There’s a new pest in the US, and it’s causing a lot of worry. Introduced just over a decade ago from its native Asia, the brown marmorated stinkbug is an insect that’s proven difficult to contend with. But it’s not that unpleasant smell they release that makes these bugs problematic. They are tough, very invasive, and they have quite an appetite for our crops.
The brown marmorated stinkbug is a dime-sized insect featuring a flattened, mottled brown body, long antennae, red eyes, and a hard, shield-shaped outer shell. It releases an unpleasant odor when squashed or when feeling threatened.
The brown marmorated stinkbug feeds on the fruits and leaves of many different plants and has a particular taste for many popular fruits and vegetables, including all stone fruits, apples, grapes, tomatoes, peppers, lima beans, and corn.
Female stinkbugs lay little clusters of light green eggs on the underside of leaves every summer. Mottled yellow, black, and red nymphs hatch soon after and quickly grow through another four nymph stages before becoming fully formed adults. Depending on the climate, stinkbugs can produce between one and five generations every year.
The stinkbug is a large, diverse genus that includes some indigenous North American stinkbugs, which pose no threat to crops. The brown marmorated stinkbug, however, hails from a completely different continent, with different insect predator species. What this bug found when it arrived in North America was a paradise of food to eat, warm homes to hibernate in, and no natural predators to keep their numbers in check. Birds won’t eat it, and predatory insects don’t seem to recognize it as food.
Reports of the brown marmorated stinkbug first appeared in Allentown, Pennsylvania in the late 1990s. Since then, in the span of just over a decade, the bug has spread to 38 states nationwide, appearing by the hundreds of thousands in Florida, California, the Northwest, and almost everywhere in between. Besides being a household pest, the brown marmorated stinkbug is an invasive species that poses a serious economic threat to the agriculture industry. In 2010 alone, this insect caused an estimated $37 million in damages to the apple industry.
Controlling Stink Bugs in the Garden
With invasive numbers continuing to go unchecked, and with a taste for our favorite foods, it’s no wonder that the stinkbug is becoming such a worry for commercial farmers and home gardeners alike. Not only do stink bugs render fruit inedible and unmarketable, they also make foliage unsightly and leave plants stressed and open to infection from the tiny bite wounds left from feeding. During especially bad years, managing this pest isn’t easy, but it is possible.
When tending your crops, especially any fruit trees, tomatoes, peppers, and grapes, keep an eye out for stingbug damage. Damaged fruits display scarring, pitting, and a mealy texture. Damaged leaves also show scarring in the pattern of round stippled areas.
Because the brown marmorated stinkbug is so new, few pesticides (natural or otherwise) have been tested for effectively controlling them, though any that are marketed for native stinkbugs seem to work just fine. There are, however, other more effective and long-term methods of control in the works:
- Traps: Researchers tasked with finding effective methods of control have brought back traps used on these insects in their native Asia
- Natural controls: Researchers have also begun to introduce a parasitoid wasp species native to Asia and natural enemy of the brown marmorated stinkbug. Purposefully introducing a new species to the US takes time and a lot of paperwork from the USDA, EPA, and others, as this new wasp could threaten native stinkbug species. Preliminary tests show great promise though.
Controlling Stink Bugs in the Home
Brown marmorated stinkbugs aren’t just a pest outside; they infest the indoors as well! As cool weather starts to show up in the fall, these stinkbugs begin looking for a warm, safe place to hibernate. Out in the wilderness, many hide out under fallen logs or under a pile of leaves, but most, if given the opportunity, choose to winter inside houses, sheds, and other structures. You may notice only one or two inside your home or outside by windows and doors, but in some cases, these bugs can invade by the hundreds.
Once a stink bug makes it indoors, it can post up just about anywhere, including behind bookshelves, in windowsills, under baseboards, and any other place that’s dark and sheltered. The good news is that these pests, unlike termites and other insects, do not cause any damage to your home at all, won’t reproduce inside, and don’t bite, so they aren’t a threat to children or pets. Their stench that gives them their name though and the potential to cause allergies in some individuals, certainly make them unwanted guests.
Prevention is the best method of control here. Like spiders and insects, stinkbugs enter the home through small cracks, especially around windows and doors. Take the time to properly seal your home for the cold winter ahead, and you’ll also be sealing your home against these invaders. Some simple prevention steps you can take:
- Caulk all windows
- Weather strip all doors
- Seal any cracks in the foundation or elsewhere that may give bugs access to the indoors
- Screen your house’s chimney, if it has one
- Clear piles of leaves and other debris near the house
- Cut back or remove vegetation harboring stink bugs
While common home sprays labeled for indigenous stink bugs work, they are not an effective long-term solution. Many homeowners instead are vacuuming up the bugs as they find them (which will stink up the vacuum, by the way). More severe cases may require contacting a local pest control expert with experience in managing brown marmorated stinkbugs.
Not sure if brown marmorated stinkbugs have invaded your region? Contact your local Cooperative Extension Office for more info, as well as additional advice on control measures. If these stinkbugs have not yet been reported in your area and you suspect you have them, try your best to catch one and report it immediately to your local Cooperative Extension Office.