Controlling Lawn Insects: Chinch Bugs

The adults are small, black bugs 3/16" long with white wings and reddish legs. The nymphs are smaller than adults, wingless, brick red in color with a white band on the back.
The damage is irregular shaped yellow patches, 2 to 3 feet in diameter, which turn brown and die out. Non-grass plants may survive in the affected area. The insects keep moving out from the infested area so are most likely to be found at the edges of the spots.

Chinch bugs are usually not serious on well watered lawns so watering properly will help control them. Severe infestations will require applications of Aspon, Carbaryl (Sevin), Chlorpyrifos (Dursban), or Diazinon. Apply the chemicals according to label directions. Apply pesticides in late April to control overwinter adults, early to mid- June to control first generation nymphs, or in mid-August to control second generation nymphs.

Bluegrass Billbug

Adult billbugs are dull gray to black or brown beetles with a snout or bill. The wings are scaly textured but the insects seldom fly. The larvae are white, humpbacked grubs with a yellow to brown head.

Symptoms are irregular patches of dead grass, especially near sidewalks or curbs. The dead grass pulls out easily and has hollow stems. The larvae are present under the grass and brown sawdust-like frass is present in the root zone. The adults can be found in the grass near the dead areas.

Apply controls for adults in late April or early May before egg laying begins. Larval controls should be applied in mid to late June or July when early injury may be apparent. Use properly labeled formulations of Carbaryl (Sevin) or Diazinon.

Sod Webworm

The larval stage causes the damage. The larvae are grayish brown to dirty white and have 4 parallel rows of dark brown spots on the abdomen. The adults are grayish tan moths that fly in a zig-zag pattern in the evening.

The symptoms are brown patches where the grass blades are missing and not simply dead. The larvae can be found in silk-lined tubes they have made in the thatch layer.

Apply controls between June 10 and 20 or August 10 to 20, depending on which generation is causing the damage. Use acephate (Orthene), Aspon, carbaryl (Sevin), chlorpyrifos (Dursban), or Diazinon according to label directions.

White Grubs

White grubs are the larval stage of one of several beetles. The most common white grub seen in the soil is the C shaped larvae of the May or June beetle. These larvae feed on the grass roots and when numerous can cause dead areas in the lawn.

Symptoms are dead areas in the lawn. The grass in the affected area can sometimes be easily pulled out. Roll back a section of sod to see how many grubs are under the lawn. If many grubs are found, controls may be necessary.

Use properly labeled formulations of chlorpyrifos (Dursban) or Diazinon according to label directions.