Gardening: Plants wilting and dying? It could be the elusive squash bug

Nicole Taylor stopped dead in her tracks. Her zucchini and summer squash plants that were lush and growing a week ago in her community garden plot were now wilted and dying. “What happened? They were good last week.” A quick inspection revealed her plants were covered with squash bugs happily sucking the life out of her plants.

Squash bugs are a problem this year around the area. Our winter temperatures didn’t get cold enough to kill off the overwintering adults, so they got a head start unbeknownst to you. Now they have reached critical mass and are devouring and killing the plants before you can control them.

Squash bugs feed exclusively on summer and winter squash, pumpkin, melons and cucumbers. Adults and nymphs both feed on the plants by sucking the plant’s juices. Leaves become speckled, then wilt as edges turn yellow or brown and quickly die. They may also feed on fruits, leaving scarred areas. The bugs can also carry a virus, cucurbit yellow vine decline, that infects the plant at the same time leading to an even quicker demise.

Adult squash bugs are about ⅝ inches long and ⅓ as wide. They are grayish brown with a flat, shield-shaped back. The edge of the abdomen usually has pale orange stripes or spots. They can be mistaken for stink bugs. However, stink bugs are wider and rounder than squash bugs and emit a noxious odor if disturbed.

Squash bug nymphs vary between 3/16- and ½ -inch long and go through several molts as they grow. They are generally grayish with a crimson head, thorax, antennae and long legs. They may be covered with whitish powder and are wingless. Older nymphs are grayish white with black legs and antennae. The long legs on both the adults and the older nymphs allow them to move very quickly.

Adult squash bugs begin laying eggs as the plants emerge in the spring. The eggs are 1/16 of an inch long, coppery gold-colored and are laid in small groups on the underside of the leaves. It takes about 10 days for them to hatch into nymphs that then take four to six weeks to become adults.

To control the bugs, start by removing or composting garden debris in the fall. This takes away the hiding places for the overwintering adults. Rotate squash crops to new areas of the garden yearly to break the bug’s life cycle.

In the spring, cover new plantings with securely anchored floating row cover to block the bugs’ access to the plants. Remove the cover when the plants begin flowering. Inspect the underside of the leaves weekly and crush any clusters of eggs you find. If the population of bugs remains small, you may be able to manage it by picking off adults and nymphs and crushing eggs.

If there is a large infestation, you can spray the plants thoroughly with insecticidal soap, permethrin-based chemicals or spinosad, neem oil. Pay close attention to the underside of the leaves.