The brown stink bug (Euschistus servus Say) is a serious pest along with a number of other stink bug species in the southern U.S. They are found on a wide range of cultivated crops including fruits, grains, nuts, and vegetables as well as a number of ornamentals and broadleaf weeds.
Brown stink bugs can be found across all of southern Canada, much of North America, and throughout the year in parts of the southern U.S.
Adult brown stink bugs are shield-shaped insects, grayish-yellow with dark punctures on their back, and piercing-sucking mouthparts.
The ventral surface usually has a pinkish tinge. The angles of the pronotum are rounded. The body length varies from 1/3 inch to 1/2 inch for adults.
The eggs are yellowish-translucent, but their color starts turning a light pink before hatching.
Brown stink bugs often feed on the vegetative parts (flowers, stems, and foliage) of the plant as well as the seed, nut, or fruit.
Adults are strong fliers and move readily between weeds and other alternate hosts.
Adults feed by inserting their needlelike mouthparts into stems, leaves, and seed pods. While doing so, they inject toxic substances into the plant parts that may cause the structures to abort or inhibit plant development in the area of the punctures.
Penetration by the mouthparts can cause physical damage. A combination of mechanical and chemical damage to the growing point of the plant may be responsible for the injury and symptoms seen in the field. The degree of damage depends on the developmental stage of the plant when it is attacked.
Under drought conditions, the bugs may attack fruit in much higher numbers.
Survival And Spread
Adult brown stink bugs overwinter in protected areas and become active in the spring when temperatures reach 70°F. Normally, the first generation develops on weedy hosts, while the second generation typically develops on cultivated crops.
Each female oviposits about 18 egg masses, averaging 60 eggs, over a period of about 100 days. Roughly four to five weeks are required from hatching to adult emergence. Several generations per year are possible in Florida.
Stink bugs may be controlled with insecticides, but stink bugs are relatively tolerant of many insecticides making suppression difficult. Reduction in pesticide use may have led to a recent resurgence in populations of the brown stink bug.
Practices that eliminate weeds may help minimize stink bug populations.
The eggs and nymphs of stink bugs often suffer high mortality from parasites, predators, and pathogens.
Monitoring can be done by direct examinations and damage ratings. Beating tray sampling, sweep sampling, and using traps with stink bug aggregation pheromone also are ways of monitoring and capturing them.
In organic systems, trap crops may be used to intercept the stink bugs before they enter the cash crop.