Issue 8, July 29, 2020
Chinch Bugs
Chinch bug life stages, David Shetlar, The Ohio State University, Bugwood.org
There are two species of chinch bugs that can cause damage to turfgrass in Illinois, the common chinch bug in southern and central Illinois and the hairy chinch bug in northern Illinois. Both species feed on Kentucky bluegrass, fescues, ryegrass, bentgrass and zoysiagrass. Common chinch bug also feeds on corn, wheat and sorghum.
Common chinch bug and hairy chinch bug are similar in appearance. Adults grow to be about 1/8 inch long but nymphs may be smaller. Adults are black and white, while nymphs have a black and white head and thorax with a reddish-brown abdomen.
Chinch bugs are usually well controlled by fungal pathogens that occur naturally in the environment. But in hot, dry conditions, they can sometimes cause significant injury to turfgrass. These insects suck fluids from the crowns of turfgrass, causing yellowing and browning in patches across a lawn. Infestations are most common in hot, dry weather and in turf that has been well fertilized.
There are two methods that can be used to scout for chinch bugs:
Method 1: Inspect the crowns of turfgrass. Chinch bugs feed at the crowns of the grass plants so that is the best part of the plant to inspect. Begin looking for chinch bugs on healthy plants along the edge of a damaged area. Part the grass with your hands and inspect the crowns of the grass plants for chinch bug adults and nymphs. The nymphs can be quite small so a hand lens or hand magnifying glass can help. In very hot conditions they may move lower on the plant to avoid the heat.
Method 2: Flotation. Because chinch bugs are so small, they can be difficult to identify on the surface of grass plants. The floatation method can be used to separate the chinch bugs from grass and debris, so they are easier to see. To accomplish this, remove the top and bottom surface of an old coffee can, then press the can firmly into the turfgrass. Fill the can part of the way with water and let it sit for 5-10 minutes. The chinch bugs will separate from the grass and float to the surface of the water, where they can be easily seen and identified.
Control: Apply a contact insecticide, such as bifenthrin (Onyx, Talstar), lambda-cyhalothrin (Scimitar), deltamethrin (DeltaGard) or trichlorfon (Dylox), on the surface of the grass. The chinch bugs will consume the pesticide as they pierce the plants to feed.
Author:
Sarah Hughson