Armyworm caterpillar larvae have stripes running the length of their body. One strip is present on each side and another stripe runs down the middle of the back. They are hairless caterpillars having a base color ranging from yellow-green to a dark brown or gray color. Fall armyworm larvae will also have stripes, but differ in having a yellow-white “Y” marking on the head and four dark circular spots on the upper side of each abdominal segment.
Range from 1/16-inch as the first instar larvae to 2-inches as the mature larvae.
Armyworms pass the winter as partially grown larvae in the soil or under debris in grassy areas. Activity and growth are continuous except during very cold weather. When fully grown, they stop feeding for four days and then pupate over a 15 to 20 day period. Adults emerge in May and June.
Females feed for 7 to 10 days on honeydew, nectar, or decaying fruit before laying eggs. Eggs are laid at night in clusters of 25 to 134 on grass or small grain leaves. A single female may live as an adult for 17 days and produce up to 2,000 eggs.
Armyworms have a very broad host range including important vegetable, fruit, field, and ornamental crops. Vegetables commonly injured are beet, cabbage, carrot, collard, cowpea, eggplant, okra, pepper, potato, sweet potato, tomato, and watermelon. Other crops damaged include avocado, citrus, peanut, sunflower, velvet bean, tobacco and various flowers.
Plant damage is nearly identical to the damage caused by Sod webworms. However, Armyworm damage proceeds at a faster rate because of the large sized caterpillars, synchronous egg laying, and subsequent population growth.
Armyworms are actually used to make wine in some parts of the world.
Do you live in South Florida and think that this pest may be invading your yard? Hulett Environmental Services offers specialty lawn care treatments designed to control and eliminate this pest!