Stink bugs literally stink and are also tough to eliminate from your house and garden. We talked to the experts for solutions.
If you spend any time near farms, vegetable gardens or fruit trees, you’ve probably laid eyes on a brown marmorated stink bug. Some people refer to this insect as a shield bug, but either moniker identifies the same pest. (The scientific name for the stink bugs is Halyomorpha halys).
More concerning than their name, though, is their game. These not-so-innocent looking insects have one goal in life — to devour just about any crop they can get their tiny little legs on. This includes everything from tomato plants to peppers and green beans.
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What Are Stink Bugs and Where Did They Come From?
Shield/stink bugs are an invasive species that arrived in the U.S. in the 1990s from Asia via Allentown, Pennsylvania, says David Price, a certified entomologist and technical director for Mosquito Joe, a nationwide pest control company. According to the Environmental Protection Agency (EPA), the insects likely hitched a ride in a shipping container. From there, the pests spread rapidly around the nation.
Now, shield bugs are almost everywhere — in 47 states to be exact. They are the biggest nuisance in Oregon, Michigan, Tennessee and the mid-Atlantic states, where they are often found chowing down on agricultural crops. Favorite food sources include apples, pears, grapes, peppers, tomatoes, hazelnuts and corn.
“They actually attack agricultural crops pretty aggressively,” David says. How aggressively? In 2010, tree fruit producers lost more $37 million in crops to stink bugs, per a report from the University of Florida.
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What Does a Brown Marmorated Stink Bug Look Like?
Shield/stink bugs are brown, with white bands on their antennas and legs. They also have alternating light and dark bands on their abdomen. As for the exoskeleton, it resembles — you guessed it — a shield.
If you see a green bug with a similar shape, yes, that is a shield bug, too. However, the green version is native to North America and therefore not as much of a nuisance to crops, says Heather Stoven, an entomologist with Oregon State University. They still stink, though.
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Why Are Shield Bugs Also Called Stink Bugs?
And speaking of the stink, what is the story behind their nickname?
“When you crush them, they have a really foul odor,” says David. The odor, he says, exists to fend off would-be predators. It works, too; the bug has no known predators. The odor is not harmful, David says, just unpleasant.
Signs of a Stink Bug Problem
Like many insects, stink bugs lay their eggs on the underside of leaves. Once the eggs hatch, the nymphs (i.e. young insects) start feeding on those leaves, eventually joining their adult relatives on the fruits and vegetables themselves. You’ll know they’ve been around because you’ll see unsightly brown spots on the skins of your crops.
Unfortunately, they don’t disappear in winter, either. Instead, David says, they seek shelter and warmth in and around your home.
Potential stink bug hibernation sites include overgrowth and weeds around the yard, wood piles, or any little crack or hole on a house or shed they can squeeze into. They’ll hang out there all winter long. When spring arrives, they’ll move out of hiding and seek out your garden.
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Get Rid of Stink Bugs Without Using Pesticides
We wish we had better news, but it isn’t easy to keep brown marmorated stink bugs away from your garden plants. They are extremely prolific with no known predators (though its cousin, the green stink bug, has many predators). David says pesticides have little effect on them thanks to their tough-as-nails exoskeleton.
The best you can do is to control them, and consider yourself lucky if sightings in your garden are few and far between. Here are a few tips to keep them at bay, per David and Heather:
- Make sure all the cracks around your doors, windows, siding and pipes are well-sealed before winter. And don’t leave piles of yard debris sitting around. This will discourage overwintering.
- If you see them crawling around your house after a long winter’s nap, vacuum them up and dispose of them.
- When spring arrives, hang pheromone traps around your garden so you can catch them in the act.
- Check leaves for eggs. If you see them, remove or cut the leaves off.
- Spray plants with a kaolin clay solution. Kaolin is a mineral that is known to repel insects. It isn’t a sure thing, but it’s worth a try.
- Place floating row covers over your vegetable and fruit plants.
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About the Experts
Heather Stoven is an entomologist and associate professor with Oregon State University. She has a master’s degree in integrated pest management from the University of California-Davis.
David Price works an associate certified entomologist and technical director for Mosquito Joe, a nationwide pest control company. David studied urban entomology at Purdue University and previously served as vice president of the Central Virginia Pest Management Association.
