How to Manage Pests
UC Pest Management Guidelines
Several kinds of stink bugs feed on cucurbits, but all are similar in life history and damage. Adult stink bugs are distinctly shield shaped, about 1/2 inch (1.3 cm) long and either brown or green. Some species have red, pink, or yellow markings. Eggs are laid in about fourteen to a cluster and are barrel-shaped with circular lids. Initially they are pearly white and later turn cream colored or pinkish just before hatching. For consperse stink bugs, a row of spines encircle the top of the eggs; the other species have concentric black rings on top of the eggs. Early nymphal stages resemble the adults in shape, but have various markings and patterns and no wings. Nymphs develop prominent wing pads as fourth and fifth instars.
The green stink bug is bright green with the entire lateral margin lined yellow, orange, or reddish. It is slightly larger (0.6–0.9 inch or 1.5–2.2 cm in length) and less common than the redshouldered stink bug, which is predominantly green with a narrow red band across the shoulder, although sometimes the band is absent. Consperse stink bugs have gray brown to green bodies with yellow to orange legs and antennae with darkened tips. The body and legs are covered with small, black specks and the undersurface of the body varies from gray to green. Say's stink bugs have green and yellow colors on the head and back, are covered with tiny white flecks, have three pale spots at the base of the scutellum, and appear distinctly rounded when seen from above. These bugs develop in trees and weeds and move into green plants. Do not confuse these stink bugs with the rough stink bug, a predator that is speckled white and gray and is quite common in many crop areas throughout the year.
Feeding on immature fruit can cause growth distortion as well as irregular surface and internal spots on fruit at any time.
Stink bugs are sporadic and spotty seasonal pests. Adults overwinter on the ground under leaves, in orchards, legume crops, blackberries, or on certain weeds such as Russian thistle, mustards, and little mallow (cheeseweed). During mid- to late summer, populations can become quite high. These pests often move from undisturbed areas such as weedy fields and ditchbanks as well as from riparian areas into crops. Monitor such adjacent areas to eliminate any surprise infestations. Check developing fruit for stink bugs. Time applications after the majority of eggs have hatched and nymphs are easily found. Individuals tend to hide by moving to the opposite side of the plant or fruit surface being observed.
UC IPM Pest Management Guidelines: Cucurbits