Stink bugs are becoming more numerous as we move into the mid-summer months; they are feeding on a wide range of agronomic and horticultural crops. Producers are encouraged to be on the lookout for stink bugs and their close relative, leaf-footed bugs. While they do feed on foliage of some crops, the more common damage is to the fruiting structures, the part of the plant we would like to sell. We are finding four types of stink bugs attacking crops: green stink bug, brown stink bugs, brown marmorated stink bug, and harlequin bug. Generally, stink bug numbers peak during August in field and specialty crops and begin to decline in September.
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 plant part attacked. Abnormal plant growth, sunken or raised areas on fruit, and discoloration are all symptoms of stink bug feeding.
Monitor Plantings for Stink Bugs and Leaf-footed Bugs
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. Leaf-footed bugs are occasionally found on fruiting vegetables and green beans. They are true bugs and also feed with 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. However, assassin bugs generally have enlarged front legs to capture and hold prey.
Beneficial Stink Bugs
Not all stink bugs are bad. Kentucky has three species of beneficial stink bugs that can be common in some fields: spined soldier bug, anchor bug, and two-eyed stink bug. These predaceous stink bugs don’t feed on plants; they dine on insects, including many insect pests.
Managing Stink Bugs and Leaf-footed 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, green beans, or peaches, where they cause damage similar to stink bugs. Insecticides listed for stink bug control in Vegetable Production Guide for Commercial Growers (ID-36) are recommended for leaf-footed bugs.
By Ric Bessin, Extension Entomologist