RESIDUAL CONTROL OF CATERPILLAR PESTS WITH FOLIAR
APPLIED CORAGEN AND SYNAPSE WITH AND WITHOUT
DYNEAMIC
Alton N. Sparks, Jr., Extension Entomologist
University of Georgia, Tifton Campus
P.O. Box 748
Tifton, GA 31794
asparks@uga.edu
Introduction
Coragen and Synapse have shown excellent control of caterpillar pests of cole
crops when applied as foliar applications. Some experiments suggest that the initial
activity and residual control of these products may be enhanced with adjuvants that aid in
penetration of the leaf surface. This test was conducted to evaluate the effects of a
penetrating surfactant on the efficacy and residual activity of these two insecticides.
HGW86 is an insecticide of similar chemistry being developed. It was included in this
test for comparison.
Materials and Methods
A small plot trial was in collards transplanted at the University of Georgia’s
Horticulture Farm in Tfiton, Georgia. Experimental plots were on row (36 inches) by 22
feet. The test was conducted as a randomized complete block with four replications.
Insecticides evaluated were Coragen 1.67SC (5 oz/ac), Synapse 24WDG (3 oz/ac), and
HGW86 10SE (13.5 oz/ac). Coragen and Synapse were applied with and without addition
of DyneAmic (0.5% v/v). HGW86 was applied with DyneAmic, and the water for this
treatment was buffered (Ph below 7) prior to mixing. Anon-treated check was included
for comparison. All insecticide treatments (with and without adjuvant) were applied on a
7 and 14 day schedule. Plots on a 7 day schedule were treated four times (2, 9, 15 and 23
July, 2009) and those on the 14 day schedule were treated twice (2 and 15 July, 20090).
Applications were made with a CO2 pressurized backpack sprayer (60 psi) in 40 GPA,
with three hollow-cone nozzles per row (one over the top, 2 on drops).
Five randomly selected plants in each plot were visually searched on each sample
date for caterpillars. All caterpillars were identified and counted. For damage ratings, all
plants in each plot were visually observed for feeding damage. All plants with moderate
or severe damage (obvious holes through leaves) were counted. Data were analyzed with
the PROC ANOVA procedure of PC-SAS. Where significant differences were detected
(P<0.05), means were separated with LSD (P=0.05).
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Results and Discussion
Both the caterpillar counts and the damage counts show similar trends. The 7 day
application schedule provided better control than the 14 day schedule for all insecticide
treatment. Caterpillar counts and damage showed good control from 4 to 8 days after an
application (irrespective of timing) and showed a numerical (and often statistical)
increase at 12 or 13 days (or more) after an application. Statistical suppression of insects
and damage was seen for longer periods (up to 20 days), but increases were obvious by
12 to 14 days. Addition of DyneAmic did not consistently affect efficacy or residual
activity of either product.
While some research has shown dramatic increase in efficacy with addition of a
penetrating surfactant to both Coragen and Synapse, that did not occur in this test. The
surfactant did not consistently effect initial efficacy or residual control. Residual control
of these products when applied as a foliar application has been reported as 10 to 14 days.
In this test, residual control appeared to be within that range, but less than 14 days.
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Table 1. Coragen/Synapse surfactant test, collards, Horticulture Farm, 2009.
Treatment
Application
Number of caterpillars (all species) per 5 plants
frequency
8 July
14 July
22 July
28 July
31 July
4 Aug
Days after last treatment (7 & 14 day schedule)
6&6
5 & 12
7&7
5 & 13
8 & 16
12 & 20
0 Check
3.50 a
1.75 a
3.50 a
7.75 a
15.25 a
13.75 a
21 Coragen
14 days
0.50 b
1.50 ab
0.50 b
2.00 bc
8.50 bc
9.25 b
22 Coragen+Dyneamic
14 days
0.00 b
0.25 c
0.00 b
3.00 bc
3.75 cd
4.00 cde
23 Synapse
14 days
0.50 b
1.75 a
0.50 b
2.50 bc
5.50 bcd
5.75 bcd
24 Synapse+Dyneamic
14 days
0.00 b
0.75 bc
0.00 b
5.00 ab
10.75 ab
7.25 bc
25 Hgw86+Dyneamic
14 days
0.00 b
0.75 bc
0.00 b
3.00 bc
5.50 bcd
8.00 bc
1 Coragen
7 days
0.50 b
0.25 c
0.25 b
1.00 c
2.00 d
2.00 de
2 Coragen+Dyneamic
7 days
0.00 b
0.00 c
0.00 b
0.00 c
0.00 d
1.50 e
3 Synapse
7 days
0.25 b
0.25 c
0.25 b
1.50 bc
2.50 cd
4.25 cde
4 Synapse+Dyneamic
7 days
0.00 b
0.00 c
0.00 b
0.00 c
1.25 d
1.75 de
5 Hgw86+Dyneamic
7 days
0.00 b
0.00 c
0.00 b
0.00 c
0.25 d
1.00 e
6 Aug
14 & 22
4.75 a
5.00 a
2.25 abcd
4.00 ab
2.50 abcd
3.50 abc
2.25 abcd
0.50 d
1.50 bcd
1.25 bcd
1.00 cd
50
Table 2. Coragen/Synapse surfactant test, collards, Horticulture Farm, 2009.
Treatment
Application
Number of plants per plot with moderate or severe feeding damage
frequency
27 July
31 July
4 Aug
7 Aug
14 Aug
Days after last treatment (7 & 14 day schedule)
4 & 13
8 & 17
12 & 21
15 & 24
22 & 31
0 Check
7.75 a
8.25 a
9.25 a
9.50 a
9.50 a
21 Coragen
14 days
4.50 b
5.00 b
8.75 a
10.00 a
9.75 a
22 Coragen+Dyneamic
14 days
2.75 c
3.25 b
7.25 a
8.00 ab
8.75 a
23 Synapse
14 days
3.00 bc
4.25 b
8.00 a
8.50 a
9.00 a
24 Synapse+Dyneamic
14 days
2.50 c
4.25 b
7.75 a
9.50 a
10.00 a
25 Hgw86+Dyneamic
14 days
1.75 cd
4.50 b
9.00 a
9.75 a
9.75 a
1 Coragen
7 days
0.50 de
0.25 c
2.25 b
5.50 c
8.25 a
2 Coragen+Dyneamic
7 days
0.25 de
0.00 c
1.00 bc
2.50 de
7.75 a
3 Synapse
7 days
0.25 de
0.50 c
2.50 b
6.25 bc
8.25 a
4 Synapse+Dyneamic
7 days
0.00 e
0.25 c
2.25 b
4.50 cd
8.50 a
5 Hgw86+Dyneamic
7 days
0.00 e
0.00 c
0.00 c
2.00 e
7.00 a
51