2010-09-23 / Front Page

House invaders return to winter residences

Increasing number of stink bugs reported throughout New Jersey
The pesky brown marmorated stink bugs (BMSB) that exited houses in the spring to seek food and mate during the summer are now invading homes to return to their warm winter residences. But this fall, the invaders that are scientifically known as Halyomorpha halys are returning in record numbers.

“There has been an explosion in the population of BMSB this year in both urban and agricultural areas,” said George C. Hamilton, an extension specialist in pest management at Rutgers University, New Brunswick, who has extensively studied the BMSB. “The reason is not sure, but it may be due to an increase in the temperature this summer.”

Hamilton, who is a professor and the chair of the Department of Entomology at Rutgers, said exceptionally warm weather can sometimes produce two generations of an insect species, such as the BMSB. This year in West Virginia that did happen with the BMSB.

According to Hamilton, the BMSB were first collected in the United States in Allentown, Pa., in 1996. It is believed they may have accidentally entered the country via shipping containers from Asia. Three years later, the bugs (they are true bugs of the order Hemiptera) were found in Milford, N.J.

Since 2002, the BMSB have inhabited the northern and central parts of New Jersey, and by 2005 had spread to the southern part of the state. Currently, the BMSB are found in the Mid-Atlantic states and in all New Jersey counties, he said.

“The BMSB that are now entering houses are an invasion of adult insects, not an infestation,” said Hamilton. “These adults are not nesting or laying eggs. BMSB only breed outside the house or structure.”

He explained that the BMSB can fly, but are not poisonous and will not bite or sting humans or pets. If the BMSB are stressed or crushed, they will emit a pungent odor. While the bugs are a nuisance for homeowners, they have not been known to cause any structural damage.

“The real damage from the BMSB is agricultural,” said Hamilton. “They damage crops such as apples, pears and peaches in states including West Virginia, Pennsylvania, Maryland and New Jersey.”

This year in New Jersey, he said, the BMSB have been reported damaging peppers and tomatoes, too. The characteristic damage is usually a small, necrotic scarred area that some people say resembles a “cat face” that renders the fruit or vegetable not suitable for market.

“Research is ongoing for answers to manage the problem of the BMSB that will thrive as long as they have food and proper habitat,” said Hamilton, who collected specimens to confirm sightings and to determine how the DNA of the BMSB is changing as it spreads across the United States. “Right now we have mechanical and chemical pest management techniques.”

Caulking windows and doors, fixing win- dow screens, checking screens on attic vents and soffit vents and removing window and wall air conditioners are mechanical ways to limit winter hiding places. Other suggestions include vacuuming the bugs and disposing of them outside, or coaxing individual bugs onto a newspaper and releasing them outside. Do not swat the bugs or they may spray, he cautioned.

For chemical methods, Hamilton said spraying with pyrethroid or neonicotinoid insecticides on the exterior of a house, foliage or structures as a perimeter spray may be effective. He does not suggest or recommend using these insecticides inside the house.

Since about 2008, Hamilton and Rutgers University have participated in collaborative research of BMSB with entomologist Richard Cooper of Cooper Pest Solutions, based in Lawrenceville.

“Prior expectations were low, but we are learning more and refining our techniques of insecticide usage with the key being the timing of the application of the insecticide for treating BMSB,” said Cooper, who is pursing a doctoral degree in entomology at Rutgers unrelated to BMSB research.

He said if the BMSB are treated before mid-September, the activity can be reduced by 90 to 100 percent rather than waiting until the bugs are fully active in a home. From Sept. 15 to Oct. 1 there is a decease in effectiveness, but there are still pretty good results, and treating after Oct. 1 lowers the results further.

“We have treated a lot of properties this year and next year we will learn more,” said Cooper, who is the technical director of the family-owned business. “The process is to target exterior areas and only specific non-living areas, such as attics, with low volumes of insecticide. Timing of applications and preventing entry help to significantly reduce BMSB activity.”

Cooper said this year’s invasion of the BMSB in homes and commercial buildings is staggering and has provided some new insights.

“We are finding that BMSB are entering structures earlier in the fall and staying later in the spring before exiting,” he said. “No structural damage has been observed.”

Andrew Cedar, head technician for Edison Heating and Cooling, South Plainfield, said he has found the BMSB in commercial and home air conditioning units.

“I have been in the business for 20 years, and this year I have seen more stink bugs than ever,” said Cedar, who is a Manalapan resident. “They are destroying the vent motors of the AC units. I want people to be aware that homeowners and businesses need to protect their units by using covers or screens to extend the life of their system.”

The U.S. Congress is also aware of the problems of the BMSB. On Sept. 14 a U.S. House of Representatives briefing sponsored by Congressman Roscoe Bartlett (R-Maryland) was held to discuss the problems that various states are having with the BMSB. The Washington, D.C., staff of Rep. Chris Smith (R-N.J.) confirmed the briefing and noted that New Jersey was represented by the expert testimony submitted by Dr. Hamilton of Rutgers.

Information from the Rutgers website www.njaes.rutgers.edu/stinkbug lists the BMSB as a non-native U.S. species usually found in Japan, China and Korea. It is a plantfeeding insect that uses a proboscis (tube-like structure) to pierce a host plant and suck its nutrients, preferably from fruit trees and ornamental plants that bear berries or fruit.

The shield-shaped body of the adult BMSB is approximately 17 mm (5/8 of an inch) and is generally light brown with alternating black and white sections (marmorated or marblelike) on the antennae and at the rear of the wings. When the insect is disturbed, stressed or crushed, a pungent odor is released from its scent glands located on the abdomen and thorax: hence the name “stink bug.”

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