FLORIDA AGRICULTURAL EXTENSION SERVICE
UNIVERSITY OF FLORIDA
INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES
Vegetable Crops Department
George A. Marlowe, Jr. James Montelaro
Chairman Vegetable Crops Specialist
Mason E. Marvel James M. Stephens
Associate Vegetable Crops Specialist Assistant Vegetable Crops Specialist
April 14, 1970
TO: COUNTY EXTENSICOi DIRECTORS ANJD VEGETABLE A.'E;ITS
VEGETAR lAi (88)
IN THIS ISSUE:
I. Success or Failure with Herbicides?
II. bottling of S2:imer Sfuas.
III. Label Extended for DiBP for Potato Vine-Killing.
IV. Hlighlight Notes from Central Florida Field Pay Reports:
A. Fertilization of Direct Seeded Cabbage.
B. Sting nematode Control in Cabbage.
C. Cabbage Variety Trials.
D. Looper Control on Cabbage.
1. Success or Failure with Herbicides?
The vegetable grower expects to get good weed control without
injury to the crop everytime he uses herbicides. From experience, we
know that this is not always the case. The first reaction is to put
the blame on the effectiveness of the herbicide. In most cases, the
fault lies with the grower or the foremen who fails to apply the chemical
Herbicide application is one of the most exacting cultural
practices used in vegetable production today. Over the years, we have
observed poor weed control or crop injury resulting from mistakes made
in land preparation and use of equipment. Rather than attempt to dis-
cuss correct application techniques in detail, it may be more helpful
to just list the mistakes that have been observed in the hope that grow-
ers may be able to avoid these in the future.
(1) Poor Land Preparation
(a) Excessive undecayed plant residues.
(b) Too many clods.
(c) Surface of soil not level and not finely prepared.
COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS. STATE OF FLORIDA. COLLEGE OF AGRICULTURE,
UNIVERSITY OF FLORIDA, U. S. DEPARTMENT OF AGRICULTURE, AND BOARDS OF COUNTY COMMISSIONERS. COOPERATING
(2) UJrong Timing
(a) Applied too early, too late, or under adverse
weather conditions resulting in crop injury,
reduced weed control, etc.
(3) Wrong Rate
(a) Too high causing crop damage.
(b) Too low resulting in poor weed control
(4) Wrong Herbicide
(a) Not recommended for the crop or specific weed problem.
(5) Improperly Placed Herbicide
(a) Too deep
(b) Too shallow
(c) Misplaced when applied directionally
(6) Drilled Row Surface Not Properly Shaped
(a) Herbicides leaching into drilled row when left concave.
(b) Herbicides leaching away from drilled row when over-
(7) Poor Soil Moisture Levels
(a) Low soil moisture hindering activity of herbicide.
(b) Excessive irrigation or rain causing movement of
herbicide away from desired zone.
(8) Use of Urong Equipment
(a) Equipment not suited for herbicide application.
(b) Equipment not maintained adequately.
(9) Inadequate and Infrequent Calibration
(a) Application rates of both granular and spray equip-
ment changes with wear and time.
(10) Movement of Soil
(a) Cultivation causing movement of soil away from or to
II. Mottling of Su::, er Suashi
The question of 'what causes my summer squash to be mottled with
patches of green and yellow" arises every year during the spring season.
Squash with these symptoms is usually infected with a strain of watermelon n
Mosaic Virus. It is not seed-transmitted, so it cannot be blamed on the
seedsman. Actually, it is transmitted primarily by winged aphids from
host plants of the vine crop family or certain other crop plants and weeds
commonly found in the vegetable growing areas.
The disappointing aspect of this problem is that adequate aphid
control in the crop may not prevent the infection. The aphid requires
only a short period of time to infect a plant. Furthermore, even if the
squash planting appears to be completely free of aphids, sufficient
winced aphids may be present to spread the virus rapidly.
III. Label Extended for Di;BP for Potato Vine-Killing
At the time the last Vegetarian was written, Dinoseb (DilP)
could not be recommended as a potato vine-killer because the label had
not been extended beyond January 1, 1S70. Since then, we received word
that the label has been extended to January 1, 1971. Dinoseb is now
the coined or common name for several formulations of the dinitro com-
pounds. Growers using DNBP, which is now recommended for killing potato
vines, should read the label carefully as formulations vary in percentage
of active ingredients.
IV. Highlight i'otes from Central Florida Field Day Reports
The vegetable field day held at the Central Florida Experiment
Station at Sanford, Florida, on March 3, 1970 was most informative.
Following are some highlights from four of the reports.
A. Fertilization of Direct Seeded Cabbage
Dr. R. B. Forbes, in attempt to determine the best fertilizer
program for direct seeded cabbage, tested 13 treatments where timing, sources,
placement, etc., were included. I!hen the plants were 48 days old, the
best plants were in the following treatments.
1. Band, 5-2-9 liquid @ 500 lbs/A at 10 days and repeated
1; weeks later.
2. Preplant, castor pomace e 500 lbs/A at planting + 500
lbs. 5-5-3-2 at 4 weeks.
3. Preplant, 5-5-8-2 @ 500 lbs/A + 500 lbs/A at 4 weeks.
These results must be repeated, but it is interesting to note
that, in this case, liquid fertilizer was among the better treatments.
In other research, liquid materials have performed well on certain crops
in some seasons. \le feel that the liquid fertilizers will find a more
prominent place in vegetable production programs. However, considerably
more research and experience will be needed on these materials before we
can be more specific in our recommendations.
B. Sting Nlematode Control in Cabbage
Dr. H. L. Rhoades reported on a nematicide test on cabbage
in soil heavily infested with sting nematodes. The results are interesting
because they show that sting nematode control affected 'first cut" yield
to a greater degree than final total yield. Of the 16 treatments used, two
are selected to show these results.
Effect of Nematicides on nematode Populations and Cabbage Yield
Rate/ Sting Yield (crates/acre)
Treatment Acre ;Jematodes First Cut Total
Check 115 347 698
D-D 25 gals. broadcast 10 606 822
This kind of information is extremely important in light
of ever-pressing needs for uniformly maturing crops which lend them-
selves to once-over harvest by machines.
C. Cabbage Variety Trials.
Dr. J. 0. Strandberg tested 75 varieties of cabbage on
which he made observations on resistance to black speck and black rot,
maturity, head size, leaf color, head shape, interior quality and
Considerable resistance was noted to black speck--a non-
parasitic disease that seems to intensify in storage. Rating on a scale
of 0 (none) to 5 (severe), susceptibility to speck ranged from 0.3 for
a numbered hybrid to 3.7 for one of the standard hybrid varieties.
The same was true for black rot. Susceptibility ranged
from about 1.0 to as high as 5. Some of the varieties that combined
fair resistance to both are Saf-Gard, Round-up, and Rio-Verde. Several
numbered hybrids exhibited resistance which was as good or better than the
varieties named above. Rio-Verde was observed to be rather highly
susceptible to internal tip burn last year at Bunnell, Florida.
NOTE: Anyone wanting a copy of this cabbage variety
trial may request it from this office.
D. Looper Control on Cabbage
Dr. G. L. Greene reported on results of a study conducted
at Sanford which is part of a four-station project in Florida. He
stated "control of cabbage looper larvae is nearly impossible to obtain
using currently recommended materials, particularly when large, late
instar larvae are abundant." He further stated "the percentage of heads
unmarketable was extremely high indicating the weekly application
schedule was too long a treatment interval."
Dr. Greene and others are continuing work to find better
materials. His work points out that loopers must be killed shortly after
hatching or control becomes next to impossible.
Vegetable Crops Specialist