Answers to your chinch bug queries

Published 1:31 am Sunday, July 1, 2007

I have been receiving several calls about chinch bug problems with St. Augustine lawns. To most homeowners with St. Augustine lawns this should be a concern, however it is important to first be able to properly detect and identify this lawn. These following questions should help answer several questions on the aggravating pest.

Q. How do I know if I have chinch bugs?

Chinch bugs are major pests of St. Augustine lawns, but they are rarely a problem in other types of grasses. Chinch bugs especially favor the more sunny areas of the lawn, and damage will likely occur in these areas first. Therefore you will first start seeing problems in open areas of your lawn that receive full sun. Chinch bugs tend to be of greater concern during prolonged dry periods. Adult chinch bugs are approximately 1/5 of an inch or less in length and are black with white wings that are folded in an ‘X’ over their back. The nymphs, or immature chinch bugs, are red with a light-colored band across the back.

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Q. Where do I look for chinch bugs at?

In order to properly identify these pests it usually requires you to get down on your knees and part the grass between where it is injured and healthy. It is best to scout turf on sunny days by parting the stems and looking for the small, reddish nymphs and/or the black and white adults in the crown region or running across the exposed soil. Another method is to remove both ends of a gallon-sized can, press one end of the can two to three inches into the turf, and then fill the can approximately half full with water. If chinch bugs are present, they will float to the top within a few minutes. When using this method it is important to check several sites, choosing areas where the yellow and green grass meets.

Q. What causes chinch bugs to kill the lawn?

While feeding, they inject a toxin, and it is this toxin that causes heavily infested areas to turn yellow, then brown and eventually die. Because, there are several diseases and other problems that can cause similar damaged areas in St. Augustine lawns, it is important to verify the presence of chinch bugs before initiating treatment.

Q. How do I treat chinch bugs?

If chinch bugs are identified as the cause of the problem, they can be controlled with common insecticides. If the infestation is heavy, a second application should be applied approximately two weeks after the initial treatment. For control of chinch bugs, liquid treatments are usually more effective than granular treatments. Many of the liquid insecticides are available in ready-to-use hose-end applicators, which is a convenient way for homeowners to apply chinch bug treatments. Some insecticides that are effective include Sevin Concentrate Bug Killer, Triazicide Soil & Turf Insect Killer Concentrate or Hi-Yield 38 Plus Turf, Termite & Ornamental Insect Concentrate. Some of these products recommend you water your lawn before or after treatment so be sure to read the label.

For more information I encourage you to visit the Mississippi Extension Service Web site at If you have any further questions concerning lawn pest or other agricultural problems please contact me at the Adams County Extension Office at 601-445-8201 or by e-mail at

David Carter is director of the Adams County Extension Office.