Squash Bug

squash bug eggs, nymphs and adults
Squash bugs: eggs, nymphs, and adults

These brownish, gray or black bugs suck juices from the leaves and stems of plants, causing them to wilt, dry up, and turn black. Squash bugs attack all types of squash plants and can also damage cucumber plants.

Adult squash bugs are approximately 1/2" long, with a broad, flattened back. Nymphs resemble adults but are smaller and lighter in color with black legs. Adults and nymphs are often present at the same time. Adults overwinter in plant debris or in the soil, and typically emerge in early summer about the time that vines begin to "run." They lay clusters of reddish-brown eggs on the undersides of leaves. There are one to three generations per year, depending on the region. Squash bugs are found throughout North America.

Prevention and Control

  • Protect newly emerging plants with garden fabric. This material will prevent adult squash bugs from laying eggs. Remove the fabric when flowering begins.
  • If plants are uncovered, scout for egg clusters and destroy them. Handpick adults and nymphs and dump them into a container of soapy water.
  • Spray plants with Neem Oil, an organic, multipurpose pest control derived from the seed of the neem tree.
  • Encourage beneficial insects such as parasitic flies.
  • Lay boards flat on the soil in your garden in the evening. Squash bugs will hide underneath overnight. Lift the board first thing in the morning and collect and destroy hiding bugs.
  • After harvest, remove plant debris from the garden to help reduce the following year's pest population.

Last updated: 03/15/2024