EVALUATION OF EXPERIMENTAL INSECTICIDE TREATMENTS IN
COLLARD
David G. Riley and Alton “Stormy” Sparks Jr.
University of Georgia, Tifton Campus
Department of Entomology
Tifton, GA 31793
dgr@uga.edu
Introduction
Collards, Brassica oleracea (L.) Acephala group (in this test`Top Bunch'), is the
other main Brassica crop, next to cabbage, in Georgia. It is faced with similar multiple
pests that attack the leaves, namely, diamondback moth (DBM); Plutella xyllostella,
cabbage looper (CL); Trichoplusia ni, and imported cabbage worm (ICW); Pieris rapae.
This test evaluated new number compounds from Syngenta, compared to a standard
pyrethroid insecticide. The use of new chemistries and product rotations are critical for
managing insecticide resistance in DBM.
Materials and Methods
Collards was transplanted into 2 rows per 6-ft beds on 6 March 2007 and
maintained with standard cultural practices at the Lang Farm, Georgia Coastal Plain
Experiment Station at Tifton. A total of 500 lbs of 10-10-10 and 300 lbs of 34-0-0 were
applied to Tift pebbly clay loam field plots and irrigation was applied regularly with an
overhead sprinkler system. Scouting was conducted weekly from 3 April using two
samples of 6 plants per plot. Foliar applications of insecticides were made approximately
weekly from 6 April to 18 May. Plant tops were harvested from 10 ft of the center of the
plot row on 7 and 24 May and plant tops were weighed and categorized as 0=not
damaged, 1=slightly damage, 2=moderately damaged, 3=severely damaged by worms or
contaminated by whitefly nymphs. Damage ratings >1 were not marketable collards. Data
was analyzed using GLM and LSD tests for separation of means (SAS Institute 1990).
Results and Discussion
All of the treatments except for the Warrior treatment provided excellent control
of lepipodteran pests across all species encountered. Even Warrior provided significant
control of diamondback moth, but started to lose efficacy by the last sample date. The
best treatments in terms of control of Lepidoptera larvae, reduction in damage, and
increased marketable yield of collards were all rates of A15397 50/100SC and all rates of
A15365 250SC except the lowest rate of 30 grams ai/ha which experienced a significant
increase in damage and decrease in marketable yield compared to the high rates. All pest
species of Lepidoptera encountered in this test were controlled by A15397 50/100SC and
the higher rates of A15365 250SC which resulted in significant increases in marketable
yield.
25
Diamondback moth
large larva
4/30/07
1.3 a
Diamondback moth
pupa
4/30/07
3.0 a
Diamondback moth
4/30/07
Leps total
4/30/07
Cabbage
Looper
5/11/07
Diamondback moth
5/11/07
Treatment - rate per acre
1. Untreated Check
Diamondback moth
small larva
4/30/07
2.5 a
6.8 a
7.5 a
3.3 a
9.5 a
2. A15397 50/100SC 45 gai/ha
0.0 c
0.5 abc
0.3 c
0.8 cde
2.0 bc
0.0 b
2.5 cd
3. A15397 50/100SC 60 gai/ha
0.3 bc
0.0 c
0.3 c
0.5 de
1.1 bc
0.3 b
3.0 bcd
4. A15397 50/100SC 75 gai/ha
0.0 c
0.3 bc
0.0 c
0.3 e
0.5 c
0.5 b
3.8 bc
5. A15397 50/100SC 90 gai/ha
0.5 bc
0.8 abc
0.5 bc
1.8 bcd
2.0 bc
0.3 b
1.5 d
6. A15365 250SC 30 gai/ha
0.8 bc
0.5 abc
0.3 c
1.5 bcde
1.5 bc
0.8 b
3.3 bc
7. A15365 250SC 40 gai/ha
0.3 bc
1.0 ab
0.5 bc
1.8 bcd
1.8 bc
1.0 b
3.0 bcd
8. A15365 250SC 50 gai/ha
1.0 b
0.3 bc
0.8 bc
2.0 bc
2.3 bc
0.0 b
3.5 bc
9. A15365 250SC 60 gai/ha
0.3 bc
0.8 abc
1.5 b
2.5 b
2.8 b
0.5 b
2.5 cd
10. Warrior/Zeon 1CS 28 gai/ha
0.3 bc
0.5 abc
0.5 bc
1.3 bcde
3.0 b
1.3 b
4.3 b
* Means within columns followed by the same letter are not significantly different (LSD, P<0.05).
26
Overall
Diamondback moth
3.5 a
Imported
cabbage
worm
1.2 a
Leps total
Overall
1. Untreated Check
Overall
Cabbage
looper
0.58 a
5.3 a
First
Damage
rating
1.9 a
Overall
Damage
rating
2.2 a
Marketable
Weight of
Collards
11 c
2. A15397 50/100SC 45 gai/ha
0.04 b
1.2 b
0.4 b
1.6 b
0.6 d
1.2 d
35 ab
3. A15397 50/100SC 60 gai/ha
0.17 b
1.7 b
0.2 b
2.0 b
0.7 cd
1.3 cd
28 ab
4. A15397 50/100SC 75 gai/ha
0.13 b
1.9 b
0.3 b
2.4 b
0.6 d
1.3 cd
29 ab
5. A15397 50/100SC 90 gai/ha
0.08 b
1.2 b
0.5 ab
1.8 b
0.8 cd
1.2 d
39 a
6. A15365 250SC 30 gai/ha
0.13 b
1.5 b
0.5 b
2.1 b
0.9 bc
1.5 bc
21 bc
7. A15365 250SC 40 gai/ha
0.25 ab
1.4 b
0.3 b
1.9 b
0.7 cd
1.3 cd
36 ab
8. A15365 250SC 50 gai/ha
0.08 b
1.6 b
0.5 b
2.2 b
0.7 cd
1.1 d
41 a
9. A15365 250SC 60 gai/ha
0.08 b
1.5 b
0.5 b
2.1 b
0.7 cd
1.1 d
37 a
10. Warrior/Zeon 1CS 28 gai/ha
0.38 ab
1.9 b
0.7 ab
3.0 b
1.1 b
1.8 b
20 bc
Treatment - rate per acre
* Seasonal means within columns followed by the same letter are not significantly different (LSD, P<0.05).
27