What are these caterpillars in my yard?
Caterpillars are some of the most destructive pests in turf grasses in the Fall. The sod webworm (green in color) and armyworm (distinguishable by the “Y” marking on their head) are two types of caterpillars that we often see here in the Lowcountry in late summer through fall.
Sod Webworm
Green in color, sod webworms can cause excessive damage to turf grasses. They prefer hot, dry grasses; particularly steep slopes and banks. These worms feed on grass leaves during dusk and at night. The initial symptoms of sod webworms in a turf grass are yellow and brown patches, similar to drought signs. Other signs of sod webworms may be groups of birds feeding and flying over turf grasses, as they feed on the larvae and brown moths that will fly low in a zig zag pattern over the grasses before laying eggs.
army worm
Army worms are distinguishable by the “Y” marking on their head. Feeding primarily in the early mornings or late evenings, army worms often leave behind a sawdust-like substance after they chew through the grass blades. Their moths lay eggs near tree lines and as caterpillars hatch, they move outwards towards the grass to feed.