The squash bug is a small gray insect that is often mistaken for the stink bug. Since these two bugs appear quite similar and both have a distinct offensive smell when crushed, it is not hard to see why their identities might be confusing. The easiest way to tell the difference is to simply remember that the stink bug prefers tomato and legume plants, while the squash bug, as its name implies, is fonder of squash and pumpkin.
Monitor seedlings and flowering squash plants. Eggs are usually 1/16 of an inch in size and have a yellowish-brown or reddish color. They can usually be found underneath leaves in bunches of 12 where they form a "V" shape along the vein line. Once the eggs have hatched, young squash bugs (nymphs) begin sucking nutrients from the leaves where their damage will initially cause yellow specks to appear on the foliage that will later turn to brown. Early detection is the key to keeping the squash bug under control. Check underneath plant leaves regularly for signs of eggs or young squash bugs.
Destroy squash bugs and eggs by hand. Small infestations can be controlled by hand-picking squash bugs and eggs from the plant and dropping them into a container of warm soapy water. Wear garden gloves to protect hands from other insects that may be lurking under leaves and to help with the "ick factor" of pulling squash bugs off the plant.
Place boards or old shingles on the ground near the squash plants. Squash bugs will gather underneath the boards at night and can be easily seen and removed in the morning.
Keep debris from around the garden site. Piles of sticks or rocks make perfect hiding places for the squash bug. Trim weeds and remove items from the garden area that squash bugs may hide under.
Remove squash plants from the garden after the harvest is over. Squash bugs will continue to forage on remaining plants until they are forced to find shelter for the winter. Once squash is no longer growing on the vines, take plants away from the area and dispose.