2007 Extension Research Report
Insect Management
EVALUATING FOLIAR INSECTICIDES FOR CONTROLOF THRIPS
AND OTHER INSECTS ON SNAP BEANS
Robert M. McPherson, University of Georgia, Dept. of Entomology, Tifton, Georgia 31793,
pherson@uga.edu
Introduction
Insect pests are an annual threat to
Georgia’s snap bean crop, causing over $2.3
million in control costs and crop damage in 2004
(UGA, CAES, Misc. Pub. 106, Summary of
losses from insect damage and cost of control in
Georgia, 2004). Thrips, several foliage and
bloom species, are one of the major insect pests
of the crop, causing premature defoliation,
bronzing or a silvery cast on the leaves, and
scarring on the pods. High thrips populations
can result in stunted plant growth. This test was
conducted to evaluate the effectiveness of
selected foliar insecticides in suppressing thrips
populations in snap bean blooms and other
suppressing insect species present on the snap
bean foliage.
taken down a single row from each plot, placed
into a clear plastic bag, labeled, and returned to
the lab where it was frozen and then counted on
a later date. All thrips, both immatures and
adults, and minute pirate bags (insect predators
of thrips) were recorded from each vial on each
sampling date. Random adult thrips were
obtained from the vial samples from each date
and sent to the UGA Thrips Diagnostics Lab
where they were mounted on microscope slides
and identified to species by Mr. Stan Diffie. All
arthropod pests in each sweep net sample also
were identified and counted. All insect count
data were analyzed using the ANOVA
procedure of SAS (P<0.05) and significant mean
differences were separated using the WallerDuncan K-ratio t-test, (P=0.05).
Materials and Methods
Replicated field plots were established
at the University of Georgia Lang Research
Farm in Tift County Georgia. “Carlo” snap
beans were planted on 12 April 2006. On 30
May, plots 4 rows (3-ft row spacing) x 70 feet
were established and eight insecticides
treatments were randomly arranged in each of
three replications in a randomized complete
block design. There were two untreated border
rows on each side of each plot.
On 30 May, each insecticide was
applied using a CO2 – powered backpack
sprayer delivering 21.3 gpa at 40 psi through
two 8002 flat fan nozzles per row. An untreated
control was also included. All plots were
sampled prior to treatment (Pre-t) and at 1, 3, 7,
and 10 days after treatment (DAT). On each
sampling date, 10 blooms were randomly
collected from each plot, placed into a vial,
containing 70% ethanol, labeled, and returned to
the laboratory for observations. Also on each
date except 1 DAT, a 25 – sweep sample was
Results and Discussion
Thrips adults per 10 blooms were
significantly lower in some treatments than in
the untreated control at 1 DAT and all
treatments were lower than the control at 3 DAT
(Table 1). At 7 and 10 DAT, adult thrips
populations were not different between any of
the treatments. Of the adult thrips identified,
10.3% were the western flower thrips,
Frankliniella occidentalis, and 89.7% were
flower thips, F. tritici plus f. bispinosa
combined.
Similar results were noted for
immature thrips and total thrips (adults plus
immatures) densities in the blooms, except that
Lannate was not different than the untreated
plots at 3 DAT (Tables 2 and 3). There were no
differences in minute pirate bugs between the
treated and untreated plots on any sampling date
(Table 4). However, the Asana treatment had
more pirate bugs than in the Mustang Max and
Orthene treatments at 7 DAT (Table 4). In the
sweep net samples, there were no treatment
differences in threecornered alfalfa hoppers
131
these products suppressed thrips for up to 3
DAT; however, populations were similar in all
treatments on 7 to 10 DAT. Minute pirate bug,
threecornered alfalfa hopper and stink bug
densities were affected very little by these
insecticides;
however
populations
were
relatively low in all plots, including the
untreated control, on all the sampling dates
during this study.
(Table 5) and minute pirate bugs (Table 6) on
any of the sampling dates. Stink bugs were
more numerous in the Tracer plots than in five
of the other insecticide treatments at 3 DAT, and
more numerous in the control plots than in all
the treated plots (except Asana) at 10 DAT
(Table 7). Arthropod predators (bigeyed bugs,
nabids and spiders, combined) were lower in
most of the treated plots than in the Lannate and
Orthene plots at 3 DAT, but no other treatment
differences were noted (Table 8).
All of the seven insecticides evaluated
in this trial are labeled for snap beans, except
that Tracer 4 SC is the labeled formulation of
spinosad that is used in row crops while SpinTor
2 SC is actually the formulation of spinosad
labeled for use in vegetable pest control. All of
Acknowledgments
The author expresses his gratitude to
Neal Roberson, Del Taylor and Stan Diffie for
technical support and to the University of
Georgia Agricultural Experiment Stations for
financial support.
Table 1. Control of adult thrips on snap bean blooms treated with selected foliar insecticides, Tift
County, Georgia, 2006.
Insecticide and lbs.
Adult thrips per 10 blooms
AI / acre
Pre–t
1 DAT
3 DAT
7 DAT
10 DAT
Capture 2EC
Orthene 97PE
Warrior 1CS
Lannate 2LV
Mustang Max 0.8EC
Tracer 4SC
Asana 0.66EC
Untreated
0.0625
0.73
0.025
0.6
0.022
0.078
0.04
F value
Degrees of freedom
P value
109.5a
90.5a
101.5a
105.0a
107.5a
132.5a
98.5a
108.5a
17.3abc
23.7ab
11.3bc
4.0c
7.7c
17.7abc
13.0abc
27.7a
3.0b
2.3b
1.7b
1.3b
2.7b
3.0b
2.0b
8.7a
3.3a
2.7a
3.3a
3.3a
1.7a
2.0a
4.3a
3.3a
6.7a
6.0a
7.0a
9.7a
3.0a
3.7a
5.0a
4.3a
0.26
7,14
0.951
3.38
7,14
0.025
2.98
7,14
0.038
0.62
7,14
0.731
0.83
7,14
0.582
Carlo snap beans planted on 12 April. Plots 4 rows x 70 ft with 2 row untreated border, RCBD with 3
reps. Treatments applied with a CO2–powered backpack sprayer on 30 May. Column means with the
same letter are not significantly different, Waller-Duncun K-ratio t-test (P=0.05).
132
Table 2. Control of immature thrips on snap bean blooms treated with selective foliar insecticides,
Tift County, GA, 2006.
Insecticide and lbs.
Immature thrips per 10 blooms
AI / acre
Pre–t
1 DAT
3 DAT
7 DAT
10 DAT
Capture 2EC
Orthene 97PE
Warrior 1CS
Lannate 2.4LV
Mustang Max 0.8EC
Tracer 4SC
Asana 0.66EC
Untreated
0.0625
0.73
0.025
0.6
0.022
0.078
0.04
F value
Degrees of freedom
P value
30.5a
29.0a
40.0a
34.0a
20.5a
39.0a
14.0a
43.0a
29.3abc
25.0bc
25.7bc
17.0c
17.7c
46.0a
41.3ab
42.7ab
28.0b
16.3b
26.7b
39.3ab
23.3b
25.0b
20.7b
54.0a
51.0a
73.7a
59.3a
75.0a
64.0a
88.0a
64.0a
74.0a
40.3a
36.3a
38.7a
35.3a
32.0a
28.3a
29.0a
27.7a
0.85
7,14
0.584
3.93
7,14
0.014
3.09
7,14
0.034
1.38
7,14
0.286
0.76
7,14
0.631
Carlo snap beans planted on 12 April. Plots 4 rows x 70 ft with 2 row untreated border, RCBD with 3
reps. Treatments applied with a CO2–powered backpack sprayer on 30 May. Column means with the
same letter are not significantly different, Waller-Duncun K-ratio t-test (P=0.05).
Table 3. Control of thrips (adults & immatures) on snap bean blooms treated with selective foliar
insecticides, Tift County, GA, 2006.
Insecticide and lbs.
Thrips per 10 blooms
AI / acre
Pre–t
1 DAT
3 DAT
7 DAT
10 DAT
Capture 2EC
Orthene 97PE
Warrior 1CS
Lannate 2.4LV
Mustang Max 0.8EC
Tracer 4SC
Asana 0.66EC
Untreated
0.0625
0.73
0.025
0.6
0.022
0.078
0.04
F value
Degrees of freedom
P value
140.0a
119.5a
141.5a
139.0a
128.0a
171.5a
112.5a
151.5a
46.7abcd
48.7abc
37.0bcd
21.0d
25.3cd
63.7ab
54.3ab
70.3a
31.0b
18.7b
28.3b
40.7ab
26.0b
28.0b
22.7b
62.7a
54.3b
76.3ab
62.7ab
78.3ab
65.7ab
90.0a
68.3ab
77.3ab
47.0a
42.3a
45.7a
45.0a
35.0a
32.0a
34.0a
32.0a
0.39
7,14
0.884
4.46
7,14
0.008
3.43
7,14
0.023
1.22
7,14
0.355
0.95
7,14
0.502
Carlo snap beans planted on 12 April. Plots 4 rows x 70 ft with 2 row untreated border, RCBD with 3
reps. Treatments applied with a CO2–powered backpack sprayer on 30 May. Column means with the
same letter are not significantly different, Waller-Duncun K-ratio t-test (P=0.05).
133
Table 4. Control of minute pirate bugs on snap bean blooms treated with selective foliar
insecticides, Tift County, GA, 2006
Insecticide and lbs.
Minute pirate bugs per 10 blooms
AI / acre
Pre–t
1 DAT
3 DAT
7 DAT
10 DAT
Capture 2EC
Orthene 97PE
Warrior 1CS
Lannate 2.4LV
Mustang Max 0.8EC
Tracer 4SC
Asana 0.66EC
Untreated
0.0625
0.73
0.025
0.6
0.022
0.078
0.04
0.5a
0.5a
0.5a
0.5a
0.5a
0.5a
1.0a
1.0a
0.3a
0.7a
0.3a
1.0a
0.3a
1.3a
0.0a
1.3a
1.0a
0.0a
0.3a
0.7a
0.3a
0.3a
0.3a
0.3a
1.7ab
0.3bc
1.7ab
0.7abc
0.0c
1.7ab
2.0a
0.7abc
0.3a
1.0a
0.7a
0.0a
0.3a
0.3a
1.3a
1.0a
F value
Degrees of freedom
P value
0.11
7,14
0.995
0.80
7,14
0.604
0.53
7,14
0.797
2.65
7,14
0.056
1.36
7,14
0.296
Carlo snap beans planted on 12 April. Plots 4 rows x 70 ft with 2 row untreated border, RCBD with 3
reps. Treatments applied with a CO2–powered backpack sprayer on 30 May. Column means with the
same letter are not significantly different, Waller-Duncun K-ratio t-test (P=0.05).
Table 5. Control of threecornered alfalfa hoppers on snap beans treated with selected foliar
insecticides, Tift County, GA, 2006.
Insecticide and
Threecornered alfalfa hoppers per 25 sweeps
lbs. AI/acre
Pre-t
3 DAT
7 DAT
10 DAT
Capture 2EC
0.0625
Orthene 97PE
0.73
Warrior 1CS
0.025
Lannate 2.4LV
0.6
Mustang Max 0.8EC 0.022
Tracer 4SC
0.078
Asana 0.66EC
0.04
Untreated
F value
Degrees of freedom
P value
2.0a
0.7a
0.0a
1.0a
2.0a
1.0a
0.7a
1.3a
0.0a
0.7a
0.0a
0.0a
0.0a
0.3a
0.0a
0.3a
0.7a
0.3a
0.3a
0.3a
1.5a
0.5a
0.7a
0.3a
0.3a
1.3a
0.7a
0.3a
1.0a
1.0a
0.3a
0.0a
0.79
7,14
0.607
1.39
7,14
0.283
0.50
7,14
0.822
1.54
7,14
0.233
Carlo snap beans planted on 12 April. Plots 4 rows x 70 ft with 2 row untreated border, RCBD with 3
reps. Treatments applied with a CO2-powered backpack sprayer on 30 May. Column means with the
same letter are not significantly different, Waller-Duncan K-ratio t-test (P=0.05).
134
Table 6. Control of minute pirate bugs on snap beans treated with selected foliar insecticides, Tift
County, GA, 2006.
Insecticide and
Pirate bugs per 25 sweeps
lbs. AI/acre
Pre-t
3 DAT
7 DAT
10 DAT
Capture 2EC
0.0625
Orthene 97PE
0.73
Warrior 1CS
0.025
Lannate 2.4LV
0.6
Mustang Max 0.8EC 0.022
Tracer 4SC
0.078
Asana 0.66EC
0.04
Untreated
F value
Degrees of freedom
P value
2.0a
2.3a
3.0a
2.7a
2.0a
3.0a
3.3a
2.7a
0.3a
0.3a
0.0a
0.3a
0.3a
1.7a
1.0a
0.3a
0.3a
0.3a
0.0a
0.0a
0.0a
1.0a
0.7a
0.7a
1.0a
0.7a
1.3a
0.3a
1.0a
0.3a
1.7a
1.3a
0.95
7,14
0.980
1.20
7,14
0.363
1.13
7,14
0.396
0.56
7,14
0.775
Carlo snap beans planted on 12 April. Plots 4 rows x 70 ft with 2 row untreated border, RCBD with 3
reps. Treatments applied with a CO2-powered backpack sprayer on 30 May. Column means with the
same letter are not significantly different, Waller-Duncan K-ratio t-test (P=0.05).
Table 7. Control of stink bugs (southern green, brown and green, combined) on snap beans treated
with selected foliar insecticides, Tift County, GA, 2006.
Insecticide and
Stink bugs per 25 sweeps
lbs. AI/acre
Pre-t
3 DAT
7 DAT
10 DAT
Capture 2EC
Orthene 97PE
Warrior 1CS
Lannate 2.4LV
Mustang Max 0.8EC
Tracer 4SC
Asana 0.66EC
Untreated
0.0625
0.73
0.025
0.6
0.022
0.078
0.04
F value
Degrees of freedom
P value
0.3a
0.3a
0.0a
0.0a
0.3a
0.3a
0.0a
0.7a
0.90
7,14
0.530
0.0b
0.0b
0.7ab
0.3b
0.0b
1.3a
0.0b
0.7ab
2.90
7,14
0.042
0.0a
0.0a
0.0a
0.3a
0.0a
0.3a
0.0a
0.3a
0.59
7,14
0.753
0.0b
0.0b
0.0b
0.0b
0.0b
0.0b
0.7ab
2.0a
2.64
7,14
0.058
Carlo snap beans planted on 12 April. Plots 4 rows x 70 ft with 2 row untreated border, RCBD with 3
reps. Treatments applied with a CO2-powered backpack sprayer on 30 May. Column means with the
same letter are not significantly different, Waller-Duncan K-ratio t-test (P=0.05).
135
Table 8. Control of arthropod predators (bigeyed bugs, nabids, and spiders, combined) on snap
beans treated with selected foliar insecticides, Tift County, GA, 2006.
Insecticide and
Predators per 25 sweeps
lbs. AI/acre
Pre-t
3 DAT
7 DAT
10 DAT
Capture 2EC
0.0625
Orthene 97PE
0.73
Warrior 1CS
0.025
Lannate 2.4LV
0.6
Mustang Max 0.8EC 0.022
Tracer 4SC
0.078
Asana 0.66EC
0.04
Untreated
F value
Degrees of freedom
P value
2.0a
3.3a
1.3a
2.3a
2.0a
4.0a
3.0a
3.0a
1.3c
2.3ab
0.3d
2.7a
1.3c
1.0cd
0.3d
1.7bc
0.3a
0.7a
0.7a
0.7a
1.5a
1.5a
0.3a
0.3a
2.0a
2.3a
1.0a
3.0a
2.3a
2.0a
1.7a
2.0a
0.93
7,14
0.516
6.77
7,14
0.001
0.68
7,14
0.688
0.44
7,14
0.859
Carlo snap beans planted on 12 April. Plots 4 rows x 70 ft with 2 row untreated border, RCBD with 3
reps. Treatments applied with a CO2-powered backpack sprayer on 30 May. Column means with the
same letter are not significantly different, Waller-Duncan K-ratio t-test (P=0.05).
136