What is a sod webworm?
A sod webworm is the larval stage of a small moth that feeds on grass blades and thatch in lawns, causing brown patches and dead turf. These pests are especially problematic in warm, humid climates like Florida.
Sod webworms are the caterpillar larvae of small moths in the family Crambidae. In Florida lawns, these pests hide in the soil and thatch layer during the day, then emerge at night to feed on grass blades. As they consume turf, they create irregular brown patches and bare spots that spread across otherwise healthy lawns. The feeding damage resembles that of chinch bugs or armyworms, making identification important for choosing the right treatment.
The warm, humid climate of Florida creates year-round conditions favorable for sod webworm populations. Multiple generations cycle through annually, with peak damage often visible in mid to late summer when larvae are most active. Homeowners may first notice the problem when birds start foraging in the lawn for the larvae, or when distinct irregular patches of dead or dying grass appear without other obvious causes.
Professional pest control programs address sod webworms through targeted insecticide applications timed to larvae feeding periods, combined with monitoring techniques to detect infestations early. Some programs also recommend adjusting irrigation and lawn maintenance practices, since healthy, well-maintained turf resists pest pressure better than weak grass. Regular lawn inspections help catch populations before they cause significant damage.