Squash bug
Grey-brown shield-shaped bugs that suck sap from squash and pumpkin leaves, causing wilting and blackened leaves, common across the US.
Also known as: Anasa tristis
Symptoms and identification
Leaves develop yellow speckles, then wilt, turn black and crisp. Groups of grey nymphs and adults cluster under leaves and at the base of plants, with bronze egg clusters on leaf undersides.
Causes
Adults overwinter in garden debris and emerge in spring to lay eggs on squash plants.
Organic treatment
Hand-pick bugs and scrape off egg clusters. Lay boards near plants overnight and collect the bugs underneath in the morning. Insecticidal soap kills young nymphs.
Prevention
Use row covers until flowering, clear debris in fall, and grow resistant varieties such as butternut.
Chemical treatment (use with care)
Use an insecticide labelled for squash bugs, targeting nymphs, and avoid open flowers.