Are fall armyworms picnicking on your lawn? (08-01-2005)

By the first week of August we should have many mid-summer lawn chores behind us. However, we can’t sit back and anticipate the cooler breezes of fall just yet, or ignore late summer pests during these dog days of summer.

As we approach the end of summer the fall armyworm is one such beast that is lurking to play havoc with our lawns before the first frost arrives. During the last few weeks of the heat of summer the adult moths will fly onto your lawn, mostly at night, depositing up to 1000 eggs each in clusters of about 150 eggs per cluster. Within a few days these eggs hatch. The tiny worms begin feeding voraciously and can devour every bit of green tissue down to the ground.

These worms are not too difficult to control with insecticide applications, but it is important that careful monitoring be done to catch them before they become too destructive.

Scouting is best done by checking your lawn a couple of times a week for ragged torn leaf blades and the presence of the tiny worms. When first hatched they will be only about 1/16 of an inch long and light grayish-green in color. Older ones range from light tan, to olive green to nearly black with stripes along their sides. They will also exhibit an inverted Y-shaped marking on the front of the head.

Published August 1, 2005

Dr. Wayne Wells is an Extension Professor and Turfgrass Specialist. His mailing address is Department of Plant and Soil Sciences, Mail Stop 9555, Mississippi State, MS 39762. [email protected]