They may be small, but chinch bugs can cause great injury to your lawn. They attack all kinds of turf grasses, and their feeding damage starts off looking like mere spots in your yard that just need a good watering. As the insects continue feeding, these lawn patches turn brown and enlarge. Soon you’ll discover that watering does little to help your grass.
Lawn-lovers look out: You don’t want to see this guy on your grass!
Photo Credit: ©2007 Buglady Consulting
Chinch bugs are related to insects like boxelder bugs and stink bugs, but they’re considerably smaller – adults reach a total length of just under 1/5 of an inch (around 4 mm). Nymphs are about the size of a pinhead after emerging from eggs and are rather striking in appearance: They’re bright red with a white band around their body that looks a bit like a belt. As they grow, the nymphs lose this bright color and begin to resemble the adults, which have white wings that are quite noticeable when held against their black bodies.
Both chinch bug nymphs and adults feed on turf and have mouthparts that allow them to pierce the plant and suck the juices out. This, in turn, blocks the vessels that transport food and water through the plant, causing wilting and discoloration – and potentially death. Damage is often first noticed along the edges of lawns, especially near sidewalks and driveways.
If you suspect chinch bugs are attacking your grass, get down on your hands and knees and look for the insects wherever the brown grass interfaces with green. Another method is to cut the bottom off of a coffee can, push the can into the soil a little ways, fill it with water, and look for chinch bugs that float to the surface. The threshold for taking action to manage chinch bugs is 20-25 pests per square foot.
While you’re looking for chinch bugs, look for predatory insects as well. (Don’t discount the importance that predators may have on reducing chinch bug populations!) The most common chinch bug predator is the big-eyed bug, an insect that looks similar to its prey. Also look for earwigs and spiders. Predators may help keep chinch bug populations down if you leave them alone, but if the pest population increases or if lawn damage becomes severe, you may want to consider applying an insecticide. You don’t necessarily have to treat your entire lawn – just the damaged areas and a buffer around it. (Be sure to read and follow all label instructions carefully!)
Of course, the best defense against this dreaded pest is to prevent it from visiting at all by having a healthy lawn from the start. Avoid excessive soluble nitrogen applications that promote succulent growth, and avoid dry spots by providing adequate irrigation.