Copyright 2010-2011 Updated December 9, 2011 Ultralawn, Inc. 1055 East 260th Street Euclid, Ohio  44132 (216) 731-7756 (440) 951-3738 About • Lawn Care • Trees/Shrubs • Pest Barrier • Questions • Contact Lawn Pests   We welcome the opportunity to answer your questions Sod Webworm   Description: The adults are beige colored moths, which are approximately ½ - ¾ inches long. They sometimes have a small, dark line on the top of each wing cover. Two small finger like projections are visible at the front of the head. Adults will fly upward when disturbed by movement ex. a person walking by, a mower approaching, and will move a short distance before darting back into the grass. The caterpillars are the stage that actually damages turf grass reach up to 1 inch in length when fully grown, but an eighth of an inch long at the beginning of their development. The color is greenish, graying or brownish, and usually have dark spots scattered along the body. Life Cycle: Most species spend the winter as large caterpillars in tent-like structures, which larvae weave to provide extra protection against temperature extremes, a few inches below the surface of the lawn. When the caterpillars become active again in the spring, they feed for a short period before pupating and emerging as moths. Female moths will fly around just above the surface, popping out individual eggs as they fly. The eggs, which land in the turf, hatch about a week later into small caterpillars. These begin feeding almost immediately, on the leaf tissue above the thatch. Caterpillars will go through between six to ten molts as they feed and grow. Eggs, small caterpillars, large caterpillars, pupae and adults can be found at any given time in turf grass in July through September.   Damage:   Sod web worms feed on a variety of grasses. While they often thrive on lush, healthy grass. Web worms commonly attack Kentucky bluegrass, perennial rye grass, fine fescue and creeping bent grass maintained at a variety of mowing heights. Web worm damage starts as small yellow or brown patches in the leaf blades in lawn areas. As the caterpillars feed and grow, the patches gradually increase in size. Caterpillars are nocturnal, so they will not be noticed on the surface during the day. However, when pulling the turf blades apart, gently checks the outskirts of damaged areas, you should be able to find a caterpillar. By midsummer, large sections of the lawn may be destroyed by the sod web worm caterpillars, which prefer sunny areas. Web worm damage is particularly severe in drought conditions, in part because the turf is less able to recover from caterpillar feeding. Damage is usually most apparent in July through September, when temperatures are highest and cool season grasses are not growing vigorously. Affected areas recover slowly from web worm feeding. Management: The key to successful control is to apply an insect control when most of the caterpillars are still young. The insect control should be watered in lightly, just enough to move the insecticide off the blades and into the upper thatch. If possible, the area should not be mowed for two days after application.