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Progress Report Series No. 79 MA i' ,
Agricultural Experiment Station
AUBURN UNIVERSITY
May 1960
E. V. Smith, Director
Auburn, Alabama
Controlling Chinch Bugs on
St. Augustine Grass Lawns
W. G. EDEN, Entomologist
R. L. SELF, Plant Pathologist, Ornamental Horticulture Field Station
T HE CHINCH BUG
1 
is a serious pest of St. Augustine
grass lawns in Alabama. Infested grass may be
severely damaged or killed by this pest unless
control measures are used.
Chinch bugs damage grass by sucking the sap
from the plants. Many bugs collect at the base
of one plant, suck the sap from it, then leave to
attack adjoining plants. This causes damage to
appear in spots in a lawn. In fact, the first sign
of chinch bug injury in St. Augustine grass is
small spots of yellow grass. The spots increase
in size as the bugs increase in numbers and
attack new plants. A lawn may have several
spots that join and cover the entire area. Plants
that are attacked turn from green to yellow and
finally to brown as the grass withers and dies.
1 Blissus leucopterus insularis Barber, Family Lygaeidae.
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DESCRIPTION and LIFE HISTORY
2 
I
There are three stages in the life cycle of the
chinch bug - egg, nymph, and adult.
The adult chinch bug is black-bodied and about
1/5-inch long. It has white wings that reach
almost to the tip of the abdomen. The upper
pair of wings has a black spot on the outer mar-
gin of each wing. Legs of the chinch bug are
yellowish to red.
Chinch bugs pass the winter in the adult stage
in dead grass, leaves, and other litter. In deep
grass the bugs crawl down into the sod and
hibernate. The bugs emerge from hibernation
2 Watson, J. R., The Chinch Bug on St. Augustine Grass
Lawns, Fla. Agr. Expt. Sta. Bul. 371, 1925.
3 Wilson, R. N., The Chinch Bug in Relation to St. Augus-
tine Grass, U.S. Dept. of Agr. Cir. 51, 1929.
it,~ ~ thn\la
Ll)r
2
w
Different stages in the life cycle of the chinch bug are shown 
stages of the nymph, with the adult form at extreme right.
above. From left to right (beginning at top left) are the five The adult 
measures about 1/5 inch long. (USDA photos.)
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aim
pail
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ncn to
s;t. to t
olf winl
,;F L~C~A~G
ring
,IOitS'
aa] 1 r in
rass is ye'lP~vi"" '
~cr ease Chinch
s and in dead g i~v~al grass the
Pl;~ints hibernate.
when the weather warms up in the spring. Soon
after emergence they mate and begin to lay eggs.
Eggs are laid on the grass near the surface of
the soil or they may be scattered about in the
soil. The very small eggs are whitish at first but
gradually turn to amber or red. They hatch in
about 2 weeks into nymphs that have the same
form as adults, except for being smaller and wing-
less.
Nymphs are yellow when first hatched but
soon change to red and have a pale band across
the abdomen. They molt four to five times before
becoming adults. Just before the adult stage is
reached, the nymphs change to, a brownish-black
color and have wing pads. The nymphs require
about 30 days to, reach maturity, and adults begin
to lay eggs: in 7 to 10 days.
The total life cycle of the chinch bug is 7 to
8 weeks. Two or more generations per year occur
in the Mobile area. However, the generations
overlap to, such an extent that all forms are pres-
ent after early summer.
Chinch bugs have an offensive odor, especially
when crushed. A severely infested lawn has an
odor that can be detected by walking across it,
RESEARCH on CONTROL
This publication reports results of research on
chinch bug control conducted in Mobile in 1959.
The experiment was done on the lawn of the Ala-
bama Trade School.
Observations were begun in early spring for
presence of chinch bugs in the St. Augustine
grass. At that time only a few bugs were found.
These were hibernating in mulch around orna-
mental plants. By early June the bugs had moved
out into the grass and were increasing in number.
The experiment was begun June 18.
In the experiment, 26 different insecticides were
applied at various rates as sprays and/or granules.
A total of 40 treatments was included. Plots
were square, 1/1000-a6re areas of St. Augustine
sod. All treatments were replicated fo'ur times.
The sprays were applied to, the plots in 2 gallons
of water (equal to 0.07 inch rainfall). Granules
were spread evenly over the plots by hand, then
2 gallons o'f water was applied to each plot with
a power sprayer.
Infestation co'unts were made by using a metal
cylinder made by cutting both ends from a 5-
gallon can. The cylinder, which enclosed an area
of 0.6 square foot, was pushed into the sod and
filled with water. The bugs that floated to the
top in 5 minutes were counted.
4
RESULTS and DISCUSSION
Results of the experiment are presented in Ta-
ble 1. On the untreated grass, the chinch bug pop-
ulation reached a peak of 233 bugs per 0.6 square
foot of turf in the last half of July. The popula-
tion was somewhat lower in August and leveled
off at about 22 bugs per sample area in Septem-
TABLE 1. CHINCH BUG INFESTATIONS IN ST. AUGUSTINE GRASS
BEFORE AND AFTER VARIOUS INSECTICIDAL TREATMENTS
MOBILE, 1959
Treatment
1
Untreated check
Am. Cy. 18133., 4 lb. e.c._
Am. Cy. 1813, 4 lb. gran.'_
Am. Cy. 18133, 8 lb. e. c....
DDT, 5 lb. e. c.
DDT, 10 lb. e. c.
DDT, 20 lb. e. c.
DDT, 10 lb. gran.
Demeton, 2 lb. e. c.
Diazinon, 2 lb. e. c.
Diazinon, 5 lb. e. c.
Diazinon, 10 lb. e. c.......
Dibrom, 4 lb. e. c.
Dimethoate, 4 lb. e. c.....
Dimethoate, 4 lb. gran....
Dipterex, 5 lb. gran.
Endrin, 2 lb. e. c.
Ethion, 4 lb. e. c.
Guthion, 2 lb. e. c.
Heptachlor, 8 lb. e. c.
Heptachlor, 8 lb. gran..........
Malathion, 10 lb. e. c.
Malathion, 10 lb. gra n ....
Methyl Trithion, 4 lb. e. c.
Phorate, 4 lb. e. c.
Phorate, 4 lb. gran.
Phosdrin, 2 lb. e. c.
Phosphamidon, 2 lb. e. c ...
Sevin, 4 lb. w. p.
6
Shell SD-5539, 2 lb. e. c .......
Strobane, 10 lb. e. c.
Tedion, 
2 lb. 
e. c.
Thiodan, 8 lb. e. c.
Thuricide, 10 lb. w. p ...........
Toxaphene, 10 lb. gran.........
Trithion, 4 lb. e. c.
VC-13 (75%), 5 gal. e. c.....
Zytron, 10 lb. e. c.................
Zytron, 10 lb. gran.
Zytron, 20 lb. gran.
Bugs/0.6 sq. ft., by dates', av.
6/183 7/21 8/19 9/22 10/15
No. No. No. No. No.
17 233 92 22 24
14 20 38 28 19
12 8 46 21 20
6 11 24 11 14
8 6 19 8 3
12 1 8 1 1
10 2 13 2 3
11 1 5 1 1
5 36 25 7 5
49 40 87 12 18
12 6 57 12 19
16 2 81 32 18
17 147 34 9 13
8 84 34 14 19
5 61 15 8 8
11 92 49 25 20
12 9 87 5 10
16 123 64 28 14
16 85 33 23 19
11 213 54 11 19
13 67 60 20 10
11 65 25 13 15
8 39 39 36 18
9 8 23 12 14
14 3 37 22 21
11 56 35 8 44
9 112 35 7 8
8 34 33 16 13
4 71 40 9 9
14 105 52 11 24
6 63 25 9 6
7 73 33 8 12
8 75 38 7 27
8 123 47 15 13
4 10 22 9 18
34 10 13 3 8
4 4 31 7 10
18 2 28 8 9
11 3 15 2 4
SRates are pounds of technical material per acre.
2 Mean of two samples per plot and four 
replications.
' Counts were made prior to treatment on June 18.
SEmulsifiable concentrate.
' Granules.
' wettable powder.
4 Kerr, S. H., Personal correspondence to W. 
G. Eden dated
May 8, 1959.
ber and October. Some of the insecticidal treat-
ments were effective throughout the summer, some
for shorter periods, and some were ineffective.
DDT at 5, 10, or 20, pounds per acre as sprays
or 10 pounds: per acre as granules, and Zytron at
20 pounds: per acre as granules protected the grass
for the longest period (4 months). Ten pounds
of DDT per acre as spray or granules appeared
to, be slightly more effective than 5 pounds as a
spray; however, 20 pounds as a spray was no bet-
ter than 10 as spray or granules.
Zytron at 20 pounds per acre as granules was
effective for the 4-month period of the experiment,
but 10 pounds as granules or spray was somewhat
less efficient. VC-13 at 5 gallons per acre con-
trolled the bugs for 3 months but appeared to lose
some of its effectiveness thereafter.
Ethion and Dipterex appeared to have some
residual action against the chinch bug after 1
month, but their performances were not as good
as DDT, Zytron, or VC-13. Diazinon at 5 or 10
pounds per acre as a spray was highly effective
for 1 month but had little residual effect there-
after. American Cyanamid 18133 at 4 pounds per
acre as granules or 8 pounds per acre as a spray
controlled the chinch bug for 1 month but was
less effective after 1 month. Four pounds per
acre of the compound as a spray did not control
the insect.
Zytron at 10 pounds per acre or phorate at 4
pounds as spray or granules was effective for 1
month but then lost some effectiveness. Trithion
at 4 pounds per acre as a spray controlled the
chinch bug for 1 month after application. The
most effective treatments and lengths of their
effectiveness are summarized in Table 2.
There have been reports that the chinch bug
was resistant to DDT in Alabama, but there was
no indication of resistance in this experiment.
One application of DDT at the 10-pound rate as
spray or granules gave excellent control of the
insect throughout the summer. If resistance to
DDT develops, good control of the insect may be
had with other insecticides.
Phorate and American Cyanamid 18133 are
extremely toxic compounds and should not be
used by the average person. Ethion and Trithion,
though less toxic than the above two, are highly
toxic. Diazinon and VC-13 are considerably safer
than any of the previously mentioned insecticides,
but they must be used with proper precaution to
prevent ingestion, inhalation, or skin absorption.
DDT and Zytron are relatively safe to handle, but
TABLE 2. LENGTH OF EFFECTIVENESS OF INSECTICIDAL
TREATMENTS AGAINST THE CHINCH BUG ON ST.
AUGUSTINE GRASS, MOBILE, 1959
Treatment L
DDT, 5 lb. e. c.
DDT, 10 lb. e. c.
DDT, 20 lb. e. c.
DDT, 10 lb. gran.
Ethion, 4 lb. e. c.
Dipterex, 5 lb. gran.
Diazinon, 5 lb. e. c.
Diazinon, 10 lb. e. c.
Am. Cy. 18133, 4 lb. gran.
Am. Cy. 18133, 8 lb. e. c.
Zytron, 10 lb. e. c.
Zytron, 10 l1b. gran.
Phorate, 4 lb. e. c.
Phorate, 4 lb. gran.
Trithion, 4 lb. e. c.
Chinch bugs/0.6 sq ft. in untreated plots
I month
2 m o n th s .. . . . . . . . . . . . . . . . . . . . . . . .
3 months
4 months
ength of effectiveness
2
Months
43
4
4
4
4
3
2
5
1
1
Av. no.
233
92
22
24
1 Rates are pounds of technical material per acre.
2 Effective control was measured as less than 15 bugs per
0.6 square foot at 1 and 2 months and less than 5 bugs at 3 and
4 months. Counts were discontinued after 4 months.
SNot effective at 2 months, but within effective range at
1, 3, and 4 months.
Within the effective range at 1 and 3 months but not at
2 months.
Within the effective range at 2 months but not at 1 month.
normal precaution in handling poisonous com-
pounds should be used with them.
SUMMARY
Unless control measures are used, St. Augus-
tine grass infested with chinch bugs may be se-
verely damaged or killed.
The chinch bug overwinters as an adult and
begins to feed as soon as the weather becomes
warm in the spring.
The first sign of chinch bug injury in lawns is
small spots of yellowing grass; the spots increase
in size as the summer progresses.
Populations of chinch 
bugs reached the 
highest
peak in 1959 in late July.
Excellent control of the chinch bug was obtained
throughout the summer in 1959 with one applica-
tion of 10 pounds of DDT per acre as spray or
granules. Twenty pounds of Zytron as granules
also controlled the insect throughout the summer.
VC-13 at 5 gallons per acre as a spray was ef-
fective against the chinch bug for 3 months. Diazi-
non, Trithion, and some other phosphate insecti-
cides controlled the insect for 1 month.