The invaders are scary looking, but they smell worse than they look. And the last thing you want to do is stress them or crush them.
Though harmless to humans and pets, the invaders are the brown marmorated stink bug (BMSB), Halyomorpha halys (Stahl). They are becoming an increasing nuisance for homeowners and possibly will be an agricultural pest in New Jersey, experts at Rutgers University say.
Homeowners are finding BMSB adults that have overwintered in their houses, and now these insects are crawling and flying to seek an exit outside to feed and mate during the spring and summer months.
Before they get out, however, the far-fromattractive pests often give homeowners a good scare, when they find them on their pillows or buzzing around a lamp.
According to information from the Rutgerswebsitewww. njaes.rutgers.edu/stinkbug, the BMSB, a non-native species found in Japan, China and Korea, is a plant-feeding insect that uses a proboscis (tube-like structure) to pierce a host plant and suck its nutrients. Its favorite food includes fruit trees and many ornamentals.
The shield-shaped body of the adult BMSB is approximately 17mm (about a halfinch) and is generally light brown with alternating black and white sections (marmorated or marble-like) on the antennae and at the rear of the wings. The scent glands are on the abdomen and thorax. When the insect is disturbed or crushed, a pungent odor is released; thus the name stink bug. Whilemany insects are called bugs, the BMSB is a true bug (Order: Hemiptera). It goes from a cluster of 20 to 30 tiny light green eggs found on the underside of leaves through five nymphal (instar) stages to the adult. The BMSB breeds only outside the house or structure.
George C. Hamilton, Ph.D., an extension specialist in pest management at Rutgers University in New Brunswick, has extensively studied the BMSB and is collecting specimens to confirm sightings and to determine how the DNA of the BMSB is changing as it spreads through the U.S.
“The BMSB are currently found in all the counties of New Jersey,” said Hamilton, a professor and the chair of the department of entomology at Rutgers. “They probably came here from Asia via shipping containers. Since they are good flyers and can hitchhike on vehicles, they have spread to numerous states.”
In 1996, the BMSB was first collected in the United States in Allentown, Pa. Three years later, it was found in Milford, N.J. In 2002, it inhabited the northern and central parts of New Jersey, and by 2005 it spread to the southern part of the state.
Since 2000, populations of the BMSB have been confirmed in Mid-Atlantic states as well as many others such as Oregon, Ohio and California.
“In West Virginia, the apple growers are experiencing economic damage from the BMSB,” Hamilton said. “Usually, the characteristic damage is a small, necrotic area that renders the fruit not suitable for market.”
Hamilton said the BMSB, which has a six- to eight-month lifespan, has few natural predators here. “Some tachinid flies and egg parasitoid wasps are known to feed on the BMSB, but they are not their favorite food,” he said.
Hamilton is doing an ongoing DNA study on the BMSB and hopes to learn its exact country of origin into the United States and more. Meanwhile, he offers some mechanical and chemical suggestions to rid a house of BMSB.
Mechanically, he suggests using a vacuum and disposing of the bugs outside. Or individual BMSBs may be coaxed onto a newspaper and can be released outside. Do not swat them or they may spray, he cautions.
“The BMSB will not bite or sting humans and is not poisonous,” said Hamilton. “The best thing to do is to prevent their entry in the house during mid-September and October.”
Caulking windows and doors, fixing windows screens, checking screens on attic and soffit vents and removing window air-conditioners are ways to limit a winter hiding place, he said.
To chemically control the BMSB, Hamilton said spraying with pyrethroid or neonicotinoid insecticides on the exterior of a house as a perimeter spray may decrease BMSB numbers if applied when the insects first appear. He does not suggest or recommend using these insecticides inside the house.
Jeff Klayman, owner of Freehold Pest Control, said that about two or three years ago his company began receiving calls about the BMSB and now they are increasing.
“I’ve treated hundreds of infestations for the BMSB in houses and businesses,” said Klayman, a licensed certified pesticide applicator with 25 years of experience in the Freehold area. “Every few years, nature gives us a new problem. Before it was the Asian ladybug and the boxelder beetle, and now it’s the BMSB.”
Klayman said that after receiving a call about the BMSB, an assessment of the infestation is done and a safe treatment with an insecticide is recommended.
“It’s very hard to seal a home against an invasion of so small an insect,” he said. “We are cautious when we treat with an insecticide.”