
Chinch
Bugs, Their Damage and Elimination
Chinch bugs are most damaging to St. Augustine grass. You may see them
on grasses such as zoysia, Bermuda, and centipede, but infestations
usually occur where high populations have built up on St. Augustine
grass. Adult chinch bugs are about one-fifth of an inch long and black
with white wings folded over their backs. The insect mates early in the
season when the temperature reaches 70 degrees Fahrenheit. The female
lays eggs on roots, stems, leaves, leaf sheaths or crevices in nodes
and other protected places. Eggs are laid over a 2 to 3 week period,
with one female laying as many as 500 eggs.
The
young chinch bugs ( called nymphs) develop into adults in four to six
weeks. Nymphs are yellow upon hatching but soon turn red and have a
light colored band across their abdomens. With each molt, nymphs more
closely resemble the adults. There are 2 to 4 generations per year.
The
chinch bugs insert their slender beak into the grass and suck the plant
juices. As the chinch bug sucks the plant juices, it releases a toxin
that causes yellowish to brownish patches in turf. Typical injury
appears as spreading patches of brown, dead grass. This pest is a
sunshine-loving insect and seldom attacks grass in a dense shady area.
Discolored areas caused by chinch bug feeding that are in open sunlight
several hours daily may be "hot spots" for chinch bug damage. Most
homeowners will first notice dead patches of grass along a driveway,
curb, sidewalk or foundation of the home, due to the heat emitted from
such objects.
Because they can fly, it is difficult to keep an
area free of chinch bugs if they are emerging from neighboring lawns,
golf courses or nearby croplands.
Inspecting For Chinch Bugs
Scout turf on sunny days by slowly sliding your foot through the sod
and watching for the bugs to crawl across your shoe. You can also
determine infestations by using a large coffee can or gallon can with
both ends removed. Press one end of the can about 2 or 3 inches into
the soil, fill with soapy water, and watch for about 5 minutes. If
chinch bugs are present, they will float to the surface. (This test
will also bring molecrickets to the surface) It is very important to
check areas where the yellowish spots and the green grass meet in
several different locations.
Controlling
Chinch Bugs
Chinch bugs have become resistant to almost every pesticide used to
control them. They were even resistant to DDT in the early 1950s. Of
the many insecticides labeled for chinch bug elimination, there are two
that stand out above the rest: Talstar (which contains Bifenthrin) and
Acephate. For the past several years, Acephate had been the best
overall performer in eliminating chinch bugs in lawns, giving better
control than other products being used by professionals and homeowners
alike. However, Talstar has suddenly become the star performer in
eliminating lawn and turf pests such as molecrickets, ants and chinch
bugs.
For
best results, wet turf thoroughly with water before applying an
insecticide. Treat the entire area evenly and thoroughly. Wet the area
with water again after applying the insecticide. Where chinch bug
infestations are heavy, re-treat the area in 2 weeks to kill recently
hatched insects, unless you are treating with Talstar. In this case,
repeat applications may not be necessary.
Talstar liquid
concentrate should be applied through a hose end sprayer at the rate of
1/2 ounce per 1000 square feet. Talstar granules should be applied at
the rate of 25 pounds per 1/4 acre and irrigated immediately after
application.
Acephate should be applied through a hose end sprayer at the rate of 1 pound per 1/4 acre in sufficient water.
The hatch
removal is important for eliminating conditions favorable for chinch
bug survival. Maintaining adequate moisture will increase the tolerance
of turf to feeding damage and will promote beneficial fungi that attack
chinch bugs. Low nitrogen fertilization slows chinch bug reproduction
although the lawns regularly attacked by these insects (St. Augustine)
are heavy feeders and prefer more fertilizer than other turf grasses.
Consult your local county extension office about feeding your St.
Augustine grass.