Brown Marmorated Stink Bug (BMSB)
The brown marmorated stink bug has apparently been accidentally introduced into eastern Pennsylvania. It was first collected in September of 1998 in Allentown, but probably arrived several years earlier. They are now found in Manhattan, the Bronx, Queens, Brooklyn, and Nassau County.
This true bug is known as an agricultural pest in its native range of China, Japan, Korea and Taiwan. It becomes a nuisance pest both indoors and out when it is attracted to the outside of houses on warm fall days in search of protected, overwintering sites. It occasionally reappears during warmer sunny periods throughout the winter, and again as it emerges in the spring.
Adults are approximately 17 mm long (25 mm = one inch) and are shades of brown on both the upper and lower body surfaces (Fig. 1). They are the typical ?shield? shape of other stink bugs, almost as wide as they are long. To distinguish them from other stink bugs, look for lighter bands on the antennae and darker bands on the membranous, overlapping part at the rear of the front pair of wings. They have patches of coppery or bluish-metallic colored puntures (small rounded depressions) on the head and pronotum. The name ?stink bug? refers to the scent glands located on the dorsal surface of the abdomen and the underside of the thorax.
The eggs are elliptical (1.6 x 1.3 mm), light yellow to yellow-red with minute spines forming fine lines. They are attached, side-by-side, to the underside of leaves in masses of 20 to 30 eggs.
There are five nymphal instars (immature stages). They range in size from the first instar at 2.4 mm to the fifth instar that is 12 mm in length. The eyes are a deep red. Protuberances are found before each of the abdominal scent glands on the dorsal surface. The legs, head and thorax are black.
Figure 1. Adult brown marmorated stink bug.
This species probably has a single generation per year. However, in parts of sub-tropical China, records indicate from four to possibly six generations per year. Adults emerge from overwintering during the beginning of June or as early as March. They mate and lay eggs from June through August. The eggs hatch into small black and red nymphs that go through five molts during July and August. Adults begin to appear in mid August. The BMSB search of overwintering sites started in mid September and peaked during the first half of October.
We now know this species is an agricultural pest. In its native range, it feeds on a wide variety of host plants. Fruits attacked include apples, peaches, figs, mulberries, citrus fruits and persimmons. This true bug has also been reported on many ornamental plants, weeds, and soybeans. Feeding on tree fruits such as apple results in a characteristic distortion referred to as ?cat facing,? that renders the fruit unmarketable.
Even though these insects do not harm humans and do not reproduce inside structures such as houses, they cause concern when they become active and conspicuous in fall and spring. If many of them are squashed or pulled into a vacuum cleaner, their smell can be quite apparent.
Stink Bug Exterminating and Management
Before Bugs Enter a Building:
Mechanical exclusion is the best method to keep stink bugs from entering homes and buildings. Cracks around windows, doors, siding, utility pipes, behind chimneys, and underneath the wood fascia and other openings should be sealed with good quality silicone or silicone-latex caulk. Damaged screens on doors and windows should be repaired or replaced.
Exterior applications of insecticides may offer some relief from infestations where the task of completely sealing the exterior is difficult or impossible. Applications should be applied by a licensed pest control operator in the fall just prior to bug congregation.
After Stink Bugs Have Entered the Structure:
If numerous bugs are entering the living areas of the home you should attempt to locate the openings where the insects gain access. Typically, stink bugs will emerge from cracks under or behind baseboards, around window and door trim, and around exhaust fans or lights in ceilings. Seal these openings with caulk or other suitable materials to prevent the insects from crawling out. Both live and dead stink bugs can be removed from interior areas with the aid of a vacuum cleaner.
It is not advisable to use an insecticide inside after the insects have gained access to the wall voids or attic areas. Although insecticidal dust treatments to these voids may kill hundreds of bugs, there is the possibility that carpet beetles will feed on the dead stink bugs and subsequently attack woolens, stored dry goods or other natural products in the home. For this reason use of these materials is not considered a good solution to long-term management of the problem.