2007 Extension Research Report
Insect Management
EVALUATION OF SELECTED SYNTHETIC AND BIORATIONAL
INSECTICIDES FOR CONTROL OF CABBAGE LOOPER AND
IMPORTED CABBAGEWORM
Alton N. Sparks, Jr., University of Georgia Cooperative Extension, Department of Entomology
Tifton, GA 31794, asparks@uga.edu
treatments were tank mixed with Penetrator Plus
at 0.25% by volume.
Treatments were applied with a CO2
pressurized backpack sprayer (60 PSI) in a total
volume of 40 gpa with 3 hollow-cone nozzles per
row (one over-the-top; two on drops). Insecticide
application dates are indicated in Table 1.
Caterpillar densities in the test were
monitored with visual examination of plants. On
each sample date, five randomly selected plants in
each plot were visually examined for
lepidopterous larvae. Larvae were classified by
species (diamondback moth, cabbage looper,
imported cabbageworm), or classified as small if
they were too small for field identification, and
counted. Counts were recorded, and are reported,
as number of larvae per 5 plants.
As damage from caterpillars accumulated,
plots were visually inspected and the severity of
damage to the foliage was rated. Plots were rated
on a 0 to 6 scale as follows:
0 = no damage
1 = slight or minimal damage on less than
½ of the plants in the plot
2 = slight damage on greater than ½ of the
plants in the plot
3 = moderate damage on less than ½ of
the plants in the plot
4 = moderate damage on greater than ½ of
the plants in the plot
5 = severe damage on less than ½ of the
plants in the plot
6 = severe damage on more than ½ or the
plants in the plot
Half increments were used. “Slight” damage
would consist primarily of tiny holes in leaves or
Introduction
Caterpillars are the primary pests of
Brassica crops in Georgia. Numerous species can
be found on these crops, with the most frequent
species in south Georgia being the diamondback
moth, cabbage looper and imported cabbageworm.
As key pests of these crops, caterpillars can
require frequent insecticide applications and the
potential for insecticide resistance is always of
concern. Proper rotation of insecticides requires
multiple efficacious chemistries; thus, screening
of materials for activity against these pests is
needed. This test was conducted to evaluate
selected insecticides and insecticide combinations
against common caterpillar pests of Brassica
crops.
Material and Methods
A small plot trial was conducted at the
University of Georgia’s Horticulture Farm in
Tifton, Georgia. Collards were transplanted into
single rows on six foot beds. Experimental plots
measuring one row (assumed 36 in for treatment)
by 25 feet were arranged in a randomized
complete block design with four replications.
Treatments evaluated included BAS 320
I (2SC) at 16 oz/ac, alone, as a tank mix with
Mustang Max at 3.2 oz/ac, and in rotation with
Proclaim 5SG at 3.2 oz/ac. Additional synthetic
insecticides evaluated were Rimon 0.83EC at 12
oz/ac, Assail 30WDG at 4 oz/ac, and Proclaim
5SG at 3.2 oz (as the standard insecticide).
Biorational insecticide treatments evaluated were
Kryocide at 10 lb/ac and Kryocide at 10 lb/ac tank
mixed with Microthiol at 2 lb/ac. A non-treated
control was included for comparison. All
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‘windowpaning ’ typically associated with very
early instar larvae, with damage usually on one
leaf of a plant. “Moderate” damage may consist of
excessive windowpaning or presence of a few
larger holes in multiple leaves. Severe damage
consists of multiple large holes or large portions
of leaves consumed, generally with multiple
leaves damaged on a plant. A rating below 3
would likely meet commercial acceptance.
Data were analyzed using the PROC
ANOVA procedure of PC-SAS. Where significant
differences were detected (P<0.05), means were
separated with LSD (P=0.05).
significant reductions (as compared to the check)
on 3 of the 6 sample dates. Addition of Microthiol
to the Kryocide did not consistently aid control,
and in fact, significantly decreased control on two
sample dates. Assail provided no control of looper
larvae.
Damage rating data (Table 3) show trends
similar to the data for looper larvae. All
treatments, with the exception of Assail,
consistently reduced damage ratings, as compared
to the check. The first two damage ratings show
similar results. Both Kryocide treatments provided
some reduction in damage, but this reduction
would not likely meet commercial standards. BAS
320 applied alone provided ‘borderline’ control,
with an average rating slightly above 2 (light
damage throughout the plot). The Rimon,
Proclaim, BAS 320+Mustang Max and the
BAS/Proclaim rotation provided the greatest
suppression of damage, followed closely by BAS
320 alone. Damage suppression was obvious
through 14 Dec. (23 days after the last
application). It is assumed that this rating actually
reflects differential control in late-November, with
little additional damage in December as some of
the treatments are known to provide relatively
short residual control.
Results and Discussion
Cabbage loopers were the predominant
species in this test and likely caused the vast
majority of the damage. Thus, only the looper data
is presented (Table 2). On the first sample date (3
days after the initial application), no significant
differences were detected, indicating no obvious
knockdown activity with any of the treatments.
Thereafter, Rimon, Proclaim and all of the BAS
320 treatments provided significant reductions in
looper densities, with no significant differences
among these treatments (although BAS 320
applied alone frequently had the highest numeric
counts among these treatments). Kryocide did
provide some suppression of looper larvae, with
Table 1. Application dates for insecticide treatments, efficacy study in collards, UGA Horticulture
Farm, Tifton, GA, 2006.
Date
Treatments applied
Insecticide applied in the
BAS 320/Proclaim rotation
20 Oct.
All treatments
BAS 320 I
24 Oct.
Both Kryocide treatments
25 Oct.
All except both Kryocide treatments
28 Oct.
Both Kryocide treatments
8 Nov.
All treatments
Proclaim
BAS 320 I
13 Nov.
All treatments
Proclaim
The Krycoide and Kryocide+Microthiol treatments were re-applied on 24 Oct. because of a rain event on
23 Oct.
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Table 2. Collards Efficacy Trial, Horticulture Farm, UGA Tifton Campus, Tifton, Georgia, 2006.
Looper larvae per 5 plants
Treatment
23 Oct.
27 Oct.
30 Oct.
6 Nov.
13 Nov.
21 Nov.
Check
6.75 a
11.25 ab
10.50 b
6.75 a
8.25 a
13.25 a
Assail
7.50 a
14.25 a
16.50 a
5.50 ab
8.25 a
13.25 a
Kryocide
5.25 a
5.75 cd
3.00 c
3.50 abc
3.50 b
10.75 a
Kry.+Micro.
5.75 a
8.50 bc
8.00 b
5.25 ab
1.75 b
6.75 b
BAS 320 I
5.75 a
3.50 de
1.25 c
1.00 bc
2.00 b
0.75 c
BAS + MM
2.25 a
0.00 e
0.75 c
0.00 c
1.00 b
0.75 c
BAS / Proc.
3.25 a
4.00 cde
0.50 c
0.25 c
0.25 b
0.00 c
Rimon
2.50 a
2.00 de
0.25 c
1.75 bc
0.75 b
0.50 c
Proclaim
4.00 a
0.50 e
0.25 c
0.50 c
0.00 b
1.25 c
Numbers within columns followed by the same letter are not significantly different (LSD; P=0.05).
Table 3. Collards Efficacy Trial, Horticulture Farm, UGA Tifton Campus, Tifton, Georgia, 2006.
Plot Ratings (0 to 6)
Treatment
10 Nov.
16 Nov.
22 Nov.
14 Dec.
Check
5.00 a
5.63 a
5.75 a
6.00 a
Assail
4.63 a
4.75 ab
5.00 a
5.13 b
Kryocide
3.38 b
4.00 b
3.63 b
5.00 b
Kry.+Micro.
3.63 b
4.13 b
3.88 b
4.88 b
BAS 320 I
2.13 c
2.13 c
2.50 c
2.00 c
BAS + MM
0.50 e
0.75 d
0.63 d
1.00 d
BAS / Proc.
1.38 cd
1.88 c
2.00 c
1.13 d
Rimon
1.50 c
1.75 c
0.88 d
1.00 d
Proclaim
0.63 de
0.75 d
1.00 d
Numbers within columns followed by the same letter are not significantly different
(LSD; P=0.05).
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1.00 d