are black or dark gray on the surface. A section cut through
the infected fruit shows that there is a dark colored band on the
surface of the infected area and a lighter tan colored area adja-
cent to and sharply separated from the healthy tissue. In fact
this line of demarcation is so sharp that the diseased tissue can
be cut away and the remainder of the fruit will be perfectly
edible.
Control: Infected fruit during packing should be carefully
sorted out so as to prevent development of the rot in the shipped
fruit.
RULES FOR MAKING SMALL QUANTITIES OF
BORDEAUX MIXTURE SPRAY
Since the average strawberry patch is from 1/2 to 3 acres in
extent, the quantity of spray mixture necessary for each appli-
cation is comparatively small. A method for making small quan-
tities of Bordeaux mixture, which is the most important fungi-
cide used in the control of the diseases of strawberries, is as
follows:







Bulletin 204, Strawberries in Florida


Bordeaux mixture spray: The cost of material and labor is
small compared with the beneficial results to the strawberry
plants.
Materials: (1) Rock lime or hydrated lime
(2) Bluestone, also known as blue vitriol or cop-
per sulphate.
Equipment: (1) Knapsack sprayer.
(2) Scales for weighing out the materials.
(3) One 50-gallon wooden barrel. (Coca Cola
barrel generally used.)
(4) Either another barrel as above or a 10- to
20-gallon tub or keg (not metal).
(5) One strong paddle for stirring mixture.
(6) One burlap sack.
Formula: The mixture recommended for the spraying of
strawberry plants is a 4-4-50, meaning 4 pounds of bluestone and
4 pounds of rock lime or 6 pounds of hydrated lime to 50 gallons
of water.
Procedure: (1) Dissolving the bluestone: Fill the small tub
or keg with water, or if two 50-gallon barrels are to be used, fill
one with 10-20 gallons of water. Place 4 pounds of bluestone
in a sack and suspend it in the water near the top surface. This
hastens the dissolving of the bluestone, which would take days
to dissolve, if placed in the bottom of the container. Allow all of
the bluestone to dissolve.
(2) Slaking the rock lime or preparing the hydrated lime:
Place 4 pounds of rock lime in the 50-gallon barrel, add just
enough water to thoroughly moisten the lime. As the lime be-
gins to slake, continue to add water slowly so that the lime does
not dry out, but not too much water to stop the slaking. The
lime should gradually crumble, boil with the evolution of consid-
erable heat, and finally form a thick paste. When all action
has stopped, add enough water to bring the contents of the bar-
rel up to 25 gallons. Stir well, thus thinning the lime-paste to
a milk-of-lime.
If hydrated lime is to be used, weigh out 11/2 times the quan-
tity given in the formula, which will be 6 pounds. Add to 25
gallons of water and mix thoroughly.
(3) Making the mixture: Slowly pour the dissolved blue-
stone into the milk-of-lime, at the same time having someone
constantly and vigorously stirring the mixture. When all the







Florida Agricultural Experiment Station


bluestone solution has been added, bring the contents of the
barrel up to 50 gallons by adding water.
Test for proper mixture: A clean knife blade when dipped
into the mixture and allowed to stay for a minute or two should
not show any copper deposited upon it. If the blade is coated
with copper, the mixture does not contain enough milk-of-lime
and more should be added until the mixture is correct.
Precautions: (1) In preparing Bordeaux mixture do not use
containers in which the solutions will be in direct contact with
a metal surface.
(2) Use the mixture immediately after preparation, as it de-
teriorates upon standing.
(3) Stir mixture well each time before filling the sprayer.
(4) Cover the surfaces of the leaves well with the spray. In-
secticides may be added to this spray mixture: for leaf-eating
insects 1 to 11/2 pounds of lead arsenate to 50 gallons of mixture;
for sucking insects 2/3 pint of "Black Leaf 40" to 50 gallons of
mixture.
INJURIOUS INSECTS

Under Florida conditions, as elsewhere, insects are of prime
importance in the economy of the strawberry industry. It is,
therefore, essential that the individual grower become well in-
formed concerning the various pests, the season during which
they appear, the plant parts attacked and damage done, together
with the known methods of controlling each. On the following
pages is given information concerning the more injurious in-
sects now known to attack strawberries in Florida.

RED SPIDERS, Tetranychus telerius
Red spiders frequently become very prevalent upon straw-
berry plants in the spring of the year when the weather is dry
and warm. They breed less rapidly in cool weather and the
heavy rains of summer usually very quickly bring them under
control; but during the spring when the weather is dry, they
often cause heavy losses. They attack both leaves and fruit.
The leaves turn a pale color and, if the infestation is heavy, be-
come dry and shrivel up and die. The young unripe berries take
on a brown color and also become hard and dry and fail to de-
velop. The injury is caused by the red spiders sucking the sap
out of the foliage and fruit. The mites themselves are reddish
or yellowish in color and, although small, are plainly visible to







Bulletin 204, Strawberries in Florida


the naked eye. They spin strands of silk which web up both sur-
faces of the leaves. They use this web as a road over which to
travel and also to hold the eggs to the leaves, and doubtless also
it lessens the danger of the mites being washed off by heavy,
dashing rains. They spread mostly by crawling from one plant
to another but may also be carried by the wind.
Like all members of the spider class, they are best controlled
by sulphur. If the weather is reasonably warm, one can ordi-
narily get satisfactory control by simply dusting the plants with
flowers of sulphur. This is, by all means, the quickest and most
economical way of combatting red spiders. Sulphur is best
spread with a dust gun but may be applied by hand. In order
to make it go through a dust gun more readily sulphur is often
mixed with 5 to 10 percent of hydrated lime, but the lime is not
necessary to kill the spiders. If this dust is applied in the morn-
ing when the plants are wet with dew, it will stick somewhat bet-
ter; but it can be applied any time during the day when there
is not a heavy wind blowing.
During cold weather better control will be obtained by spray-
ing the plants with lime-sulphur. One part of lime-sulphur to
50 gallons of water is used. However, this spray will taint the
berries and should not be used during the picking season, al-
though there will be no danger to the consumer. Nicotine sul-
phate and derris compounds (see below) are also good insecti-
cides for red spiders, but nicotine compounds also would be ob-
jectionable during the picking season.
In small dooryard patches which can be reached with the hose
or in a field provided with irrigation, a liberal sprinkling with
water will check these pests. The water should be applied with
as great a pressure as the plants will stand.
Life History: The eggs hatch out in some three to five days
and the young mites require about ten days for growth-more
when the weather is cool. About four days after they become
adults they begin to lay eggs. A generation usually requires
from two to three weeks; although it has been observed to be
as short as 10 days and as long as 35.

FLORIDA FLOWER THRIPS (Frankliniella tritici bispinosa)
This orange-yellow insect, about 1/25 inch long, is often very
injurious to strawberries in the spring. Its attacks are confined
entirely to blossoms where it feeds on stamens and young ber-
ries. Like the red spiders, these are sucking insects but their







Florida Agricultural Experiment Station


punctures are very shallow and very numerous. The action on
the berries resembles much that of the red spider but is more
largely confined to very young berries than is the case in at-
tacks by the red spider. As a result of their feeding the blos-
soms drop off, or the young berry may remain hard and brown,
failing to grow. In cases of less severe infestation the berry may
be deformed, due to the fact that it was injured on one side
and not on the other. These insects frequently seriously shorten
the bearing season of the vines as they are usually more abund-
ant in the later blossoms.
Control: One of the best sprays for thrips is nicotine sulphate
(one part of nicotine sulphate to 600 parts of water). To
make the solution spread better a little soap should be added
to the solution (2 or 3 pounds to 50 gallons, more if the water
is hard). This should be applied in the heat of the day as its
strength is soon dissipated after the application and the kill is
much better when the weather is warm. In fact, at a tempera-
ture below 60 degrees it is apt to be unsatisfactory. The spray
should be applied with as much force as possible as the thrips
have a tendency to hide down among the stamens and other
parts of the flower and will not be reached by the spray unless
good pressure is employed.
As this solution will taint the berries, it should be applied im-
mediately after picking. After 48 hours the odor and taste will
have disappeared from the berries.
A satisfactory dust for controlling this insect can be made by
mixing a very finely ground tobacco dust, such as snuff No. 2,
with an equal quantity of sulphur. This is not likely to taint
the fruit, as the dust will be knocked off in picking, and it has
the added advantage in that it will also control red spiders.
Preventive Measures: Weeds and other plants in bloom about
the strawberry patch should be destroyed as the thrips will
spread from these to the strawberry blossoms. This destruction
should take place some weeks or a month before the strawber-
ries bloom. The White-blossomed Spanish needle (Bidens leu-
cantha), a common plant about strawberry patches in the
southern part of the state, is a favorite host plant of thrips, as
are also roses.
Life History: The life history of this insect is very short--
two or three weeks when the weather is warm. The eggs are
laid in shallow slits in the stem just below the blossom. They







Bulletin 204, Strawberries in Florida


hatch out in three days into a light yellow nymph without wings
which continues to feed on the young berry and other tender
parts of the plant.
PAMERAS
Other very destructive insects which are liable to attack
strawberry plants in the spring are the pameras. Fortunately
they do not make their appearance in destructive numbers until
the bearing season is nearly over, but growers who attempt to
carry their vines through the summer almost invariably have
trouble with these insects. They breed so rapidly and are so
inconspicuous in color, size and habits that they often become
very .abundant before they are noticed. The young, in size and
color, resemble small yellow ants but they are much more rapid
in their movements than ants and the presence of the darker
winged adults will readily identify them.
This insect causes "buttons"-berries that in some early stage
of development cease to grow and become hard, dry and brown.
A very young berry will turn brown and dry up. Later the in-
sects attack the crown of the plant which withers rapidly and
dies if the bugs are numerous.
There are three species of these insects. The smallest of these,
Orthaea vincta, is black with yellow markings and about 1/5
inch long. This is the most common of the three. The larger
ones, Orthaea bilobata and Orthaea longulus, are much longer.
These bugs belong to the same family as the chinch bugs, the
most destructive enemy of the St. Augustine grass in Florida,
and they have the same "buggy" odor.
Control: The most effective insecticide is the tobacco extract
recommended for thrips. This must be applied with strong pres-
sure so that the liquid will be forced down into the crown of the
plants where the bugs congregate, usually just at the surface of
the ground. In small garden patches, particularly after the pick-
ing season, these insects can be brought under control by allow-
ing young chickens to have the run of the strawberry patch.
Like red spiders and thrips these insects tend to disappear as
the rainy season comes on. Many of them are killed by the
heavy, dashing rains. The insects are very abundant on wild
spurge (Euphorbia sp.). This not uncommon weed, which is
light colored and lies very flat on the ground and has a milky
juice, should be destroyed when in the neighborhood of a straw-
berry patch as a precautionary measure.







Florida Agricultural Experiment Station


CUTWORMS
Following their usual habit of severing succulent stems, these
caterpillars often cut off the petioles of the leaves of strawberry
plants or the stems of the young fruit. They also inflict another
type of injury by attacking the green but well grown fruit from
below, often hollowing it out until nothing but the shell of the
berry is left or they may make only a small hollow in it. This
is done without severing the berry from the vine.
Control: One of the best insecticides for cutworms and one of
the most cheaply applied is the poisoned bran bait. This is
made by mixing thoroughly 25 pounds of bran and a pound of
Paris green or one and one-half pounds of calcium arsenate.
The bran and poison should be mixed very thoroughly. Not less
than 10 minutes should be occupied in this mixing. This dry
mixture is then moistened with enough water to make it moist
but not sloppy, so that when sown it will fall in small flakes.
This will require about two and one-half gallons of water for
the 25 pounds of bran. This bait should be put out in the even-
ing after the sun has set so that it will not dry out and a few
flakes should be distributed around each plant. The 25 pounds
should suffice to cover four or five acres.
If cutworms are not sufficiently numerous to make this worth
while, they can be dug up and destroyed. If one will go through
the patch early in the morning and dig down an inch or so
under all severed leaves or berries he sees, he will usually dis-
cover the culprit without much trouble.
Preventive Measures: Cutworms are always worse in beds
made up on ground which was occupied by heavy sod. If such
land is to be used for making the strawberry beds, it should be
plowed two or three weeks before the berries are set. Then, ten
days or two weeks after plowing, the poisoned bran bait recom-
mended above should be sown broadcast over the land in the
evening. The cutworms, rendered very hungry by their long
fast caused by the destruction of the grass, will eat this poisoned
bait eagerly and a thorough clean-up should result. Instead of
the poisoned bran mash one may scatter over the ground leaves
of mustard or collards or even grass which have been dipped in
a strong solution of lead arsenate, using an ounce or two to
three gallons of water.







Bulletin 204, Strawberries in Florida


WEBWORMS

Other caterpillars often very injurious to strawberry beds are
the webworms (Crambus sp.). These insects get their name
from the fact that they construct near the surface of the ground
a web in which they spend most of their time, coming out occa-
sionally to feed on the strawberry plants. Like cutworms, these
insects are worse on land which supported a heavy sod before
the strawberries were put out, and the poisoned bran bait rec-
ommended for cutworms will usually give sufficient control of
these insects. Should it fail to do so, the plants should be
sprayed with a solution of lead arsenate, using one and one-half
pounds to 50 gallons of water. Put into the solution a pound
or two of soap or the milk obtained by slacking two or three
pounds of quick lime in warm water. Of course, lead arsenate
should not be used during the picking season or immediately
before it.
Preventive Measures: These measures will be the same as
that for the cutworm.
MOLE-CRICKETS
These dirty white or yellowish insects make burrows just be-
low the surface of the ground by means of their enlarged front
legs. These burrows resemble much the runways of moles but
are very much smaller, only about an inch in diameter. During
the day the insects live deep in the ground but come out at night
to feed and are very destructive to vegetation. There are three
species commonly met with in Florida. Two of them, Gryllo-
talpa borealis and Scaperiscus abbreviatus, are native insects
and are confined mostly to low ground. The third species has
been introduced from the West Indies where it is known as the
"Changa." This one works in well drained land and is very com-
mon and destructive in parts of the state where it has been col-
onized. Fortunately, it is not as widely distributed as the other
species.
Control: Poisoned bait made by thoroughly mixing 25 pounds
of cornmeal with a pound of Paris green and then moistened
with two gallons of water, to which a quart of molasses has been
added, has given good control in Florida. This should be sown
broadcast over the land where mole-crickets are noticed in the
evening. Some growers add to this some citrus fruit (see under
grasshoppers), and cottonseed meal may be substituted for
cornmeal.







Florida Agricultural Experiment Station


Another method of dealing with them is to fumigate them
with some soil fumigant. For this purpose one may use carbon
bisulphide or a solution of cyanide made by dissolving an ounce
of sodium cyanide or two ounces of calcium cyanide in a gallon
of water. For a thorough clean up by this method, the land
should first be plowed, then smoothed and packed with the back
of a shovel. In the morning go over the bed and wherever dis-
turbed earth is seen, indicating the presence of mole crickets,
run a sharp stick down to the depth of three or four inches and
pour into this hole a tablespoonful of carbon bisulphide or two
or three tablespoonfuls of the cyanide solution. Immediately
tramp the soil solid over the hole. This process is repeated every
morning until no more signs are seen. This should give one a
very good clean-up of mole-crickets, but this must be done be-
fore the beds are planted. If the soil is dry, wet it before com-
pacting it. If land intended for strawberries is known to be
infested, it would be an excellent idea to pasture hogs on it two
or three weeks before plowing it.
During March and April large numbers may be caught in
light traps. Suspend a lantern in the field and under it, place
a pan containing water with a little kerosene on the surface.

CRICKETS

Crickets are often numerous underneath the mulch of straw-
berry beds. From these hiding places they come out, particularly
at night, and feed on the ripening berries. They usually eat out
small pits in the berries which soon decay. The poisoned bran
bait mentioned above for cutworms or the grasshopper bait are
about the best poisons for crickets.

WHITE GRUBS

Sometimes the roots of strawberry plants are eaten off by
large white grubs, the larvae of June bugs or May beetles. This
type of injury will be found most frequently where heavy sod
land has been plowed up for strawberry beds. If many of these
grubs are found in the soil when the beds are being made up,
the grubs should be exterminated before the plants are set out.
This can be done by allowing hogs to run in the field for a few
weeks or the ground may be treated with calcium cyanide. This
should be spread in front of the plow when the bed is being







Bulletin 204, Strawberries in Florida


plowed, at the rate of about 300 pounds per acre. It should be
laid down in the bottom of the furrow, immediately in front of
the plow which will promptly cover it over.

GRASSHOPPERS

These well known pests of practically all garden and field
crops occasionally attack strawberry plants, eating large holes
out of the leaves. They are best controlled by poisoned bran bait.
This is made by mixing thoroughly 25 pounds of bran and a
pound of Paris green. It must be mixed very thoroughly while
still dry, as recommended above for cutworms. When thorough-
ly mixed, moisten the poisoned bran with a solution made by
adding a quart of cane syrup and a half dozen lemons or other
citrus fruit to two and a half gallons of water. The citrus fruits
should be grated or chopped up fine, rind, pulp and all, and the
bran should be moistened with this solution until it is damp but
not sloppy, so that when sown broadcast over the soil it will
fall in small flakes. Instead of the Paris green one may use
one and one-half pounds of calcium arsenate, but lead arsenate
had better not be used as it is so heavy that it is difficult to get
a good mixture. Sodium arsenite may also be used. This sub-
stance may be added to the solution instead of being mixed dry
with the bran. This will reduce the amount of labor necessary
to make up the poisoned bran bait and will usually give a more
even distribution of the poison than when the bran and poison
are mixed dry. Poisoned bran bait should be put out early in
the morning as grasshoppers do not feed much at night.

EARWIGS

These dark colored insects with a pair of pincher-like organs
on the end of the body are often very abundant in low grounds.
They feed on the roots of the plants and often come out at night
and feed on the foliage and berries. The poisoned bran bait
recommended for grasshoppers is perhaps the best means of
control.
FLEA BEETLES

Several species of Flea Beetles, more especially the straw-
berry flea beetle, Haltica ignita, a yellow-bronze insect about
1/5 inch long, attacks strawberry leaves, eating round holes in
them.







Florida Agricultural Experiment Station


Control: The best control for these insects is to spray the
plants with Bordeaux, to each 50 gallons of which a pound of
lead arsenate has been added. If the attack occurs during the
picking season, the use of arsenic in any form should be avoided.
A good insecticide to use under those circumstances would be
one of the pyrethrum compounds.
One of the favorite food plants of this beetle is the orna-
mental, crape myrtle. This plant should not be grown in close
proximity to a strawberry bed or at least it should be watched
closely during the spring and sprayed with lead arsenate in case
the beetles appear on it.

COWPEA POD WEEVIL, Chalcodermus aeneus
This black weevil, about the size of a boll weevil, is a very gen-
eral feeder and sometimes in the early spring attacks the straw-
berry plants. If the attack does not occur during the picking
season, a spray with lead arsenate will afford protection. If the
attack does occur during the picking season, the best plan is to
go through the patch in the early morning when the weevils
are sluggish and, with the hand or a stick, knock the beetles off
into a flat dish containing a little kerosene in the bottom.

APHIDS

The strawberry root aphid, Aphis forbesi Weed, sometimes
attacks strawberry plants, sucking the sap from the roots. It
can be controlled by punching holes slantingly under the plants
and pouring in a tablespoonful or so of carbon bisulphide. The
hole should be several inches from the plant, but both the dis-
tance from the plant and amount of carbon bisulphide to use
will vary with the character of the soil. In heavy, dense soils
more of the material will be needed and the distance from the
plant will need to be shortened as the gas does not penetrate
heavy soils as well as light, open, sandy ones.
Other species of aphids will attack the part of the plant above
ground, the crown, etc. They are best controlled by tobacco ex-
tracts, such as nicotine sulphate. This may be applied either
as a dust mixed with lime or as a liquid spray. Dusting will be
much quicker but it will take more of the material. A good dust
is made by thoroughly mixing three and three-fourths pounds of
nicotine sulphate with 50 pounds of hydrated lime. The mixing
must be thorough. It should be done in a barrel rigged up for







Bulletin 204, Strawberries in Florida


this purpose (see Bulletin 183, Fla. Agr. Exp. Station). This
dust should be applied in the heat of a good, warm day and
when there is not much wind blowing.
If the spray is used, one part of nicotine sulphate should be
used to 600 parts of water and to every 50 gallons, three or four
pounds of soap should be added to make it spread and stick bet-
ter, or the nicotine sulphate may be added to the Bordeaux mix-
ture. Derris compounds may be used instead of nicotine sul-
phate.
NEGRO BUGS OR BURROW BUGS
These are small, roundish, shiny black bugs which are some-
times found damaging the roots of strawberries or they may at-
tack the berries, whose juices they suck. They have a very
nauseous odor, suggesting that of bedbugs. The adult bugs are
about 1/8 inch long. The middle piece of the back is enlarged so
that it covers the entire abdomen, which makes the insect look
more like a beetle than a bug; the sucking mouth parts, how-
ever, readily distinguish it as a bug.
Control: A spray of crude carbolic acid, a tablespoonful to
two gallons of water, has been found to be very effective in driv-
ing these bugs away; but if they occur during the picking sea-
son it should be applied just after the berries have been picked.




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