A New Invasive Bug Attracts Attention

Back in the 70s and 80s the government decided that we needed to benefit the country by importing products from other countries. After all, we were the superpower, the great economic engine and our citizens liked buying stuff, especially cheap stuff. Big box stores flourished, providing lots of goodies from China, Vietnam, Korea and Japan that dazzled the eyes and did not cost much. Everything was wonderful because our consuming society had tons of stuff to put in its large houses and cars.

Now the party has ended and we find out that we got a bonus prize: all sorts of new, interesting bugs that came along for the ride. It is little like having a hangover after a great party. We have a huge deficit and lots of new bugs and not necessarily friendly bugs. It is hard to make money when you have bugs on your flowers.

The brown marmorated stink bug (BMSB), Halyomorpha halys (Stål) was introduced from Asia into the Mid-Atlantic region. This infestation is believed to have originated in Allentown, Pennsylvania in the mid 1990s. Since then, BMSB has spread to New Jersey, Maryland, Delaware, West Virginia, and Virginia, mainly via car trunks and campers. The brown marmorated stink bug has also been detected in Mississippi, Florida, Ohio, Oregon, and California.

BMSB is a polyphagous pest whose host range includes high-value crops such as cut flowers, vegetables, tree fruits, ornamentals, hardwood trees and cultivated crops such as soybean and sweet corn. In the region encompassing western Maryland and the eastern panhandle of West Virginia, populations have steadily increased annually since first detection in 2003 and 2004, respectively. During the 2009 and 2010 growing season, serious economic injury to peach, apple, and Asian pear due to large BMSB populations was commonly detected in orchards July through October.

I have had three green-house operations bring in potted chrysanthemums with brown marmorated stink bug feeding on mum stems. In nurseries we found them feeding on crabapples, cultivated apples, hibiscus, and holly berries. In landscape we have reports of them feeding on basil, tomatoes and peppers, and in cut flower operations on sunflowers and zinnias. They appear to be very attracted to sunflower florets.

Some commercial growers have used increasing numbers of pyrethroid applications, a class of insecticides found to be effective against BMSB. The trouble is that the insects attack fruit and vegetables just about harvest time. This means a very short time before the consumer will be handling the treated product.

In addition to the agricultural threat posed by BMSB, this invasive species is also emerging as a serious nuisance pest for homeowners and business. In the fall, BMSB adults move from host plants and seek overwintering sites, particularly in homes and other buildings. During this behavioral shift, profound numbers of adults will move toward and aggregate on the outside of structures and eventually seek entry within. Local newspapers and television stations in mid-Atlantic states have reported on this summer/fall aggregation behavior, high-lighting the problems for homeowners. After entry into overwintering sites, BMSB will often be found aggregating in large numbers in small confined spaces such as behind bookshelves, beneath mattresses, inside filters of window-mounted AC units within homes or between layers of stacked building materials in garages. This highlights the societal impact imposed by this pest and the need to address homeowner and grower concerns. This is a new pest for all of entomology and there is much to learn before we can provide really good control techniques.

We know that they are attracted to artificial lights at night and cluster near sodium vapor lights high in the red spectrum. I am working with Maryland growers to set up trials with traps that use black and white emitting lights with different hues to see if we can develop an effective trap. We have just started this project in early September so we don’t have anything to report yet.

Meanwhile, pyrethroids do kill them but many beneficial organisms as well. We must continue the research efforts and find a control that has less impact on the environment.

Stanton Gill

Extension Specialist

Stanton Gill is an extension specialist (professor-ranked principal agent) in IPM and entomology with the University of Maryland Extension, based at the Central Maryland Research and Education Center in Ellicott City. He is also a professor in the Landscape Technology Program at the Germantown Campus of Montgomery College. Contact him at [email protected]