Squash Bug

Anasa tristis — the squash bug — is one of about 1,800 species in family Coreidae (the leaf-footed bugs) and the dominant agricultural pest of cucurbit crops (squash, pumpkin, gourd, watermelon, cantaloupe, cucumber) in temperate North America. Adults are 14-16 mm long, gray-brown, with a flattened body. The species feeds on cucurbit stems, leaves, and developing fruit using stylet mouthparts that inject saliva while extracting sap. The injected saliva contains plant-toxic compounds that cause progressive wilt, leaf necrosis, and eventually plant collapse. Heavy infestations can defoliate and kill mature squash plants within 1-2 weeks. Squash bug is also the primary vector of Serratia marcescens, the bacterium that causes cucurbit yellow vine disease (CYVD) — a destructive wilt disease that has emerged across the US South and Midwest since the 1980s and now causes significant losses in commercial cucurbit production. Egg clusters (typically 15-20 bronze-colored eggs in a regular pattern) are laid on the underside of cucurbit leaves and are the most-recognizable life stage. Hatched nymphs are pale gray-green with red legs and antennae and aggregate near the egg cluster initially. The species is one of the most-encountered and most-loathed pests of organic vegetable gardens in North America. Effective management requires hand-picking egg clusters and adults, row covers during early plant establishment, trap-cropping with sacrificial squash plants, and integrated pest management with selective insecticides.