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LEAFLET 97, SEPTEMBER 1978
Evaluation of Insecticides For Control
Of Bean Leaf Beetles
PAUL S-B. CHILI and MAXH. BASS*
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MATE RIALS AND METHODS
AGRICULTURAL EXPERIMENT STATION
EtenntABUR UNIVERSITY Al~tr AabmR Dennis Rouse Director
Auburn, Alabama
1976, at the Auburn University Agricul-
tural Experiment Station's Black Belt
Substation, near Marion Junction, Ala-
bama, to determine effective rates of in-
secticides for control of bean leaf beetles
on soybeans. Insecticides selected on
the basis of present or potential use
were: methomyl,' methyl parathion,
acephate, toxaphene-methyl parathion,
methamidophos, Mobil 9087, chlor-
pyrifos, fonofos, Bolstar?, Sevimol?
(carbaryl and molasses), carbaryl,
DS24-465, permethrin (Ambush?), per-
methrin (Pounce*), Pydrin
?
, curacron
?
,
GCP 9646, encapsulated methyl para-
thion (Penncap-M?), Bay 92114, dimeth-
oate, carbofuran, diazinon, and lepto-
phos.
Plots of Bragg soybeans were four rows
wide (40 in. rows) and 37 feet long in all
tests. Tests were arranged in a ran-
domized complete block replicated four
times. Sprays were applied (one applica-
tion only) using a CO
2 
pressurized
sprayer calibrated to deliver 12.5 gallons
of insecticidal spray per acre.
Counts of live bean leaf beetles were
made 24 hours after treatment. Beetles
were collected from the two middle rows
of each plot using a sweepnet. Each
count represented 25 sweeps, and each
sweep consisted of sweeping across and
through two rows of soybeans. Percent
control was calculated according to this
formula:
No. in check - no. in 
treatment x 100
no. in check
The bean leaf beetle has been con-
trolled with several insecticides at rates
as low as 1 lb/acre (4,7). Thus, the highest
rate used for any insecticide evaluated in
these tests was 1 lb/acre. Subsequent
tests utilized progressively lower rates
until effectiveness was lost. A few mate-
rials (synthetic pyrethroids) were tested
at rates as low as 0.025 lb/acre.
The economic injury threshold, based
on number of beetles per foot of row, has
not been established for the bean leaf
beetle. However, for purposes of deter-
mining adequate effectiveness of mate-
rials for use in making control recom-
mendations, many researchers have used
80 percent control as an acceptable level.
This criterion for evaluation was utilized
in these tests.
RESULTS
In the series of tests conducted in
1975, Bolstar? and acephate provided
acceptable control at 1 lb (active ingre-
dient)/acre, but not at lower rates, table 1.
Methomyl, methyl parathion, toxa-
phene-methyl parathion, methamido-
phos, chlorpyrifos, carbaryl, and DS24-
465 provided acceptable control at rates
as low as one-half lb ai/acre. Sevimol?,
Mobil 9087 and fonofos did not provide
80 percent control at any rate tested.
Two series of experiments were con-
ducted in 1976. Data from the first series
of experiments are presented in table 2.
In the series of tests presented in this
table, the minimum rate which afforded
at least 80 percent control of the bean leaf
beetle was 1 lb/acre for Curacron?, 0.75
lb/acre for GCP 9646, and one-half
lb/acre for Penncap-M?, dimethoate,
diazinon, and leptophos.
In the second series of tests conducted
in 1976, table 3, the minimum rate tested
which provided at least 80 percent con-
trol was 0.5 lb/acre for Bay 92114 and
carbofuran, 0.125 lb/acre for Pounce?,
0.1 lb/acre for Ambush?, and 0.05 lb/acre
for Pydrin?.
The following is a combined list of all
materials tested which provided 80 per-
cent or better control at some tested rate.
The list is in order based on the
minimum effective rate per acre (80 per-
cent control) and starting with the mate-
rial effective at the lowest rate: 0.05 lb.,
Pydrin?; 0.1 lb., permnethrin (Ambus
h
?);
0.125 lb., permethrin (Pounce?); 0.5 lb.,
Bay 92114, carbofuran, leptophos, diazi-
non, dimethoate, encapsulated methyl
parathion (Penncap-M?), DS24-465, car-
baryl, chlorpyrifos, methamidophos,
toxaphene-methyl parathion, methyl pa-
ration, and methomyl; 0.75 lb., GCP
9646; 1 lb., Curacron?, and Bolstar?.
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TABLE 1. PERCENT CONTROL AND AVERAGE NUMBER OF LIVE ADULT BEAN LEAF BEETLES PER 25 SWEEPS PER PLOT 24 HouRS
AFTER TREATMENT WITH INDICATED RATES OF INSECTICIDES. 1975
1 lb AI/A (Test 1) 0.5 lb AI/A (Test 2) 0.25 lb AI/A (Test 3) 0.125 lb AI/A (Test 4)
Live Live Live Live
Insecticide beetles' Control beetles' Control beetles' Control beetles' Control
No. Pct. No. Pct. No. Pct. No. Pct.
Carbaryl 80S ........... 0.2 96 0.5 95 5.2 5 4.5 36
Methomyl 1.8L ........ 0.5 92 0.8 86 4.0 27 6.2 11
Methyl Parathion 4EC .. 0.5 92 0.2 95 4.0 27 5.2 25
Acephate 75S .......... 1.0 84 1.2 76 4.0 27 5.2 25
Toxaphene-Methyl
Parathion 6-3EC
2 
..... 1.0 84 1.0 81 4.0 27 5.0 29
Chlorpyrifos 4EC ...... 1.2 80 1.0 81 4.5 18 3.8 46
Methamidophos 4EC ... 1.2 80 1.0 81 2.5 55 4.8 32
DS 24-465 3.6EC ....... 1.2 80 0.2 95 3.0 45 4.5 36
Bolstar? 6EC .......... 1.2 80 1.8 66 2.0 63 4.0 43
Fonophos 4EC ......... . 1.8 72 1.2 76 4.7 14 3.5 50
Mobil 9087 2EC ....... 2.0 68 1.5 71 4.0 27 5.0 29
Sevimol? 4 ............ 2.2 64 1.5 71 4.0 27 6.0 14
Check - ............... 6.2 - 5.2 - 5.5 - 7.0 -
'Mean of four replications.
2This mixture was applied at the designated rate for toxaphene and 1/2 that rate for methyl parathion.
C)
TABLE 2. PERCENT CONTROL AND AVERAGEENUMBER OF LIVE ADULI BEAN LEAF BEETLES PER 25 SWEEPS PER PLOT 24 HOURS
AFTER TREATMENT WITH INDICATED RATES OF INSECTICIDES. 1976
Insecticide
Penncap-M? 2EC.
Diazinon 2EC .........
Dimethoate 2.67EC ..
Leptophos 2.7EC ...
Curacron? .............
GCP 9646 6EC ........
Check ........
1 lb Al/A (Test 1)
Live
beetles' Control
No. Pct.
0.0 100
0.2 97
1.,0 89
1.0 89
1.0 89
1.8 81
9.0-
0.75 lb AI/A (Test 2)
Live
beetles' Control
No. Pct.
0.5 95
1.0 89
1.8 82
1.2 87
2.5 74
1.8 82
9.5-
0.5 lb Al/A (Test 3)
Live
beetles' Control
No. Pct.
0.2 96
1.2 81
0.0 100
1.0 85
2.2 65
2.2 65
6.5
0.25 lb Al/A (Test 4)
Live
beetles'
No.
3.8
6.8
6.2
9.2
4.8
8.0
9.2
Control
Pct.
59
27
33
0
-49
14
'Mean of four replications.
TABLE 3. PERCENT CONTROL AND AVERAGE NUMBER OF LIVE ADULT BEAN LEAF BEETLES PER 25 SWEEPS PER PLOT AT
INDICATED INSECTICIDAL RATES. 1976
Ambush? 2EC Pydrin 2.4EC Pounce? 3.2EC Bay 92114 6EC Carbofuran 4EC Check
Live Live Live Live Live Live
Rate Al/A beetles' Control beetles' Control beetles' Control beetles' Control beetles' Control beetles'
No. Pct. No. Pct. No. Pct. No. Pct. No. Pct. No.
1.000 lb 0.0 100 0.2 97 0.0 100 9.0
0.750 lb 0.5 95 0.5 95 0.2 97 9.5
0.500 lb 0.2 96 0.8 88 0.0 100 6.5
0.250 lb 0.5 94 2.8 70 3.8 59 9.2
0.200 lb 0.0 100 0.2 97 9.0
0.125 lb 1.0 90 7.5 25 5.8 43 10.0
0.100 lb 0.2 97 1.2 87 9.5
0.050 lb 1.8 73 1.2 81 6.5
0.025 lb 5.0 46 5.2 43 9.2
'Mean of four replications.
------- .. 1. . %
rS
, /,
SqA
1 16 i
t
a,
4%
Bean leaf beetles have several different color phases due to genetic 
variation, as shown
in the above photographs.
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LITERATURE CITED
(1) Ditman, L. P., and E. N. Cory. 1948. Liquefied 
gas aerosols to control
bean beetles. J. Econ. Enotomol. 41(2): 268-275.
(2) Duncan, D. V. 1955. Multiple range and 
multiple F tests. Biometrics.
11(1): 268-275.
(3) Dupree, M. 1970. Control of thrips and bean leaf 
beetle on lima beans
with systemic insecticides. Ga. Entomol. Soc. J. 
51(1): 48-52
(4) Evans, W. 1968. Fighting with pests that eat 
soybean profits. Farm.
Quart. 23(2): 102-105, 117-120.
(5) Miner, F. D. 1966. Soybean insect problems in Arkansas. 
Proc. N. Cent.
Br. Entomol. Soc. Amer. 21-54.
(6) Petty, H. B. 1967. How to control soybean insects. 
Farm Tech. 23(1):
42a-47a.
(7) Waldbauer, G. P., and M. Kogan. 1976. Bean leaf beetles: 
Bionomics
and economic role in soybean agroecosystems. World 
Soybean Re-
search. 619-628.
Information contained herein is available to all, regardless of race,
color, or national origin.
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