Chinch Bugs can cause extensive damage to St Augustine Grass

Chinch Bugs can cause extensive damage to St Augustine grass, but has also been found in Zoysia, Bermuda and Centipede grasses. But the highest damage is typically St. Augustine grasses. The adult Chinch Bug is about  1/5 th of an inch long and black with white wings folded over their backs.  Chinch Bugs can fly so it is difficult to keep Chinch Bugs out of your yard if they are emerging from golf course, and a neighbor’s yard.

You will want to check for Chinch Bug Infestations early on sunny days, it will help make them more distinguishable.  Injury to grass resembles yellow to brownish patches in the turf.  Chinch Bugs love the sun and will not typically attack full shade areas of turf.

Professionals  trying to determine when to treat for Chinch Bugs is when they locate approximate action threshold (level at which damage begins to appear) for Chinch Bugs on susceptible St. Augustine grass varieties is 20 to 25 Chinch Bugs per square foot.

A Homeowner can perform their own sampling method by simply parting the grass and looking for the insects is the flotation method.   A coffee can (with the top and bottom lids removed) should be pushed into the ground with a twisting motion. Use a knife, if necessary, to cut the grass around the rim. Fill the can with water for about 10 minutes and check for Chinch Bugs as they float to the surface. Action thresholds for samples taken with 4-inch and 6-inch diameter coffee cans are an average of two, and four to five Chinch Bugs per sample, respectively. Several samples should be taken from different locations in the damaged (not dead) grass.

The big-eyed bug closely resembles and is often confused with the Chinch Bugs.  Big-eyed bugs are beneficial predators that kill Chinch Bugs and many other pests.  Although similar in size to Chinch Bugs, big-eyed bugs have large, protruding eyes and a head at least as wide as the thorax (the leg-bearing part of the body).  Chinch Bugs have small heads; eyes are small in proportion to the head; and their bodies are more slender. Big-eyed bugs do not have the distinctive white wings with black triangular marks that Chinch Bugs have.

One ShotThere are numerous chemicals that are labeled for Chinch Bug control in your lawn.  These include bifenthrin (Talstar®), imidacloprid (Merit®), and permethrin (Tengard) Use of surfactants in spray solutions may enhance control, especially in turf with heavy thatch.

If you seemed to be constantly plagued with a Chinch Bug Issue then Regular, light top-dressing of turf grass with compost, or soil similar to the existing soil, can help lessen thatch problems.

In turf grass that is regularly infested with Chinch Bugs, use organic, or slow-release, nitrogen sources and try lowering the rate of applied nitrogen. Lower rates of nitrogen applied to the lawn have been shown to make grass less attractive to Chinch Bugs and can reduce the need for sprays.

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.   Knowing how to determine the Chinch Bug population will help you determine the proper method of control and elimination.

Monica Bird (926 Posts)

Monica’s compassion for her customer's struggles with pest control issues and passion for pest control stems from over 10 years in the industry. With a master’s degree in entomology, she uses her knowledge and experience in chemistry, insects and pests to educate her customers.


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