Chinch bugs have
piercing-sucking mouthparts and they feed on the sap of grass plants.
They reside in the thatch area of the turfgrass stand and prefer
to feed on the lower leaf sheath and crown area of the plant. The
chinch bug can be a major insect pest on home lawns throughout the
country. The adult chinch bugs are about 1/8 to 1/5 inches in length and
black with white markings on the wings. The wings rest flat over the
back of the insect and there is a black spot between the wings. Adults
may be long-winged or short-winged. There are five nymphal instars of
chinch bus ranging in size from 1/32 to 1/5 inches. The first two
nymphal instars are red, with a white band across their abdomen, while
the third and fourth instars are orange with wing pads just beginning to
appear. The fifth instar is black with wing pads easily visible.
The chinch bug inserts its straw-like mouthparts into the plant tissue
and sucks out the plant juices while injecting chemicals into the plant
which clog the vascular system. The area around the feeding puncture
usually turns yellow. Damaged areas first appear as small, irregular
patches which enlarge as the insects spread. Chinch bugs are most
damaging in open, sunny areas.
Chinch bugs spend the winter months as adults in partially protected
areas (under shrubs or around foundations of houses). As the weather
warms in the spring, adults move into open areas, where females begin
laying eggs. 15 to 20 eggs per day are deposited for two to three weeks.
The eggs hatch in one to two weeks, and the nymphs begin to suck the
juices from host plants. It takes 30-90 days to reach adulthood. There
are two generations per year, with a partial third generation in
unusually warm summers. There is considerable overlap of generations,
and all stages can be found during the summer.
You must really examine the grass in the marginal areas of injured
patches, not in the clearly dead grass. Spread the grass gently with
your fingers and look in the thatch, near the soil surface. Chinch bugs
are usually very active in the summer, so you will be able to see them
scurrying around, especially on warm summer days. An alternative method
of detecting chinch bugs is to remove both ends of a large tin can, such
as a coffee can. Soften the soil a little with water, and insert one end
of the can into the ground at least 2-3 inches deep, leaving at least 4
inches of the can above the ground. Fill the can with water and wait
about five minutes. If chinch bugs are present, they will float to the
surface of the water, where you can count them.
In many instances, chemical control of chinch bugs is not necessary.
Many lawns have natural populations of predators, such as ground beetles
or "big-eyed bugs," which can keep chinch bug populations from getting
out of hand. Insecticide applications sometimes have very adverse
effects on these predators, causing the chinch bug populations to
develop more rapidly in subsequent years. Plant resistance has also been
reported for a number of turfgrass species and cultivars.
To avoid this problem in areas with habitual problems, an April to mid
May insecticide application will control the overwintering females and
subsequent generations during the summer. Reinfestation may occur from
adjacent areas, but this process is slow and may require an additional
year or more. This adult treatment must be made before egg laying
occurs. As with any pesticide application, be sure to read the label and
apply the material at the specified rate. Avoid mowing the area for two
or three days afterward.
Contact us to determine if these bugs are causing you a problem, and
discuss which insecticides would be most effective for controlling these