Armyworm
Armyworm caterpillars are incredibly voracious as they feed on turfgrass lawns. Normally mid- to-late July is when you start seeing armyworms. They can be found until the first frost; drought years are worse than others.
When & What to Look For
Your first sign of a fall armyworm infestation might be several birds clustered on a turf area. Young worms are 1/2 to 3/4 inch long. Mature ones are 1 1/2 inches long. They are dark colored and have several light stripes down the length of the body. The head or “face” has an inverted “Y” on it.
Life Cycle
The armyworm caterpillars hatch from eggs in 2-3 days, depending on temperature. Once mature, they burrow into the soil and 14 days later emerge as moths. There can be as many as 4 generations of fall armyworms present in one year.
Fall armyworms are attracted to lush, green, well fertilized turfgrass, i.e. fresh sod. The worms rarely kill grass but some plots maybe severely weakened and drought conditions do not help.
Sevin, Dursban, Orthene or Conserve are effective insecticide treatments. Please be sure to read the label carefully and follow the directions.
Water before treating, to move the caterpillars out of the thatch. Treat in the late afternoon, when the caterpillars are likely to begin feeding. If possible, mow before you treat and then do not mow for three days after treatment.
Insecticide Treatment
Sevin, Dursban, Orthene or Conserve are effective insecticide treatments. Please be sure to read the label carefully and follow the directions.
Water before treating, to move the caterpillars out of the thatch. Treat in the late afternoon, when the caterpillars are likely to begin feeding. If possible, mow before you treat and then do not mow for three days after treatment.
