Help with my Southern chinch bug problem

Steve Borel, LSU AgCenter / Guest Contributor
A chinch bug has white wings that are marked with a triangular black patch in the middle.

The southern chinch bug is a common insect pest in turfgrass throughout Louisiana. These insects favor thick thatch, full-sun exposure and hot, dry weather. They are primarily a problem in St. Augustine grass but can injure other turfgrass species. Nymphs and adults cause injury by sucking sap from stems and stolons. — Injury causes grass to turn yellow, then brown and eventually die. — Injury occurs in scattered patches that can merge together into one large dead area. Adults can spread to new areas by crawling or flying. Most injury occurs in hot, dry conditions in mid-to-late summer.

Use the flush test to determine whether certain insects are present in the lawn. Mix 1 tablespoon of lemon-scented soap per 1 gallon of water. Slowly pour the soapy water onto healthy grass surrounding the injured areas. In wet conditions, drench a 1-square-foot area with soapy water. In dry conditions, drench a 4-square-foot area. Then, for five to 10 minutes, closely watch the area to see if insects come to the surface. Repeat as desired in other areas to better determine insect presence.

One way to reduce insect injury and accelerate turfgrass recovery is to maintain a healthy lawn through proper fertilization and irrigation and regular mowing. Never apply more than 1 pound of nitrogen per 1,000 square feet per application, and always follow soil test recommendations for proper fertility. Irrigate as needed while taking rainfall into account. Mow regularly, but never remove more than one-third of the leaf blade height at one mowing.

Thatch can develop over time and may need to be reduced through vertical mowing. Compaction can form more quickly on finer texture soils and in areas where there is high traffic. Dethatching or aeration need to be performed in late spring to summer when the turfgrass is actively growing. Properly maintaining a lawn through these cultural practices promotes dense and vigorous turfgrass and can increase tolerance to insect injury. Insecticide applications may be required to achieve effective southern chinch bug control. Treat with insecticide if 25 to 30 chinch bugs per square foot are observed during the flush test. Some of the insecticides recommended to treat chinch bugs include: Permethrin, Carbaryl, and Bifenthrin. For a complete list you can visit the LSU AG Center website at