Distant: Patches of turf turning brown in July or August. The damage resembles drought stress, but turf damaged from chinch bugs does not recover after a rain (Image B).
Up close: Dead and dying grass plants, and small (1/8 inch) black bugs in the surface duff or thatch when it is scratched or parted.
When damage is found: July and August
Host: All grass species including perennial ryegrass, Kentucky bluegrass, red fescue and creeping bentgrass.
Site: Chinch bugs are more likely to be a problem in non-irrigated turf. Sunny areas of lawns, sandy soils, and thatch lawns are most likely to become infested.
Description of damaging stage: The adult stage and large larvae cause the most damage. Adults are 1/8 inch long and have piecing/sucking mouthparts, like a needle, which are inserted into the grass plant to suck sap. Saliva injected into grass plants when the chinch bugs are feeding causes a burn-like reaction. Large larvae are almost entirely black, but adults have wings with angular white markings. Young larvae are smaller and red.(Image C)
Sampling: Use the hands and knees method to look through and under duff and thatch around the base of the grass plants in June and July. Search for 2 minutes in several locations in, at the edge and near the damaged areas. When chinch bugs are found, typically there will be many. The population is often clumped in patches.
Preventing Pest Injury to Turfgrass: Home lawns, recreational turf and golf course roughs can be managed to avoid insect injury without insecticides by using proper fertility, mowing at a height of 3.0 to 4.0 inches, and watering during dry periods. This will build a dense stand of turf and a diverse community of insects that will keep turf pests under control. All lawns in Michigan will typically start off lush and green in the spring and will go dormant and turn brown during periods of little rain. Information on the use of insecticides to treat turf pest problems is only meant to be used for the unusual cases where turf damage from pests becomes unacceptable. Even then, insecticides should only be used in areas of a lawn with severe turf damage, and only until a dense turf is re-established.
Using insecticides: Use insecticides judiciously, temporarily, and only in response to unacceptable turf injury. Mow lawns before spraying or spreading an insecticide to avoid leaving a pesticide residue on flowering weeds, which may be harmful to pollinators. Many insecticides are poisonous if ingested, and therefore must be stored in places where they cannot be found by children. Use the rate recommended on the label for the pest you are attempting to control. Wear rubber gloves, safety glasses (or goggles), rubber boots, long pants and long sleeved shirts when mixing and applying insecticides. The most caution is needed when mixing a concentrated insecticide in water, because skin contact with the concentrated insecticide in the original container is more dangerous than contact with the diluted insecticide after mixing. Water the turf immediately after applying the insecticide to wash it to the base of the plants or into the soil and allow the turf to dry before allowing access by people and pets.
Chemical Control of Chinch bugs: Neonicotinoids (such as clothianidin, imidacloprid or thiamethoxam) can be used for chinch bug control and work best for Chinch bugs when applied in late May or early June. It is not recommended to apply a neonicotinoid for chinch bugs after August 15th. Synthetic pyrethroid insecticides such as deltamethrin, cyfluthrin, bifenthrin, permethrin and lambda-cyhalothrin applied in July when the chinch bugs are active will also work but the lawn will need to be watched closely as this class of chemical is very rough on natural enemies such as predators and parasitoids; and the chinch bug population may rebound quicker than the beneficial insects.