AGRICULTURAL RESEARC1-CENTEr ,
Hastings, Flor da JF' i --"
t I BRARY -
Mimeo Report POL-71-8 August 1971
WEED CONTROL TRIALS ON CABBAGE AT HA INGS, FiORfb i 6-71
J. R. Shumaker, Asst. Ho ticulturist
VMETHODS: -- Of Flor ia
Twelve chemical treatments were compared with a nontreated control for effectiveness
of weed control in cabbage during the 1970-71 season at Hastings, Florida. Treat-
ments were replicated 4 times in a randomized block field design. The soil used
for these tests consisted of a mixture of Bladen sandy loam, Leon fine sand, and
hardpan which had been broken during land leveling. This soil contained 1 1/2 to
2% organic matter. A 6-8-8 fertilizer was banded on each side of the row at the
rate of 1800 pounds per acre prior to transplanting. Plants of the cultivar,
Head Start, were machine transplanted approximately 12 inches apart in the rows on
November 30. Each plot was 4 rows by 25 feet long with 40 inches between rows.
Due to extremely dry soil conditions, application of chemicals was delayed until
after cabbage was cultivated on December 21. All chemicals were broadcast over
the cabbage via 4-row sprayer -- 40 gpa; 30 psi -- with 2 flat-tip nozzles per row.
Alachlor and nitrofen were superimposed on previously treated DCPA plots to complete
these combinations. Combinations of CDAA + CDEC and alachlor + CDEC were tank
mixed. All plots were watered at the approximate rate of 1000 gpa directed in the
rows after the last treatment was applied. Recommended insect and disease control
practices were followed. Subsurface irrigation and supplemental side dressings of
fertilizer were provided as needed. Data for each variable were collected from the
two inside rows of the 4-row plots. Weed control was rated by a scale of 1 = no
control to 10 = complete control. All control plots were given a rating of 1 and
treated plots were rated relative to the control plot in each replication. Ratings
represent the average value of data taken independently by two workers. A rating
of 7 or higher was considered commercially acceptable. A once-over cabbage harvest
and weed ratings were taken on March 1 and 3 respectively.
Above average temperatures and below average rainfalls were recorded from trans-
planting until after chemicals were applied. However, unseasonably cold and wet
conditions prevailed during the remaining season. On January 21, a hard freeze,
170 F, was quickly followed with a high temperature for that date of 610 F. Severe
reductions in quality, yields, and size of cabbage coupled with a delay in weed
pressure were observed and attributed to this freeze and to the persistently low
temperature during early winter. Rains recorded over the duration of these trials
follow: December 17 0.33", December 29 0.67", December 30 0.03", December 31 -
0.65", January 4 0.21", January 5 0.37", January 6 0.11", January 7 = 0.70",
January 8 0.03", January 11 0.48", January 18 0.07", February 1 0.81",
February 8 3.76:, February 9 0.29", February 13 0.08", February 23 0.13",
and February 26 0.59" for a total of 9.31". Of this total, only 0.33" of rain
were recorded from transplanting to application of chemicals.
Chemical injury to the crop was not observed in these trials. Weed pressures,
while not great until late season, were virtually entirely due to broadleaf
species. Predominate weeds were the seedling docks (Rumex spp.), chickweed
(Stellaria media), and primrose (Oenothera laciniata). Of minor importance
were cudweed (Gnaphalium peregrinum) and the watercresses, (Rorippa spp.).
The most numerous and troublesome weed was dock, which constituted approximately
50% of the total weed pressures, while chickweed and primrose (and other weeds)
each constituted 25%. Significantly greater weed control was observed in all
chemically treated plots than was observed in the control (Table 1). Alachlor
at 3.0 AI/A (lb.), nitralin at 1.0 and 0.5 AI/A (lb.), alachlor + CDEC at
1.5 + 3.0 AI/A (lb.), DCPA + alachlor at 6.0 + 1.5 AI/A (lb.), and DCPA +
nitrofen at 6.0 + 4.0 AI/A (lb.) were effective in controlling dock, chickweed,
and primrose. Both the 10.5 and 6.0 AI/A (lb.) rates of DCPA were very
effective in controlling dock and chickweed, but they were slightly less
effective in controlling primrose. Alachlor at 1.5 AI/A (lb.) controlled dock
and primrose effectively but was less effective in controlling chickweed.
Nitrofen at 4.0 AI/A (lb.) was effective in controlling dock and primrose
but was not effective in controlling chickweed. CDEC and CDAA at 3.0 + 3.0
AI/A (lb.) and CDEC at 6.0 AI/A (lb.) were effective in controlling chickweed
and primrose but were not effective in controlling dock. There was no
significant response to differences among treatments for yield, head size, or
number of heads (Table 2). However, all chemical treatments did produce greater
yields and larger heads than the control.
DCPA (Dactha ), CDEC (Vegade ), CDAA (Rando )) and a combination of CDEC
and CDAA are approved for use on cabbage under local conditions. They are
recommended and have been used cuite extensively by local growers. Nitralin
(Planavit ), and nitrofen (Tok ) are also approved for use on cabbage but
have not been thoroughly tested under local conditions and, therefore, can only
be suggested for trial purposes. At this date, alachlor (LassdO) is not
approved for use on cabbage. Growers are urged to proceed with caution when
applying herbicides. Always read the container label and check for recent
changes regarding crop, rate, time schedule, soil type, and method of application
approved for use.
POL-71-8 Page 2
Table 1. Ratings of 1970-71 weed control trials on cabbage at Hastings, Florida.
Weed Control Ratings2/
Herbicide Broadcast Primrose./
Common Rate and Other
Name Trade NameV Lb. AI/Al/ Dock Chickweed Weeds
Alachlor Lasso hE 3.0 9.4 8.5 9.5
DCPA Dacthal 75W 6.0 9.4 8.9 7.5
DCPA Dacthal 75W 10.5 9.3 8.9 7.8
Alachlor + Lasso 4E + 1.5 + 3.0 9.3 8.5 9.3
CDEC4/ Vegadex 4E
DCPA + Dacthal 75W + 6.0 + 1.5 9.3 9.0 8.6
Alachlor./ Lasso 4E
Alachlor Lasso hE 1.5 8.6 6.9 9.3
DCPA + Dacthal 75W + 6.0 + 4.0 8.6 8.1 8.9
NitrofenS/ Tok 50W
Nitrofen Tok 50W 4.0 8.5 3.3 8.4
Nitralin Planavin hE 1.0 8.4 8.9 8.1
Nitralin Planavin hE 0.5 7.5 7.4 8.3
CDEC Vegadex 4E 6.0 5.5 9.0 9.8
CDAA + Randox hE + 3.0 + 3.0 4.5 8.5 9.1
CDEC4/ Vegadex 4E
Control -- 1.0 1.0 1.0
LSD .05 1.82 1.70 1.37
Pounds of active ingredient per acre.
Scale 1-10; 1 no control, 10 complete control, 7 acceptable.
Primrose 95% of this group, others include cudweed, watercress and
POL-71-8 Page 3
Table 2. Effect of herbicides on cabbage yield, size, and number of heads --
Hastings, Florida, 1970-T1.
Herbicide Broadcast Head
Common Rate Yield Size No. Heads
Name Trade NamF-J Lb. AI/A-/ Cwt/A Lb. Per Plot2/
Alachlor Lasso 4E 1.5 199 1.90 40.0
Nitralin Planavin 4E 1.0 197 1.94 38.8
DCPA Dacthal 75W 10.5 195 1.88 39.8
Nitrofen Tok 50W 4.0 193 1.96 37.5
DCPA Dacthal 75W 6.0 190 1.96 37.0
Alachlor + Lasso 4E + 1.5 + 3.0 187 1.95 36.7
CDEC2/ Vegadex 4E
DCPA + Dacthal 75W + 6.0 + 1.5 178 1.96 34.8
Alachlor/ Lasso 4E
DCPA + Dacthal 75W + 6.0 + 4.0 177 1.89 35.8
Nitrofenk4/ Tok 50W
Nitralin Planavin 4E 0.5 176 1.86 36.3
Alachlor Lasso 4E 3.0 173 1.86 35.5
CDAA + Randox 4E + 3.0 + 3.0 170 1.88 34.5
CDEC3/ Vegadex 4E
CDEC Vegadex hE 6.0 168 1.82 35.3
Control -- 167 1.79 35.8
1/ Pounds of active ingredient per acre.
2/ Based on 50 transplants per plot.
3/ Tank mix.
4/ Separate applications.
POL-71-8 Page 4