COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS
STATE OF FLORIDA
COLLEGE OF AGRICULTURE. AGRICULTURAL EXTENSION SERVICE
UNIVERSITY OF FLORIDA, AND COUNTY AGENT AND
UNITED STATES DEPARTMENT Vegetable Crop Specialists HOME DEMONSTRATION WORK
OF AGRICULTURE, COOPERATING E G 1- A IR J A N GAINESVILLE, FLORIDA
No. 19 April 17, 1953
MR. COUNTY AGENT:
SEEDBEDS---late or early?
Expect your first reaction to the above was that it's too late to worry about
seedbeds. Granted, but we're trying to be early for the fall plantings---now's
a good time to review seedbed difficulties experienced this past season and to
note tentative plans for trial demonstrations for the next crop. Growers might
be particularly receptive...
Mr. Don Burgis, Gulf Coast Station, is cooperating to make available to you
his recent summarization on herbicides, nematocides, and soil fungicides for
vegetable seedbeds. We'll be more than pleased to forward mimeographed copies
on your request. It's to the point, practical, and covers use of MC-2. allyl
alcohol, EDB, DD, and copper drenches. Ask for it...
BOTRYTIS---another rampaging disease.
It's been observed on other crops and in other areas, but we've asked Dr. J. M.
Walter, Gulf Coast Station, to trace out some developments of the past season for
you. He says:
"During the winter of 1952-53 many tomato growers suffered severe losses be-
cause of gray mold, caused by Botrytis cinerea. Cool, damp weather favorable for
the increase of the fungus prevailed for many weeks. The disease develops par-
ticularly beneath heavy foliaged vines on the ground and makes the problem of
application of a fungicide (if a control was available) quite difficult. Though
present, Botrytis is not an important problem on staked tomatoes.
"Experience has made it obvious that the fungicides nabam and zineb, are not
effective against Botrytis. There have been indications that phv:on XL, which is
very effective against late blight but not effective against gray leaf spot (red
rust) and early blight, is relatively effective against the Botrytis disease."
Your tomato growers should know that Dr. John F. Darby, Indian River Station,
is studying this disease closely and is obtaining encouraging results with cer-
tain fungicides. The problem of coverage still remains, and attempts at control
include key applications before the plants 'go down'. We hope to present you with
Dr. Darby's latest findings when they are available for our use.
GHOST SPOT---tomatoes and teamwork.
Another interesting angle on Botrytis cinerea...English investigators indi-
cate that "Ghost Snot" (check Figure 46-PB 1934) may be caused by the penetra-
tion of the surface of the tomato by spores of the fungus. They say these infec-
tions occur only when humidity is high, and apparently the fungus does not sur-
vive in the fruit. Drs. Darby and Walter are investigating this possibility.
A research team organized by Director W. M. Fifield recently reviewed the
"knowns and unknowns" of ghost spot, in cooperation with county agricultural agents
surveyed the Immokalee-Devil's Garden area where ghost spot has been particularly
prevalent, and concluded that Botrytis should be tested thoroughly as a likely
causative agent before further studies are undertaken.
CALCIUO---seems the key to blackheart.
Looks like Dr. C. M. Geraldson, Gulf Coast Station, really has something in
foliar applications of calcium for control of blackheart of celery. There's still
plenty of checking to be done, but---Dr. Geraldson says:
"We have been using foliar applications of either .05M calcium nitrate or
calcium chloride with equal success for the control of blackheart. Commercially,
that would be about 10 bs./100 gallons of calcium nitrate and about 5 lbs/100
gallons of calcium chloride.
"During the Fall season such applications weekly controlled blackheart 100
percent. The check plots contained about 50 percent blackhearted plants. Treated
plots yielded about 150 percent more marketable celery. Spring trials sre now
being carried on where concentrations are being increased. That may be desirable
as some growers are experiencing difficulty in controlling blackheart, especially
when it is quite severe. The .05M treatment can be applied 2 or 3 times weekly
and literally poured on if that is desirable.
"More likely the main difficulty is proper application, The calcium must
reach the heart area in order to be effective. Let me emphasize that point I
have yet to find a celery plant no matter how severely blackhearted, that will not
respond to calcium treatment 3 to 5 days after application. If secondary inf.a -
tion such as soft rot is prevalent it may be too late, or if sufficient calcium
does not reach the heart area as the heart continues to grow, the treatment will
not be successful.
"Good farming practices which have previously been recommended for control
of blackheart should be utilized in conjunction with the foliar calcium treat-
The research isn't closed out, but it's interesting to check back through
past Vegetarians (2, 10, 14) and follow the progress of research by Dr. Gerald-
son and Dr. P. J. Westgate, Sanford Station. It's a good piece of work and will
mean a lot to the celery industry.
Notes on Highlights
POTATO INVESTIGATIONS LABORATORY FIELD DiY
(Dr. A. H. Eddins, Dr. E. N. McCubbin, Dr. T. M. Dobrovsky, and Dr. Nathan Gammon)
Cabbage and Cauliflowei Varieties: Cabbage varieties recommended for commercial
production: I-ed. Copenhagen Res. a (yr); Med. Copenhagen Res. b (yr); Bonanza;
Early Glory of Enkhuizen; Glory of Enkhuizen; Marion Market (yr); Copenhagen
Market 86; and Red Acre. Cauliflower varieties recommended for commercial pro-
duction: Snowball X; Snowball Y; Snowdrift; and Holland Erfurt.
Lettuce 'Drop': Variety test results were complicated by Sclerotinia or 'drop'.
It seemed significant to note that a treatment of 1,000 lbs. cyanamide applied
60 days prior to planting was not successful in controlling the disease in these
Chelates: Sequestrene-metal chelates of iron, zinc, manganese, copper, magnesium,
calcium and cobalt, were being tested at varying rates in the soil. The check
plots, i.e., those not receiving chelates, were best. At relatively high rates,
the chelates were injurious in these tests.
Whiptail: Correction of the soil pH and applications of molybdenum in very small
amounts have given control of whiptail in Snowball A. Snowball X is resistant,
It was indicated that molybdenum applied to the soil last year was retained to give
control this season.
Systemics: The systemics gave outstanding control of aphids. The residue problem
remains; even methods of analysis for systemics have not been worked out.
Corky Ringspot: This disorder affects the tuber surface and gives a certain amount
of internal discoloration of potatoes. Corky ringspot is present in the Hastings
area and seems to be spreading. No controls are known. It was thought last year
that there was some relationship between plowsole and corky ringspot. Varieties
and selections are being screened for possible resistance and other attempts at
control are being studied; i.e., chiseling the land.
Notes on Highlights
SUB-TROPICAL EXP~ERII-INT STATION TOTMTO FIELD DAY
(Dr. Geo. Ruehle, Dr. R. A. Conover, Dr. J. L. Malcolm, Mr. J. C. Noonan, and Dr.
D. 0. Wolfenbarger)
Tomato Varieties: Some of the newer lines show promise for the Homestead area.
STEP 176 rates high in size but is slightly flattened. STEP 193 r&tes high in pto-
ductivity but later than Homestead and Jefferson. STEP 89-4 is an indeterminate
selection of Homestead; several weeks later than Homestead but considerably more
vigorous; probably would make a better tomato for staking or putting on 8 foot rows.
Stokescross #2 is a second generation hybrid showing considerable vigor and Fusar-
ium wilt resistance.
Soil Rot: Rhizoctonia solani is the principal rot affecting tomato fruit in the
area. Records of several seasons show that 20% of the total yield of spring toma-
toes is affected. Treatments with thiram, captain, and pentachloronitrobenzene were
sprayed on the soil surface after the tomatoes were "laid by". The pentachloronitro-
benzene was particularly promising last year.
Fungicide-Yield Tests: There is considerable discussion on the relative effects of
certain fungicides on tomato yield and disease control. Plots were designed to meas-
ure such differences as 1- and 2 lbs. zineb; nabam plus zinc sulfate with and with-
out spreader-sticker; two forms of nabam plus manganese and the commercial mix.
Blight Resistant Tomatoes: Excellent progress had been made toward breeding a late
blight resistant tomato when a new and virulent race of the-fungus appeared in last
year's planting. The sources of resistance succumbed to the virulent race as did
all their progenies. The virulent race is present again this year. Most plants,
while perhaps appearing to be resistant, have some normal sporulating lesions of
Fertilizers: Tomato plant differences were observed under varying rates of N. P and
K, a soluble fertilizer spray test, and a nitrogen-potash ratio test. Yield response
had not been determined. Final results should be interesting; e. g., it appeared
that the plants in zero-phosphorous fertilizer plots continue to look good after sev-
eral seasons tests.
Insecticides: Parathion and EPN gave outstanding control of serpentine leaf miner
and aphids, on tomatoes and gave satisfactory control of worms where regular weekly
applications were made. Unless regular weekly applications are made, and if a se-
vere worm infestation should occur, they may not give satisfactory control of worms.
Control of worms may be obtained by either of the following: DDT 2 lbs. 50% w.p.
or 1 qt. of 25% emul.; toxaphene 21 lbs. 40% w.p. or l1 pts. of 60% emul.; TDE-
(DDD, or rhothane) 2 lbs. 50% w.p. or 1 qt. of 25% emul.
OTHER VEGETABLE FIELD DAYS COIING 2UP---you'll see individual publicity on them. See
that it gets passed on to growers and industry contacts.
Indian River Field Laboratory Ft. Pierce April 28 1:30 PM
Gulf Coast Experiment Station Bradenton April 29 10:00 AM, repeat tour 1:30 PM
Eierglades Experiment Station Belle Glade April 30 1:30 PM
Main Station Gainesville May 21 9:30 AM
Assistant Vegetable Crop Specialist