We have reached mid-summer, so producers are encouraged to be on the lookout for stink bugs and their close relative, leaf-footed bugs. This year we have seen increasing numbers of green, brown and, in some areas, brown marmorated stink bugs. Generally stink bug numbers peak during the month of August in field and specialty crops and begin to decline in September.
Stink Bug Feeding Damage
True bugs, like stink bugs, feed with piercing-sucking mouthparts and inject enzymes into their food. This type of extra-oral digestion produces various types of injuries to crops, depending on the crop and the part of the plant attacked. Abnormal plant growth, sunken or raised areas on fruit, and discoloration (Figures 1 & 2) are all symptoms of stink bug feeding.
Fields need to be monitored on a weekly basis to watch for changes in pest populations.
While scouting for stink bugs, also watch for leaf-footed bugs (Figure 3). Leaf-footed bugs are occasionally found on fruiting vegetables and green beans. They are true bugs and feed with the same type of piercing-sucking mouthparts. Their feeding causes damage similar to that of stink bugs. Any leaf-footed bugs found while scouting should be treated as stink bugs.
Leaf-footed bugs are large (about 1 inch in length) and relatively narrow when compared to a stink bug. While their body shape and color are similar to that of a squash bug, their hind legs have a flattened and expanded tibia that is the basis for their common name. They have long antennae compared to stink bugs. Leaf-footed bugs may also be confused with assassin bugs, which are beneficial insect predators, but assassin bugs generally have enlarged front legs to capture and hold prey.
Beneficial Stink Bugs
Not all stink bugs are bad. We have three species of beneficial stink bugs that can be common in some fields: anchor bug (Figure 4), two-eyed stink bug (Figure 5), and spined soldier bug (Figure 6). These predaceous stink bugs don’t feed on plants; they dine on insects, including many types of insect pests.
Managing Stink Bugs
Stink bugs are difficult insects to control with insecticides, so when they are a problem select insecticides that are recommended for their control. Occasionally leaf-footed bugs may need to be controlled, particularly on tomatoes where they cause cloud spots under the skin similar to stink bugs. Insecticides that are listed for stink bug control in Vegetable Production Guide for Commercial Growers (ID-36) are recommended for leaf-footed bugs.
Ric Bessin, Extension Entomologist