St. Augustinegrass lawns and hot summer days combine for an ideal environment for chinch bugs. These tiny insects are somewhat unique in that they prefer the hot sunny areas of the lawn over shade. Their injury symptoms generally appear in the open lawn areas first.

The adults of this insect are only about 1/5 of an inch long. They are black with what appears to be a white X across their backs where their wings fold over. The immature nymphs may be pink to brown with a single white line across their backs. Chinch bugs have piercing/sucking mouthparts that they use to feed on the stolons and crowns of the turf. They also inject a toxin into the plants and, under heavy infestations, the lawn will turn yellow to brown and eventually die if the insects are not controlled.

To find these tiny insects you will need to part the turf canopy to the soil surface along the border where there is a change from damaged yellowing turf to healthy green turf. Chinch bugs move rather quickly, so keep an alert eye for their scurrying back into the turf.

Another way to scout for them is by cutting both ends from a large gallon size can, twisting it into the turf a couple of inches until it will hold water, then filling it with soapy water. In a few minutes, if present, the chinch bugs will begin swimming on the surface. Carbaryl, bifenthrin, cyfluthrin, lambda-cyhalothrin and permethrin are labeled insecticides for their control.

While chinch bugs prefer St. Augustinegrass lawns, other turf species may be encountering other insects now such as Fall armyworms, white grubs, billbugs, and sod webworms.

To learn more about these insects, their injury symptoms, how to locate and identify them, and insecticides for their control refer to Extension publication #2331 Control of Insect Pests in and Around the Home Lawn. This publication can be downloaded or obtained from your local Extension office.

Published August 8, 2011

Dr. Wayne Wells is an Extension Professor and Turfgrass Specialist. His mailing address is Department of Plant and Soil Sciences, Mail Stop 9555, Mississippi State, MS 39762. wwells@ext.msstate.edu