Here is Lesson 8 "Grubs and other Insect Pests" in our Lawn Challenge Series from the University of Illinois. terry
Grubs & Other Insect Pests
Sod Webworm Problems in Lawns
Sod webworms feed by clipping leaf blades off close to the soil surface. Heavy feeding will cause irregular brown areas of grass stubble. The sod webworm larva, which is actually a caterpillar, can be difficult to find as it readily hides in thatch and debris. The adult, which does not feed, is a small whitish moth that will only fly a short distance when disturbed. At rest, the moths fold their wings back over their body and appear tubelike. Adult moths lay eggs by dropping them over the lawn.
If lots of sod webworm moths are observed in the evening, watch for damage in about 10 to 14 days. Early August is typically when we see the heaviest damage, although sometimes damage is also heavy in June. Insecticides should be applied to the surface of damaged areas. Suggested insecticides for homeowners to use on lawns being damaged include carbaryl (Sevin);and Steinernema carpocapsae (Biosafe)nematodes.
Ants in Lawns
Ants occasionally appear in large enough numbers in the lawn that control is needed. The ants may not be actually damaging the grass itself, but the tunneling into the soil may be creating problems. Contact your local Extension office for pesticide recommendations.