The Latest Buzz on the Brown Marmorated Stink Bug
Posted: September 30, 2013
"Brown" describes the mottled brown color of this shield-shaped bug. "Marmorated" describes the coppery to bluish-metallic punctures noticeable on the surface of the head and body. "Stink" describes the pungent odor released from scent glands when the insect is disturbed, and "Bug" describes this true bug with its piercing-sucking mouthparts.
In the years since they were first accidentally introduced into the United States from Asia, and first detected in the Allentown, Pennsylvania, area in 1998, BMSB have been considered primarily a "nuisance" pest due to their overwintering habits inside buildings. And prior to 2010, their plant feeding damage was scattered - not considered significant enough to warrant much attention from researchers or governmental authorities. They were just a nuisance.
But that changed in 2010: BMSB caused major damage to agricultural crops, and they are still spreading. They have now been detected in 40 states and Ontario, creating severe agricultural and nuisance problems in the mid-Atlantic states and posing nuisance problems in at least 13 other states, including Washington, Oregon, and California. They've even been found in Hawaii.
In 2010, many orchard growers in southern Pennsylvania, northern Maryland, and West Virginia reported BMSB damage to their peaches, apples, and pears, to the tune of an estimated $37 million, and some suffered losses of up to 60%. In the years since, BMSB have continued to present a significant season-long challenge to farmers.
The USDA's Agricultural Research Service, working with universities such as Penn State, Virginia Tech, Rutgers, and the University of Maryland, has developed a BMSB action plan, with research directed towards determining basic biology and behavior characteristics, developing monitoring tools, and finding effective management methods for both agricultural and urban settings.
As a home gardener, what can you do in the fight against BMSB? One good place to begin is the Stop BMSB website. This website has current information about BMSB and links to websites about much of the research that is being conducted on BMSB, which will be helpful as scientists figure out ways to control these pests.
Scouting & Monitoring
Scout for and destroy eggs and nymphs. One female can lay more than 400 eggs before she dies; the elliptical eggs, laid in clusters of 25 to 35, range from light yellow to greenish white in color and can be found on the underside of leaves from May through August. The eggs hatch in about a week, and the stinkbug goes through five nymphal stages, called "instars," before the final molt into an adult. These juvenile stages do not look exactly like the adult, with a yellowish-red abdomen and black stripes early on, but all stages have similar antennae - black with white banding.
Researchers have found out that while BMSB have a very broad host plant range, there are certain plants that they prefer. When the insects first emerge from overwintering sites in the spring, they go to plants that expose them to sunlight. As they feed and breed during the summer months, they tend to favor plants with buds, flowers, fruits, and pods.
There is a list of 170 host plants available on the website; particular BMSB favorites are listed in bold print. Favorite ornamental and wild plants include tree of heaven, catalpa, eastern redbud, English holly, crabapple, paulownia, cherry, and sunflower; favorite food crops include pepper, soybean, peach, pear, eggplant, tomato, and corn.
Researchers have also determined where BMSB overwinter if they're not inside your house. They prefer large, dry, dead standing trees, especially oak and locust; the dead wood and peeling bark of these trees give the BMSB a place to crawl into and hide. Better understanding of the basic life cycle of this pest will help scientists determine the most effective long-term control methods.
Physical & Mechanical Controls
Pheromone lures have been developed, but more for monitoring purposes than control. Plans for light traps using soda bottles can be found on the Internet, but a researcher at the University of Maryland did not find them to be very effective. Another style of trap, consisting of cardboard separated by narrow wood slats, has been effective for the New Jersey homeowner who invented it, since BMSB like surfaces touching both their upper and lower sides when they overwinter.
Indoors, vacuuming or sweeping up BMSB is one way to get rid of them, but don't leave them in the vacuum bag, as it soon may begin to stink. Drowning the bugs in soapy water as you find them will work for a small infestation. Outdoors during the growing season, row covers over home vegetable garden plants have been suggested as a way to keep BMSB off some crops.
For commercial fruit growers in the mid-Atlantic states, an emergency exemption was granted by the EPA to use the insecticide dinotefuran on orchards, although this insecticide may also kill beneficial insects. Unfortunately, for homeowners, no thoroughly effective insecticide is yet available, and there is concern about the stinkbugs developing resistance to commonly used insecticides. Lab studies have shown that some insecticides did not kill BMSB; the treatment only put them into a coma-like condition for a week or so, and then they came "back to life," after their bodies had broken down the insecticides.
Azidirachtin, insecticidal soap, pyrethrins, and synthetic pyrethroids are some chemicals that may kill or repel stinkbugs outdoors in the garden. Kaolin clay (Surround) sprayed on fruit may reduce BMSB feeding damage. If you choose to use an insecticide, be sure that the pest and plant are listed on the label, and read and follow the label directions. For BMSB, target nymphs rather than adults; and apply after the eggs have hatched and when nymphs are present on the plant. Use of insecticides inside the home to control stinkbugs is not recommended.
Spiders, starlings, chickens, praying mantids, and assassin bugs have been reported to eat BMSB. Unfortunately, these individual predators can't make a significant dent in BMSB infestations. The USDA is currently evaluating a group of tiny parasitic wasps, Trissolcus , found in China that lay their eggs in BMSB eggs. If they prove effective and safe to release, they might be available sometime after 2013. Researchers have also found some naturally-occurring fungi that attack BMSB.
Prepare for this Fall
Now is the time to start caulking and sealing exterior cracks and crevices around your home, and to replace damaged door and window screens, to prevent BMSB from once again using your home as overwintering quarters. This is, for now, still the best advice that the experts can give to homeowners battling BMSB.
- Consumer Horticulture Extension Educator