Pest Name: Armyworm
Background: Armyworms are so named because they invade in large numbers like a battalion of plant-eating soldiers, leaving a path of lawn death and destruction behind them. Armyworms destroy grass by nibbling the blades down to the nub. Once they have devoured the lawn, they will move on to ornamental plants. Armyworm caterpillars are the larvae of armyworm moths, and several species affect lawns across the U.S. Armyworm larvae typically measure 1-1/2- to two inches long; vary in color from green to brown or black; have green, yellow, red or brown stripes down their sides and backs; and sport a distinctive inverted “Y” mark on their heads.
Damage: Armyworms eat the lawn down to the ground, leaving large areas of dead grass or even bare dirt. The damage occurs very fast.
Monitoring: Frequent inspection is important. Look for large, expanding areas of dead grass or bare dirt. In the areas, large quantities of the Armyworm will be present. Armyworm grubs attract birds, skunks and rodents that feed on the larvae, so large numbers of scavenging birds or scratched areas of lawn may indicate a plentiful armyworm population.
Treatment For Armyworm: There are several options for treating Armyworm:
Chemical Controls: Just about any general pesticide in granular or liquid form that controls turf insects will work on armyworms. If using granular, be sure to water it into the ground.
Organic Controls: Neam and other oils have proven effective as have BT. Ecologic makes a granular organic control that works well too.