I have a peculiar fascination with stink bugs. My affection may be misplaced, however, because some stink bugs are pests of garden plants and fruit trees. One exotic species, the brown marmorated stink bug came to the U.S. recently and the agricultural industry is already on alert.
The adult brown marmorated stink bug, Halyomorpha halys, can be confused with other brown stink bugs. To identify this species accurately, examine its antennae for alternating bands of light and dark on the last two segments. Adults are a blotchy brown color, with alternating light and dark markings along the edges of the abdomen. They grow to 17mm in length. In its U.S. range, Halyomorpha halys adults may be observed from spring to September. In the fall, they may invade houses and other structures. Find stink bugs in your home in the fall, and there's a good chance you've got brown marmorated stink bugs.
First and second instars appear tick-like, but yellowish or reddish in color. The final three instars (five total) become darker and closer in appearance to the adults. Older nymphs have banded legs and antennae and abdominal markings like adults. Clusters of light green eggs may be found from June to August.
If you do find a brown marmorated stink bug, keep the insect in a vial or jar and report the find to your local extension office. This insect has the potential to become a serious agricultural pest, and scientists are tracking its spread.
Brown marmorated stink bugs feed on plants by piercing fruits and stems. The long list of host plants favored by this insect makes it a significant agricultural pest if populations get too large. Host plants include a variety of fruit and shade trees, as well as other woody ornamentals and even legumes. Known food sources include: pear, peach, apricot, cherry, mulberry, persimmon, and apple trees; Buddleia, honeysuckle, Rosa rugosa, and abelia shrubs; raspberries and grapes; and legumes including soybeans and beans.
The brown marmorated stink bug undergoes incomplete metamorphosis. In the U.S., only a single life cycle occurs per year. However, in its native Asia, five life cycles per year have been observed. As H. halys spreads south, more life cycles per year are likely.
Eggs - The female lays barrel-shaped eggs in masses of 25-30, on the undersides of leaves.
Nymphs - Nymphs emerge 4-5 days after eggs are laid. Each instar lasts about one week.
Adults - Adults fly, and become sexually mature about two weeks after their final molt. The female lays eggs at one week intervals. She can lay as many as 400 eggs in a season.
Special Adaptations and Defenses:
Like other cousins in the Pentatomidae family, brown marmorated stink bugs possess glands in the thorax capable of producing malodorous compounds. When handled or crushed, stink bugs release this foul smelling secretion. Their coloration provides camouflage from predators, such as birds.
Fruit tree orchards, soybean fields, and other areas where host plants occur, including the home landscape.
The brown marmorated stink bug is native to eastern Asia, existing in China, Japan, and Korea. In the United States, Halyomorpha halys has been recorded in Oregon, California, Pennsylvania, Maryland, New Jersey, and Delaware since 2001.
Other Common Names:
Yellow-brown stink bug, East Asian stink bug