Grass blades are eaten in patches, often beginning at the edges of the lawn. The patches may spread until most of the lawn is affected. A brownish paste covers the ground in heavily infested areas. Legless, brownish-gray grubs, about 1 inch long, may be found just under the surface. Late the previous summer, many European crane flies-long-legged, mosquitolike insects-were present around the house. Adult crane flies do not sting or do any other damage. They lay eggs in lawns, and grubs that hatch from the eggs feed on grass blades. The most severe damage occurs in March and April.
The grass is rarely killed in damaged areas, and it usually recovers after feeding stops.