Sod Webworm

Sod Webworm Overview

Sod Webworms can cause exceptional damages to lawns and parks especially during periods of drought. There are several species of sod webworms and they all look similar. They live in the thatch, above the ground and create webs to feed underside the leaves of the grass. When the leaf is hit and they are disturbed, sod webworms curl up into small balls immediately. Their host plants include Kentucky bluegrass, fine fescue, bentgrass and perennial ryegrass.



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.

Life Cycle

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.


The damages caused by the sod webworm larvae can be determined by brown patches in the grass that is the same size as a baseball. Punctures and few tiny holes can also form as a result of birds searching for webworms. The larvae consume the leaves and stem at the top of the crown. As they continue to grow and feed, damages incurred can be more extensive.


There are several ways to control the infestation of sod webworms; this includes using the insect-parasitic nematodes, insecticides and the soapy water treatment. You can also have your lawn well-watered to decrease thatch and stresses on lawns. If you are planning to use pesticides, read the directions carefully and the safety measures on the label. Another option is calling a pest management professional you can rely on.


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