This common blackish or earth-colored bug is usually called the squash stink-bug. It has a very disagreeable odor which gives it this name. When disturbed it throws off from scent glands a small quantity of an oily substance which produces this odor. This is a protection to it for few birds or animals care to feed on it. Most species of sap or blood sucking true bugs have a similar protecting odor.
The squash bug feeds largely on squash and pumpkins. It has a slender beak with needle-like mouth parts which are stuck into the plant for extracting the sap. It feeds only on plant sap. When it can not get squash or pumpkins it will feed on watermelons, muskmelons and related crops. It is very destructive to these crops. It not only extracts sap thus weakening the plant but it also seems to poison the plant while feeding. In this way its bite injures the plant something like the effects of the bed-bug's bite on our flesh. It feeds first on the leaves and vines often killing them in a few days. Later it may cluster and feed on the unripe squashes or pumpkins in such numbers as to completely cover them. Every country boy or girl has seen these stinking bugs on pumpkins in the corn field, at corn cutting time in the fall.
The squash bug lives thru the winter as the matured winged insect. It flies from its food plant to winter quarters late in the fall. For winter protection it may enter buildings, hide under shingles on roofs, crawl into piles of lumber, under bark of dead trees or stumps or hide under any similar protection. When its chosen food crops begin to come up in the spring it leaves its winter home and flies in search of food. After feeding for a time the female lays patches of oval, flattened, gold-colored eggs set on edge. When first deposited the eggs have a pale color but in a short time the golden color appears. In some cases only three or four eggs may be found in one patch while again there may be twenty or thirty of them. They are so brightly colored that they can easily be seen and most boys and girls have seen them on the leaves of squashes or pumpkins.
In a few days after they are laid they hatch and out of each crawls a small, long-legged blackish or greenish young bug called the nymph. These little fellows usually stay in a crowd hiding on the under side of a leaf. After feeding for a time their leaf begins to turn yellow and soon dies. Then they move to a new leaf. As they feed they grow rapidly and after shedding their skins they change to the second nymph stage. This shedding of their skins or molting occurs five times before they mature. Of course each time before the old skin or suit of clothes is discarded a new one is developed beneath. The females may continue to deposit eggs for later clusters of young. They become most abundant on the crop late in the fall. Just before cold weather sets in the adults again seek winter shelter.
This is a very difficult insect to control. Since it feeds on liquid sap only it is impossible to kill it by spraying the crop with a poison such as arsenate of lead. It can not chew and swallow such poison. The young can be killed fairly well with a spray or dust containing nicotine but such treatments are not effective against the adults or nearly mature nymphs. A better method is to destroy all the bugs possible in the fall before they go to the winter protection and then watch for and destroy the adults and the eggs masses in the spring when they appear on the young crop. If the first adults and the eggs and newly hatched nymphs are destroyed the crop can be protected against the destructive work later.