Greg Grant

Chinch bugs are a common pest of St. Augustine grass and often cause significant damage or death during the hot summer months.

Typical damage looks like drought stress, but it doesn’t respond to watering. While St. Augustine grass is the only turfgrass to suffer severe damage from chinch bugs, they can also feed on centipede grass, zoysia grass, and Bermuda grass. However, feeding on these grasses usually occurs only when they are grown next to St. Augustine grass, and the damage on them is typically minor. Chinch bug damage is almost always in full sunny areas next to the reflected heat of sidewalks, walls and streets.

Chinch bugs go through gradual metamorphosis, changing from eggs to nymphs to adults. The adult chinch bug is one-eighth to one-tenth of an inch long with a black body and white wings. The wings fold over the body giving somewhat of a silver X appearance. During the winter, adults are the most common life stage, but nymphs and eggs can also be present in small numbers. Chinch bugs go through five life stages (instars). Though small, the nymphs and adults are visible to the naked eye. After nymphs have matured, adult chinch bugs spread primarily by walking but can also spread through mating flights. After mating, females lay their eggs into the crevices of grass nodes and at the junctions of grass blades and stems. Eggs take approximately two weeks to hatch depending on the temperature, at which point the life cycle begins again. When present in the turf, chinch bugs of all life stages can be found in the thatch and at the base of plants. They damage the grass by feeding on its sap and injecting a toxin that kills the plant tissue. If left untreated, chinch bug damage can cause irregular yellow patches that may spread outward and ultimately kill the turf.

One factor that makes chinch bugs particularly difficult to control is that they hatch quickly and mature in four to six weeks. In Texas there can be as many as three to six generations each year. A number of active ingredients can effectively control chinch bugs, but timing the application correctly is a key to success. Many insecticide product labels state they should be applied before the eggs hatch, when first instar nymphs are observed, or when damage first appears. Therefore, it is important to scout for chinch bugs before significant damage occurs. You can do this by pulling back the turfgrass canopy and looking for nymphs and adults at the edges of damaged and undamaged areas. If chinch bugs are present and causing unacceptable damage, apply an appropriate insecticide as soon as possible. Many products that are labeled for chinch bugs recommend watering the product into the turfgrass canopy. This watering maximizes control by placing the active ingredients into direct contact with the chinch bugs. Always consult the product label for specific instructions on application rates, methods, timing and safety.

For more information on growing lawns in Texas, visit aggieturf.tamu.edu. You can also follow the Texas A&M turfgrass program on Facebook by searching for “Aggie Turf.”

Greg Grant is the Smith County horticulturist for the Texas A&M AgriLife Extension Service. He is author of “Texas Fruit and Vegetable Gardening” and co-author of “Heirloom Gardening in the South” and “The Rose Rustlers.” You can read his “Greg’s Ramblings” blog at arborgate.com, his “In Greg’s Garden” in each issue of Texas Gardener magazine (texasgardener.com) or follow him on Facebook at “Greg Grant Gardens.” More research-based gardening information from the Texas A&M AgriLife Extension Service can be found at aggie-horticulture.tamu.edu and plantanswers.com.