University of Maryland Extension

Brown Marmorated Stink Bug Update

Author: 
Stanton Gill, University of Maryland Extension Specialist, Nursery and Greenhouse Management

 

In 2010 and 2011, brown marmorated stink bugs (BMSB) were seen in extremely high numbers in the Mid-Atlantic region. They were responsible for causing major economic damage to fruit and vegetable crops at a number of orchards and farms. In addition to causing damage to plants and fruit, brown marmorated stink bugs are a major nuisance to people. Adult stink bugs often seek shelter inside houses and other buildings. Once inside, they congregate almost anywhere. These pests will not cause structural damage or reproduce in homes. They do not bite people or pets. Although they are not known to transmit disease or cause physical harm, the insect produces a pungent, malodorous chemical and when handling the bug the odor is transferred readily.

The good news is that the brown marmorated stink bug populations have been significantly lower in 2012. In the late summer of 2011, weather conditions were unfavorable for the BMSB. Heavy rainfall in early September from tropical storms appears to have reduced the population of nymphs in the fall with fewer overwintering adults present in 2011 in the majority of residences in Maryland. The winter of 2011 to 2012 was very mild with warm periods interspersed with cold periods. The overwintering adult stink bugs came out of their overwintering sites during the warm periods using up valuable body food reserves causing a fair amount of mortality in overwintering populations. In the spring of 2012 there were greatly reduced populations of adult BMSB found in home gardens and in fruit plantings. We had reports of nymphs and adults feeding on home planting of blackberries, raspberries and vegetables during the summer of 2012, but in most cases, the populations were not at highly damaging levels. As we move into September of 2012 there are reports of increased activity of adults and nymphs in home gardens. People who turn on outdoor light systems are reporting clustering of adults in the area under the lights. These stink bugs are highly attracted to artificial lights in September.

When the weather turns cool at night, adult brown marmorated stink bugs look for overwintering sites and can be found on the outsides of buildings or inside near doors, windowsills, and other entry points. They can also be found in leaf litter and vegetation outdoors.

Parasites of BMSB
A study conducted in 2005 found less than 5% of BMSB eggs were parasitized. In a preliminary study by the University of Maryland, researchers are reporting an increasing number of BMSB eggs being parasitized by native parasites (12 to 29%). It is very good news that native parasites are adapting to this new food source.
    
Several nursery and landscape managers report that native bird species have been observed feeding on BMSB. Chickens and Guinea fowl will feed heavily on nymphs and adults. In some counties, residents are allowed to have a limited number of hens but not a rooster. Check with your local county zoning board to see what the situation is in your county.

Control Options

Physical Control:
Adult brown marmorated stink bugs can enter homes through cracks and crevices. A few simple tips to help keep them from entering homes are:

  • Caulk windows inside and out.
  • Weather strip entry doors and/or install door sweeps if daylight is visible around the perimeter of the door.
  • Rake away all debris and edible vegetation from your home’s foundation to keep from attracting pests.
  • Inspect for and seal foundation cracks to block a potential point of entry.
  • Secure crawl space entries.
  • When insulating exposed plumbing pipes around the foundation or the crawl space of your home, caulk small gaps and fill larger ones with steel wool.
  • If your home has a fireplace, cap or screen the top of the chimney to keep out pests.
  • Both live and dead brown marmorated stink bugs can be removed from interior areas with the aid of a vacuum cleaner, but the vacuum may smell of stink bugs for a period of time.

Trapping:
Blue or black fluorescent lights attract the brown marmorated stink bug. There are several light traps that use these color spectrums that are available of the market. They will trap adult BMSB but the significance of the reduction in population is still being evaluated.

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