Last week, a homeowner called concerned about insects in his lawn. They had installed new sod during the dormant season last winter, but were now overrun with tiny bugs, primarily around the edges of the sod. Those areas were beginning to show patches of discoloration and decline. I was able to head out and take a look, and it was the largest case of chinch bugs I’ve seen in my Extension career.
Chinch bugs are tiny insects responsible for a large amount of turfgrass damage. They feed by inserting their mouthparts into grass blades and sucking out plant fluids. While they tend to attack St. Augustinegrass most aggressively, other turf species such as zoysia, bermudagrass, and centipedegrass can also be affected. Chinch bugs are small, roughly 1/5 inch long, or about the size of a grain of rice. Nymphs, or immature chinch bugs, are reddish with a white band across their backs, while adults have lighter-colored bodies with distinctive black patches on their wings. Eggs are laid in the sheaths of grass leaves, and it takes approximately 6–8 weeks for chinch bugs to develop from nymphs to adults.
Damage from chinch bugs typically appears as spreading patches of wilted, brown grass. However, it is important to remember that not all brown or dying turf is caused by these pests, and there are many other potential causes of turfgrass decline. Chinch bugs are most likely to become a problem during hot, dry weather, especially in areas of the lawn that receive full sun. Shady, cooler, or consistently moist areas are generally less susceptible.
These insects are often easiest to find at the edges of damaged turf. One identification method involves pushing a hollow can 2–3 inches into the soil in an area of suspected infestation, filling it with water, and keeping it full for 5–7 minutes. Chinch bugs will float to the surface and can then be counted. A population of 20 or more chinch bugs can cause significant damage to a lawn. Alternatively, you can use a vacuum along the edge of the damaged area, then dump the collected debris onto a white sheet of paper and inspect it for chinch bugs.
Chinch bug problems can occur at any time but are most common in stressed turfgrass. Best management practices depend on your grass species, but in general, avoid mowing lawns too short, avoid fertilizing during periods of hot, dry weather, and be mindful of irrigation practices. If you do have a chinch bug infestation, chemical control may be appropriate, though it should be approached carefully since many chinch bug populations are becoming resistant to insecticides. Be sure to select a pesticide labeled for both chinch bugs and your turfgrass species. If chinch bugs are a recurring problem, rotate the insecticide mode of action you use from season to season to help reduce the risk of resistance.
Early detection and proper management can go a long way toward preventing chinch bugs from turning a small problem into widespread turfgrass damage. If you’re having trouble with your turfgrass this summer, feel free to contact us at uge3181@uga.edu or 706-359-3233 for assistance.
