University of Maryland Extension

Stink Bugs - Vegetables - Fruit

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Dealing with stink bugs in vegetables and fruit 

stink bug adult 
Adult brown marmorated stink bug (BMSB) (Halyomorpha halys)          

 green stink bug adult
Adult green stink bug (Acrosternum hilare Say)

brown stink bug adult
Brown stink bug adult (Euschistus servus)
Photo: Russ Ottens, University of GA, Bugwood.org

Appearance

  • Eggs: light colored clusters of about 25 (up to 60 for brown stink bug), on end, under leaves. Brown marmorated stink bug eggs (BMSB) are elliptical. Others are more barrel-shaped.
  • Nymphs (immature form): 5 instars (developmental stages) flattened like adults, but rounder. BMSB - short strips of red-brown and black. Black and white banding on antenna and around abdomen like adults, plus on legs. Brown stink bug - yellow-brown to brown. Green stink bug - vary from yellow-orange to black, reddish and greenish.
  • Adults:  5/8" shield-shaped bugs. BMSB - mottled brown and cream with black and white banding on abdomen edge and on antenna. Brown - brown. Green - green with white specks.

cluster of brown marmorated stink bug eggs
Brown marmorated stink bug eggs               

 brown marmorated stink bug eggs hatching 
 Brown marmorated stink bug eggs  and nymphs

 eggs and nymphs
Brown marmorated stink bug first instars

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 creates superficial spots (white on young fruit or yellow on mature fruit) known as "cloudy spot" on tomato 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.

stink bugs feeding on tomato     
Stink bug nymphs and adults feeding on      
tomato

stink bugs damaging a tomato
Stink bug damage on Roma tomatoes

stink bug feeding on pepper
Stink bug feeding on and damaging a pepper

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.

kaolin clay sprayed on tomatoes
Tomatoes sprayed with kaolin clay
(a finely pulverized clay, mixed with water)
to help 
prevent stink bug damage

Additional Resources

Video


UME Entomologist, Mike Raupp, offers common sense options for stink bug control

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.

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