At the larval stage, the sod webworm measures 1 inch in length when fully developed but they started out small with only 1/8 long. The color and patterns vary with the species and host plant but majorities are gray, green and brown in color with few dark spots on the surface of its body. Its head capsule is light brown with some dark marks.
A full-grown moth is 1/2 to 3/4 inches long with a small dark line on top of each wing. When the adults are resting, they have the habit of folding their wings around its body. When disturbed they fly in a zigzag direction in short distance before going to the grass again.
Sod webworms spend their winter in the thatch which the larvae created to keep them protected against the cold temperature and it’s mostly situated few inches below the surface of the lawn. They will become active again in April or early May and continue to feed before becoming pupae and developing into moths.
Unlike most lawn and crop pests, a female sod webworm flies above the surface popping out eggs as they move. The eggs are dropped on the grass and hatch in larvae after a week. They will start feeding quickly on the leaf tissue of grass. The larvae go through 6-10 of molting as they develop. Since there is a huge number of webworm species and because the climate is different from one place to another, there is a difference in the growth of sod webworms.