Stink Bugs on Vegetables

Lifecycle/habits

• Brown and Green overwinter as adults on weeds, garden debris and under tree bark. BMSB uses sheltered cracks of buildings, rocks, wood piles. Eggs are laid under leaves. Young nymphs aggregate near egg-hatch. Nymphs and adults insert piercing mouthparts and suck plant sap from leaves, fruit, buds or blossoms.
• Southern green stink bug feeding can infect beans with a disease. They hide when disturbed. Adults are strong flyers and secrete a repellant fluid when threatened or squashed. They also emit aggregating pheromone.
•  Annually, there are 3-4 generations of Southern green stink bug, but only one of brown stink bug. BMSB may have up to 2 in Maryland.

Host plants

• Bean, pepper, tomato, as well as corn, eggplant, okra, pea, soybean, squash, plus most other vegetables and fruits.

Signs/symptoms

• Piercing and sucking create superficial spots (white on young fruit or yellow on mature fruit) known as "cloudy spot" on tomatoes and other fruits.
• Pimples or wart-like growths appear on okra and bean pods. Blossoms and pods may drop prematurely. Leaves may roll, wilt, or be stunted. Fruit may be deformed. Corn may increase tillering, silk be delayed, and produce reduced as well as damaged
• Southern green stink bug feeding punctures, introduce seed pit or yeast-spot disease into lima pods, ruining the beans.

Monitoring

• Check leaf undersides for egg masses (see photo above). Remove or destroy any discovered egg masses.
• Watch young plants, then fruit for damage, especially lima pods as they are rendered inedible. Search carefully for stinkbugs as they purposefully hide.  "Healthy" lima beans may reveal cloudy spots when shelled, then grayish blotches when blanched, where bugs introduced yeast disease, Hermatospora coryli, known as seed pit or yeast spot.

Prevention/control

• Clean up plant debris after the season, especially crucifers and legumes. Tilling disrupts overwintering sites.
• Use row cover when possible, beginning in spring.
• Search for egg masses and crush. Handpick bugs.
• Bugs hide or drop when startled. Knock into a container with soapy water held underneath.
• A cloudy spot in fruit can be cut out and does not affect eating quality.
• Insecticidal soap or botanicals such as neem or pyrethrum are only effective on young nymphs. Adults are resistant even to highly toxic insecticides.
• Thick organic mulch provides desirable habitat for stinkbugs. Consider removing mulch or using plastic, fabric or rolled paper mulch.
• Many natural predators and parasitoids are still not enough to control them but conserve beneficial predators by using only insecticides with a short residual.
• Thick-skinned cultivars may provide some resistance.

Additional resources

• Brown Marmorated Stink Bug - Frequently Asked Questions
• Predatory Stink Bugs

In 2010 and 2011, brown marmorated stink bugs (BMSB) were seen in extremely high numbers in the Mid-Atlantic region. They were responsible for causing major economic damage to fruit and vegetable crops at a number of orchards and farms. In addition to causing damage to plants and fruit, brown marmorated stink bugs are a major nuisance to people. Adult stink bugs often seek shelter inside houses and other buildings. Once inside, they congregate almost anywhere. These pests will not cause structural damage or reproduce in homes. They do not bite people or pets. Although they are not known to transmit disease or cause physical harm, the insect produces a pungent, malodorous chemical and when handling the bug the odor is transferred readily.

Additional resources

Common Stink Bugs of the Mid-Atlantic