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The Lawn Corner: Chinch Bugs

Posted: May 9, 2015

With warmer weather quickly arriving, it will not be long before all types of insects start to appear. Though most of these insects are beneficial or little more than a passing nuisance, the hairy chinch bug can spend the summer severely damaging even the healthiest home lawn.
Image by Paul Heller, PSU Dept of Entomology

Image by Paul Heller, PSU Dept of Entomology

The adult chinch bug is about 1/6-inch long and has a gray-black body, white wings, and reddish legs. The wings have a small black, triangular spot and fold flat over the insect’s back.

The adults overwinter in leaf litter and dense thatch where they are protected from the cold weather. When spring temperatures reach 50°F, the adults emerge and immediately start to mate and lay eggs. After one to two weeks, the eggs hatch, and brick-red nymphs, each about half the size of a pinhead, appear. The nymphs feed throughout the summer, eventually developing into adults and laying eggs in late August. A second generation then hatches in September through October.

Chinch bugs feed on many of the turfgrass varieties common to Pennsylvania, including red fescue, perennial ryegrass, and Kentucky bluegrass. They remove fluids from the grass and inject a toxin which eventually causes the grass to yellow, then turn red-brown, before eventually dying. They prefer grass in full sun and hot, dry weather. Consequently, chinch bug damage is most noticeable during the summer when large patches of dead, brown grass form.

To identify chinch bugs, inspect healthy grass adjacent to dead grass. Driving a gallon sized can with both ends removed into the soil, filling it with water, and stirring the thatch layer will loosen the chinch bugs and cause them to float to the top where they are more easily identified. When more than 15-30 chinch bugs are found in a square foot, treatment is often required.

Since chinch bugs require the protection of thatch, especially in which to overwinter, remediating excessive thatch can help control their numbers. Planting endophyte-enhanced turfgrass varieties, which naturally contain beneficial fungi, will also repel chinch bugs. The chinch bug also has a natural predator called the big-eyed bug, which though similar in size and appearance to the chinch bug, can be easily identified by the large protruding eyes which give the insect its name. When chinch bug populations are excessive, and the cultural and biological controls mentioned above are not sufficient, most conventional insecticides can be used to reduce their population.

Jason Kilgore, Luzerne County Master Gardener