Fall army worms are on the march in Louisiana, and heavy populations are causing major damage to lawns across the state. No lawn grass is immune to their attack.

Fall army worms can have up to four generations per year in Louisiana, and each generation takes about a month to complete its life cycle from egg to adult moth. In epidemic years, heavy moth flights can result in overlapping generations.

The larva or caterpillar stage lasts two to three weeks. The full-grown larvae are about 1-1.5 inches long, brown to green in color, with a prominent, inverted Y on the front of the head. They are called army worms because they move together in large numbers, just like an army.

Large caterpillars can devastate a turfgrass lawn's foliage in just a few days. Areas affected by army worms in lawns may start small but rapidly expand in a few days. Damage resembles major scalping with a weed eater or lawn mower. Grass will grow back, but recovery will be slow. The damaged areas will be more susceptible to disease invasion this fall.

In urban areas, homeowners can treat their lawns when fall army worms threaten turf establishment or survival. Bermuda grass is normally the most susceptible lawn grass. Major infestations and damage have been found in Centipede grass and St. Augustine grass in the past month.

Insecticides recommended for control of insects on lawns are Acelepryn, Azatin XL, Battle GC, Mach 2, Lepinox WDG, Conserve SC, Talstar 10WP, Dylox, Condor XL, Crymax and Sevin.

Contact:
RONALD J. NICHOLAS, SR.
COUNTY AGENT
ST. LANDRY PARISH
Tel: 337-948-0561
E-mail: RNicholas@agcenter.lsu.edu

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