Brown Marmorated Stink Bug — Invasive Pest
The Brown Marmorated Stink Bug, Halyomorpha halys, is an invasive stink bug that has emerged as
a major pest of tree fruits and vegetables causing millions of dollars’ damage to plants.
The eggs of the Brown Marmorated Stink Bug are a light green or light blue color, about .03 inches in diameter,
and are laid in clutches of approximately 28 eggs. Eggs are usually located on the underside of leaves of host
plants. As the embryo develops it may become visible through the egg, with the eyes appearing as two red spots.
The first instar nymphs are approximately 0.1 inch in length, with a black head and thorax and an orange-red
abdomen. Following the transition to second instar, the nymphs lose a majority of their orange-red coloring.
Second instar nymphs appear dark, with rough spiny projections along the lateral edge of the thorax. Wing
buds begin to develop with each successive molt. Later instars have a black to gray base coloration with
noticeable spines along the humeral margins, as well as white bands on the legs and antennae.
Adults of the Brown Marmorated Stink Bug are larger than those of most native stink bug species, ranging from 0.5 to 0.7 inches in
length. The base color is a mixture of brown, dark red and black on the dorsal surface, with a beige or
cream-colored ventral surface punctuated with metallic green markings on the ventral thorax. Key features
for identification of the adult include white bands on antennae and legs, no shoulder spines, and alternating
dark and light bands on the margin of the abdomen.
The Brown Marmorated Stink Bug has the potential to cause damage to several crops, including tree fruit,
nuts, vegetables and row crops. During outbreak years the Brown Marmorated Stink Bug has caused
significant losses to tree fruit producers, damaging apples, peaches and pears. In 2010 the Brown
Marmorated Stink Bug outbreak was the cause of over $37 million USD in losses to tree fruit producers
in the mid-Atlantic region.
Vegetable producers have experienced economic damage, with feeding reported on sweet corn, beans
and tomatoes. Row crops such as field corn and soybean have also been affected
by the Brown Marmorated Stink Bug, with damage occurring near field margins adjacent to wooded
areas that serve as habitat for Brown Marmorated Stink Bug populations.
Feeding on tree fruit, nuts and some vegetables can lead to corky spots in the flesh directly below
the feeding site. Feeding can also cause discoloration, necrosis or chlorotic spots due to tissue
damage. Feeding on developing fruit, particularly peaches, can cause cat facing damage, in which
the growing fruit fails to expand at the site of feeding injury, resulting in a malformed fruit. In most
cases feeding by nymph and adult stages renders the fruit unmarketable.
Management of the Brown Marmorated Stink Bug in agricultural settings has primarily relied on the
use of broad-spectrum insecticides. Because the pesticides that are most effective are often toxic
to natural enemies, pollinators and other beneficial insects, strategies to reduce the amount of
pesticides used for control have been developed. Among these is the use of border sprays, which
take advantage of the increased pest densities observed on border rows of crops, especially when
borders are adjacent to forested areas.
In residential settings the primary means of reducing home invasion by the Brown Marmorated Stink
Bug is to seal entrances to the home, including repairing insect screening and sealing cracks and
other building openings. Various traps have been designed for home use, with varying levels of
success. Squashing and killing the bugs is not a solution. It will release the most potent smell that
will linger for days on your shoes and the surface you crushed them on.
Native natural enemies have not been effective at controlling populations of the Brown Marmorated
Stink Bug in its invasive range. Predators have been observed feeding on the Brown Marmorated
Stink Bug, however, low rates of control have been reported, generally below 20%. However, the Brown
Marmorated Stink Bug experiences upwards of 70% parasitism from a number of bees, wasp and
ant egg parasitoids.
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