June 25, 2009 at 8:51 a.m.
The squash bug is common throughout the United States. It will attack all members of the cucurbit family but are most common on pumpkins and squash. Their piercing and sucking mouthparts feed on the plant foliage, and late in the season they may also feed on the fruit. Evidence of the damage includes wilting leaves that will appear black or dried out.
The squash bug looks a lot like the stinkbug bug, but believe me, they are a lot more harmful. They are usually gray to black with the edges of the abdomen having orange and brown stripes. Nymphs are three-sixteenth to one-half inches in length. The young have a red head and legs with a green abdomen; however as the young age the red color will turn blackish grey.
The eggs are one-sixteenth inch long and have a yellowish brown to brick red color. Eggs are laid individually in groups of up to twelve on the underside of leaves. Each cluster of eggs is usually laid in a characteristic V shape pattern following the leaf veins. Eggs are laid from spring to midsummer and will take from one to two weeks to hatch. The eggs will become darker as they get close to hatching.
The adults overwinter and find shelter during the early fall under plant debris, around buildings, under rocks, etc. They emerge in the spring and fly to the fields and the cycle begins again. Both the adult and nymphs cause damage by sucking nutrients from leaves and disturbing the flow of water and nutrients which cause the wilting. Before wilting yellow specks will develop on the foliage that eventually turn brown. Under heavy feeding pressure, small plants can be killed and larger plants can have severe damage. Squash bugs will also feed directly on the fruit and they have become a serious problem in recent years. In fact the gardeners that have contacted me claim the squash bugs multiply extremely fast and eat everything growing.
If only a few plants are affected handpicking of the eggs and bug may be enough. Another option is to place shingles on the ground next to the plants. At night the squash bugs will go under the boards and can be destroyed in the morning. Using resistant varieties such as Butternut, Royal Acorn, or Sweet Cheese and maintaining a healthy plant through proper fertilization and watering are important.
If you have a severe problem, few if any organic controls will work. Insecticide has been effective and you may need to apply more than once. Again, read the label and use recommended amounts. For more info on this or any other Yard & Garden topics, please call the Chisago County Extension Office at 651-213-5430 or 651-213-8905 to leave a voice mail message. You can also visit our Monday night Plant Clinics from 4-6 p.m. at the Extension office at the North Branch Senior Center - 38794 6th Ave. Master Gardeners will be on hand to view your plants sample and answer questions.