Summer days, St. Augustine lawns, and chinch bugs (7-12-10)

These hot summer days are ideal for your St. Augustinegrass lawn to heal and get healthy from winter injury or spring diseases, but don’t let your guard down just yet as chinch bugs love St. Augustinegrass lawns. The adults of this destructive 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.

Turf injury symptoms are a subtle yellowing of the leaf blades, thinning of the canopy and eventual death of the turf under extreme insect pressure. These insects are somewhat unique in that they prefer hot sunny areas of the lawn over shade so their injury symptoms generally appear in the open front lawn area first.

To scout for these tiny insects in your lawn you will need to part the turf canopy to the soil surface along a line where there is a change from damaged yellowing turf to healthy green turf. They move rather quickly, so keep an alert eye for their scurrying back into the turf. Another way to scout for chinch bugs is by cutting both ends from a large coffee 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 the chinch bugs, if present, will begin swimming on the surface. Carbaryl, cyfluthrin, lambda-cyhalothrin and permethrin are labeled insecticides for their control.

While chinch bugs prefer St. Augustinegrass lawns, other turf species may also be encountering 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 Control of Insect Pests in and Around the Home Lawn. This publication is also available from your local Extension office.

Published July 12, 2010

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. [email protected]