Summer vegetable production is nearing its peak and we are seeing a lot of stink bug activity as well. Stink bugs feed with piercing-sucking mouthparts and can be direct pests that attack and damage the parts of the plants we intend to use or sell. Producers need to be watching for our native stink bug pests and two new invasive stink bugs.
Recognizing Stink Bugs
Stink bugs are recognized by their shield shape and the odor they produce when disturbed. Often persons working in the field can smell the presence of a stink bug before they spot it. There are several stink bugs that are serious pests of vegetables including harlequin bug, brown stink bugs (a three species complex), green stink bug, and brown marmorated stink bug. Kudzu bug is one of our newest invasive pests and will be a bean pest once populations build.
Brown stink bugs (Figure 1) and green stink bugs are quite common on a large number of plants and are generally fruit feeders in vegetables. They can be a serious pest of okra, tomato, pepper, and beans. There are actually three species of brown stink bugs that vary a bit in size but can cause similar types of damage to vegetables.
Harlequin bug (Figure 2) is an orange and black stink bug that feeds on leaves of crucifer crops.
Recognizing Stink Bug Damage to Produce
Producers and pickers should to be aware of how stink bug damage appears on their produce. While feeding, stink bugs inject enzymes in the plant. In the case of peppers and tomatoes, areas around the feeding sites fail to color properly, resulting in discolored hard areas underneath the fruit skin (Figure 3). With harlequin bug on crucifers, feeding sites on the leaves will have fan-shaped discolored spots.
Managing Stink Bugs
Thresholds for determining when to spray are limited for stink bugs and these insects are difficult to scout for in vegetables. However, a threshold of 0.5% to 1% damaged fruit has been used as an action threshold for stink bugs on tomatoes. Some of the pyrethroids and neonicotinoids provide good control of stink bugs on vegetables. Refer to Vegetable Production Guide for Commercial Growers (ID-36) for a listing of specific insecticides for stink bug control on various vegetables.
By Ric Bessin, Extension Entomologist