Squash Bugs Description Adults are oval, and dark brown to black. Their abdomen is flattened and covered with fine, dark hairs. They give off an unpleasant smell in self-defense. The youngest nymphs are pale green, while the older ones are covered with what looks like a grainy gray powder. Squash bug eggs are shiny yellow, turning brick red as they mature, and are laid in groups on the undersides of leaves. Where they live You'll find squash bugs throughout North America. Their life cycle Female bugs lay eggs in spring. The eggs hatch in 1 to 2 weeks, and the nymphs take 4 to 6 weeks to develop. Adults overwinter under garden debris, vines, or boards. Squash bugs produce one generation a year. Plants they attack These pests prefer cucumbers, melons, pumpkins, squash, and gourds. Why they're a problem Both adults and nymphs suck plant juices, which causes leaves and shoots to blacken and die. Severely attacked plants may not produce any fruit. Organic damage control Plant resistant squash varieties. Handpick eggs, nymphs, and adults from the undersides of leaves. Support vines off the ground with trellises. Tachinid flies will parasitize up to 80 percent of squash bugs in a given area. The flies, which are found throughout most of the United States, lay their eggs on the squash bugs, then their lavae emerge inside the body of the squash bug. Don't kill any squash bugs that you notice carrying little white eggs since the eggs will hatch into more tachinid flies. Attract the adult flies by planting dill, parsley, sweet clover, fennel, buckwheat, goldenrod, wild carrot, or amaranth. Remove overwintering sites by cleaning up the garden in fall. Protect young seedlings with row covers until the plants are large enough to sustain some damage and still produce a crop.