As temperatures begin to rise in spring, the brown marmorated stink bugs (BMSBs) that invaded homes in the fall begin emerging from their winter hiding places, looking for food and mates. While a nuisance indoors, these flat, shield-shaped bugs are a real threat to home gardens and agricultural crops throughout the growing season. “It’s a mobile pest—it moves easily from plant to plant—and there are a lot of host plants,” says Anne Nielsen, Ph.D., fruit entomology extension specialist at Rutgers University in New Brunswick, New Jersey.
“They aren’t picky eaters,” says Tracy Leskey, Ph.D., research entomologist with the USDA Agricultural Research Service’s Appalachian Fruit Research Station, in Kearneysville, West Virginia. Inadvertently imported from Asia in the 1990s, the notorious BMSBs feed on apples, peaches, corn, peppers, tomatoes, grapes, and raspberries, as well as soybeans and forage crops. “I understand how desperate folks are,” Leskey says. “BMSBs have ruined my tomatoes every year since 2009. We have had organic and conventional growers, as well as backyard gardeners, throw their hands up in the air with regard to this pest.”
Mild weather in the mid-Atlantic region compounded BMSB problems for growers and gardeners by allowing two generations of the pests to develop during the 2012 growing season. “Stink bugs do have natural predators, but they haven’t kept up with the size of the stink-bug populations,” Leskey adds. “There are many more stink bugs than predators.”
To protect garden crops from the damage BMSBs inflict with their piercing-and-sucking mouthparts, Nielsen recommends using a variety of methods, including row covers, trap crops, pheromone traps, and natural predators. Commercially available stink-bug traps “are good for monitoring, and you remove some bugs from the population,” Nielsen notes. She suggests growing early crops of stink-bug favorites such as sweet corn, amaranth, and okra as “sacrificial plants” that can be destroyed once they’re infested with the pests. “Although you want to plant the trap crop close to your vegetables, we don’t yet know what the ideal distance is,” she cautions.
Natural enemies of stink bugs include ants, ladybird beetles, and some lacewings, all of which prey on stink-bug egg masses. Plant sunflowers and French marigolds to attract these beneficials. Hand-pick the nymphs and adults into soapy water—wear gloves—and destroy clusters of light green, barrel-shaped eggs found on the undersides of leaves. Insecticidal soap sprays are most effective against younger stink bugs, Nielsen adds. Because BMSBs are unlikely to ingest a fatal dose of insecticide through feeding, sprays work best when they directly contact the pests. The pests’ mobility—BMSBs quickly repopulate treated areas—and the harm to beneficial insects make spraying even organic pesticides undesirable.
To use traps for both monitoring and controlling stink bugs, put them out by April 1, recommends Stephanie Cates, director of marketing for Sterling International, manufacturer of Rescue stink-bug traps. In early spring, place traps in trees and bushes where emerging bugs will head to mate, says Cates. Secure each trap so that both the top and the bottom are in contact with the plant, so the traps’ vanes serve as ladders for immature stink bugs to climb into the trap. Once in, the bugs are unable to escape, and they dry up and die.
Hang traps from stakes spaced every 20 to 30 feet around the perimeter of your garden to provide protection from flying adult stink bugs throughout the growing season, Cates suggests. “You won’t lure them to the garden,” she adds. “They’ll already be there if there’s something to eat.” The key is to start early, Cates says. “If you wait until you have thousands of stinkbugs on your home [in the fall], you’re not going to be able to wipe out such a large population. If you wait until they’re all over your plants, you have a big problem.”
To learn more about research underway to develop controls for brown marmorated stink bugs, visit stopbmsb.org.