University of Florida IFAS
Ft. Lauderdale ARC Research Report FL 78 1
January 16, 1978
RESISTANCE TO ORGANOPHOSPHATE AND CHLORINATED CYCLODIENE
INSECTICIDES BY THE SOUTHERN CHINCH BUG 1976 AND 19771/
James A. Reinert2 HUiI LiRARY
Harry D. Niemczyk3/ A 14
I.F.A.S. Univ. of Floida
Experiments with diazinon, chlorpyrifbr and other organophosphate insecti-
cides gave poor control of the southern chinch bug, Blissus insularis Barber
on home lawns in southern Florida in 1976 and 1977. Spray. tower lab tests
confirmed that chinch bugs from these lawns were resistant to diazihon,
chlorpyrifos as well as chlordane and dieldrin. A high degree of suscepti-
bility was shown to propoxur and two synthetic pyrethroids; PP-557 or
FMC-33297 ((3-phenoxyphenyl) methyl () cis-trans-3(2,2-dichloroethenyl)-2,
dimethyl cyclopropanecarboxylate) and SC-43775 (Benzeneacetic acid 4-chloro-
alpha- (l-methylethyl) -cyano (3-phenoxy-phenyl) methyl, ester).
The southern chinch bug is the most serious pest of St. Augustinegrass
Stenotaphrum secundatum Walt. Kuntz which is widely used for turfgrass in
Florida and throughout the southern coastal states and California. According
to McGregor (1976), turfgrass maintained in Florida in 1974 totalled more than
368,700 ha (911,000 acres) of which St. Augustinegrass comprised 37% of the
1/ This information in part has been submitted to the Journal of Economic Ento-
mology for publication.
2/ Associate Professor of Entomology, Univ. of Fla., IFAS, Agr. Res. Center,
Ft. Lauderdale, Fla. 33314
3/ Professor of Entomology, Ohio Agr. Res. and Dev. Center, Wooster, Ohio 44691
First evidence of insecticide resistance in the southern chinch bug was
noted in Florida in 1957 when DDT failed to give good control (Kerr 1958, Kerr
and Robinson 1958). In 1961, reduced effectiveness with parathion was reported
(Kerr 1961). Resistance in 2 other.Blissus spp. including B. pulchellus to
cyclodienes and B. leucopterus to organophosphates has also been reported
(Georgiou and Taylor 1977).
Beginning late in the summer of 1975, lawn spray operators began to observe
reduced effectiveness with various organophosphate insecticides. By 1976
several spray companies and garden centers in southern Florida (Broward and
Palm Beach Counties) reported no control of the southern chinch bug with either
chlorpyrifor or diazinon. The following report documents resistance to both
chlorinated cyclodienes and organQphosphates and efforts to develop substitute
METHODS AND MATERIALS
Field Tests.--Residential lawns of St. Augustinegrass in the southern
Florida communities of Delray Beach and Pompano Beach, each with a heavy in-
festation of chinch bugs and a history of damage despite applications of
organophosphate insecticides were used to evaluate various insecticides.
Fifteen insecticides were applied to 4 replicates of randomized plots of 9.3 m2
in 1976 and 4.6 m2 in 1977 experiments. A sprinkler can was used to apply the
water-insecticide mixture at a rate of 0.8 liters/m2. Treatments were washed in
with an additional 1.6 liters/m2. A final experiment evaluating PP-557 was
conducted in 1977 using 3 home yards each with ca 55-75 m2 of infested turf.
In each yard, the infested area, was divided in half and only half of this in-
fested area was treated by a commercial lawn spray company.
Chinch bug populations were measured prior to applications and at either
7 or 7 and 14 days posttreatment. Samples were made by forcing a metal cylinder
34.7 cm in diam (=0.09 m2) into the turf, filling it with water, and counting
the chinch bugs that surfaced in 8 minutes. Populations of 100 or greater were
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recorded as 100.
Lab Tests.--Adult southern chinch bugs for lab testing were collected in
1976 from the lawns used in field experiments 1 and 2 and from turf in Fort
Lauderdale where the population was known to be susceptible to organophosphate
insecticides. Chinch bugs were floated to the surface by the aforementioned
process, picked off and placed in inflated plastic bags containing stolons
of St. Augustinegrass which served as food. The bags were placed in styro-
foam boxes, surrounded with styrofoam packing insulation and shipped air
express to the Ohio Agricultural Research and Development Center, Wooster, Ohio.
Upon arrival, the bags were removed and placed in a holding room maintained at
24 10C and 60- 5% RH for 24 h prior to testing. Mortality in transit was
Stock solutions (1%) of test insecticides were prepared from analytical or
technical grade materials using a mixture of acetone and olive oil, 19:1 (vol/vol)
as the solvent. For each experiment 2 replicates of 10 bugs anesthetized with
ether were placed on filter paper in 9 cm glass petri dishes. Each replicate
was sprayed with 5 ml of each insecticide in concentrations of 0.001%, 0.01%,
0.1%, and 1.0%. The checks consisted of 2 sets of 2 replicates of 10 bugs from
each location sprayed only with the solvent.
The solutions were applied with a Potter Spray Tower, modified as described
by Harris and Mazurek (2). Twelve sec were allowed for delivery and 18 sec for
settling. Each group of 10 chinch bugs was removed from the petri dish and placed
in a paper cup provided with 5% honey on rolled dental cotton stapled to the in-
side. The cup was covered with a glass petri dish and placed in the room in
which the insects were conditioned prior to treatment. Corrections for check
mortality (average 5%) were made using Abbott's formula.
RESULTS AND DISCUSSION
Field Tests.--Population evaluations in 1976 at Delray Beach 7 days after
treatment showed fonofos was the only organophosphate giving significant control
(Table 1). Even a 2X rate of chlorpyrifos failed to provide better control
than the recommended rate. Chlordane gave no control. Of the 2 carbomates
tested, propoxur gave significant and bendiocarb non-significant control.
Control with the synthetic pyrethroids, SD 43775 and FMC 33297 was significant,
but it appeared that a higher rate was needed to achieve a greater level of
control obtained with propoxur.
Since the synthetic pyrethroids appeared very promising in 1976 ex-
periments, they were evaluated again in 1977. In experiments 1 and 2 (Table 2)
all 3 synthetic pyrethroids gave significant control. In almost all instances,
when the rate was increased the level of control was also increased. In ex-
periment 2, the addition of Aqua Grow(R), a wetting agent did not appear
to increase the activity of PP-557.
In several of the treatments, 3 of the replicates yielded a very high
degree of control while the remaining replicate had a substantial number of
chinch bugs present when populations were reevaluated. Also, as the chinch
bugs were counted, it was observed that a high percentage of those present
were either 5th instars or adults. Based on these 2 observations, it was
concluded that much of the chinch bug population present in the synthetic
pyrethroid treated plots was the result of migration from untreated plots
which were adjacent to them. It was also concluded that much of the im-
migration could be eliminated by using much larger treated areas.
An additional experiment was therefore established with PP-557 at 0.84 Kg
a.i./ha using entire yards with severe chinch bug infestations. Each yard was
divided so that only one half of the infestation was treated. Experiment 3
(Table 2) shows that a very high degree of control was obtained by this treat-
ment. This test also supports the theory that by using small plots in ex-
periments 1 and 2, a moderate number of the migratory stages were able to
reinfest several of the treated plots.
Other carbamates were also evaluated for control of the southern chinch
Table 2. Results of field tests with synthetic pyrethroid insecticides for control
of southern chinch bug on home lawns of St. Augustinegrass in Pompano
Beach, Florida 1977.
AI Mcana survivorship chinch bugs/0.09m2
Insecticide kg/ha _at days posttreatmentb
0 7 14
FMC-33297 3.2EC 0.84. 99.3 33.0a 8.Sa
SD-43775 2.4EC 0.56 87..5 23.0a 31.8bc
SD-43775 2.4EC 0.84 83.0 29.3a 13.8a
PP-557 2EC 0.56 99.5 59.Ob 17.0ab
PP-557 2EC 0.84 91.0 28.8a 13.0a
PP-557 2EC 1.12 91.3 14.5a 7.5a
Chlorpyrifos 2EC 1.12 91.0 84.0c 52.5c
Untreated Check 0 99.3 79.Sc 45.8c
SD-43775 2.4EC 1.12 88.0 16.3a 8.0a
PP-557 2EC 0.84 88.0 46.3c 35.Oc
PP-557 2EC 1.12 96.3 47.5c 44.3d
PP-557 2EC 1.4 89.8 30.0b 23.8b
PP-557 2EC 1.6 90.8 13.5a 21.8b
PP-557 2EC+ 0.84+ 96.3 31.3b 33.3c
Aqua Grow 9' 8
Chlorpyrifos 2EC 1.12 90.8 54.5c 48.5d
Untreated Check 0 89.8 85.3d 58.3e
Experiment 3 e
PP-557 2EC 0.84 98.0 7.5a 3.4a
Untreated Check 0 96.0 87.2b 81.5b
aMeans in a column not followed by the same letter are
(P<0.05) by Duncan's multiple range tests.
Table 2. (cont.)
b Populations of 100 or more chinch bugs/0.09m2 were recorded as 100.
c Treated on September 16, 1977 (4 replicates).
d Treated on.September 26, 1977 (4 replicates).
e Treated on October 25, 1977 (3 replicates with 5 subsamples each).
Table 3. Results of field tests with carbamate insecticides for control of southern
chinch bug on home lawns of St. Augustinegr.ass in Pompano Beach, Florida-
AI Mean- survivorship chinch bugs/0.09m2
Insecticide kg/ha at days posttrbatment e
0 7 14
Propoxur 1.5EC 7.84 65.8 4.3a 3.0a
Bendiocarb 75WP 8.96 69.3 9.8a 5.8a
Bendiocarb 75WP 4.48 70.0 34.3b 46.8c
Carbaryl 80WP 11.2 72.5 35.5b 28.5b
Carbaryl 80WP 5.6 73.0 63.8c 67.8c
Oxamyl 2EC 4.48 71.5 52.3bc 52.8c
Pirimicarb 50WP 4.48 64.8 71.8c 64.0c
Chlorpyrifos 2EC 1.12 70.0 41.0b 49.Oc
Untreated Check 0 62.0 46.Ob 50.Oc
a Treated on September 22, 1977.
b Means in a column not followed by the same letter are significantly different
(P(0.05) by Duncan's multiple range test..
SPopulations of 100 or more chinch bugs/0.09m2 were recorded as 100.
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Table 4. Toxicity of insecticides to adult southern chinch bug from 2 locations
in southern Florida 1976.
24 hr avg. corrected % mortality at indicated % insecticide
concentration and location
Insecticide 0.001 0.01 0.1 1.0
DB FL DB FL DB FL DB FL
Chlordane 0 0 0 0- 0 31 0 37
Dieldrin 5 0 5. 26 0 42 0 84
Diazinon 0 0 0 11 0 100 5 100
Chlorpyrifos 0 0 0 32. 0 100 63 100
Trichlorfon 0 0 0 47 100 100 100 100
Carbaryl 0 0 58 100 100 100 100 100
Propoxur 68 32 100 100 100 100 100 100
PB FL PB FL PB FL PB FL
FMC-33297 5 10- 100 100 100 100 100 100
SD-43775 0 0 100 72 100 100 100 100
Propoxur 26 72 100 100 100 100 100 100
a Mortality figures corrected for check mortality with Abbott's
on 2 replicates 10 adults each from each location.
bDB = Delray Beach; PB = Pompano Beach; FL = Ft. Lauderdale
formula and based
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Georghiou, G. P. and C. E. Taylor. 1977. Pesticide resistance as an evolutionary
phenomenon. XV Inter. Cong. Entomol., Proc. Washington, D. C. Aug. 1976
Harris, C. R. and J. H. Mazurek. 1964. Comparison of the toxicity to insects of
certain insecticides applied by contact and in the soil. J. Econ. Entomol.
Kerr, S. H. 1958. Tests on chinch bugs and the current status of control. Fla.
St. Hort. Soc. 71:400-3.
Kerr, S. H. and F. A. Robinson. 1958. Chinch bug control tests, 1956-57. Fla.
Kerr, S. H. 1961. Turf research report 1961: Lawn chinch bug research.
Turf-Grass Manag. Conf.,Proc. 9:211-21.
McGregor, R. A. 1976. Florida turfgrass survey, 1974. Fla. Crop and Livestock
Rep. Serv., Orlando, Fla. 33pp.
Reinert, J. A. 1972. Control of the southern chinch bug, Blissus insularis in
South Florida. Fla. Entomol. 55:231-5.
Reinert, J. A. 1974a. Tropical sod webworm and southern chinch bug control in
Florida. Fla. Entomol. 57:275-9.
Reinert, J. A. 1974b. Turfgrass insects research 1974. Fla. Turf-Grass Manag.
Conf., Proc. 22:118-20.
Reinert J. A. 1975. Southern chinch bug and tropical sod webworm control studies.
FIs. Turf-Grass Manag. Conf., Proc. 23:93-100.