Pediasia trisecta

Pediasia trisecta, commonly known as the sod webworm, belongs to the order Lepidoptera and the family Crambidae. This moth species is a significant pest of turfgrass and various cereal crops, particularly in North American regions where it causes substantial economic damage to managed landscapes and agricultural fields.

The host range of Pediasia trisecta includes various species of turfgrass, such as Kentucky bluegrass, fescue, and bentgrass. In agricultural settings, the larvae often infest corn, wheat, and other small grains, especially when these crops are planted in fields that were previously established in sod or infested with grassy weeds.

The life cycle typically consists of one or two generations per year. Larvae overwinter in silken hibernacula within the soil or thatch layer. As temperatures rise in spring, they resume feeding, grow rapidly, and pupate. The adult moths are nocturnal and are characterized by their habit of resting with their wings folded closely against their bodies.

Damage caused by this pest is primarily subterranean and nocturnal. The larvae feed on the blades and crowns of grasses, often creating silken tunnels near the soil surface. Typical symptoms of infestation include irregular brown patches in lawns and thinning stands in field crops, which can lead to complete plant failure if the population density is high.

Effective management strategies combine cultural, biological, and chemical methods. Cultural practices include proper irrigation, adequate fertilization to promote plant recovery, and the reduction of thatch accumulation. When chemical intervention is necessary, targeted application of insecticides during the early larval stages is essential to minimize damage and preserve the turf or crop integrity.