Most of you don’t realize it, but Cold Climate Gardening is host to a secret club, the Stink Bug Haters Club. It all started innocently enough with this post. But as more and more stink bug sufferers found the post and took advantage of the Subscribe to Comments feature, it started to take on a life of its own, with the various visitors sharing disgust and stink bug capture and killing tips. I haven’t had much trouble with these bugs myself, but I’ve always wanted to provide the people who’ve been commenting with more information. I finally tracked down some experts, Amanda Koppel and Dr. Kim Hoelmer, to write a guest post.
The changing of the seasons: spring brings with it new growth, summer brings the hot sun and swimming, fall is the harvest and a touch of cold, and winter… snow! But when the temperature starts to drop, you might find another visitor besides Santa Claus in your house.
Where Did They Come From?
The brown marmorated stink bug, Halyomorpha halys (hereafter abbreviated BMSB), is an invasive species of stink bug native to China, Korea and Japan. It’s thought that BMSB first came to the United States in shipping containers arriving from Asia. The bugs were first identified in Allentown, PA in 2001, although they probably arrived here several years earlier.
Where Are They Going?
Since becoming established in Pennsylvania, the bug has spread throughout the Mid-Atlantic states as far south as Virginia. It’s also been spotted in several southern and midwestern states, and has become established on the west coast in Oregon. It’s still on the move! Since they are strong fliers, BMSBs may fly to a new habitat, but many hitch a ride in shipping containers or on cars.
How Stink Bugs Bug People
In autumn, the adult stink bugs aggregate on and inside houses, sheds and other structures looking for a warm place to spend the winter. Many people find this to be a nuisance because the BMSB gives off a characteristic odor when they’re crushed or disturbed. However, this bug might pose a threat to your plants, too. BMSB has been reported on 73 different plant species in Pennsylvania alone, including butterfly bush, lilac, buckthorn, tomato, and grapes. Feeding on most ornamentals is probably innocuous, but various kinds of fruit crops can also be damaged by BMSB feeding.
What Can You Do?
So how can you protect your homes and gardens? Caulking or physically sealing cracks around doors, windows and attic vents are the most effective methods that help to prevent them from entering, and eliminating weeds around your house will decrease temporary harborages. BMSB is a small insect, so it’s important to be diligent about sealing every opening or they still might find ways to squeeze in. You can also hire a professional pesticide applicator to spray insecticides around the outside of your home during the fall months when the stink bugs are looking for places to spend the winter.
Currently, there are no federal quarantines in place to prevent the spread of BMSB. Since the BMSB hasn’t become a major agricultural pest yet (although it’s believed that it could, based on its known host plant range), there are no established control methods for eliminating them from your garden. Picking them off your plants or catching them on sticky cards are two possible ideas. Pheromone traps for this insect are under development but are not yet available commercially. Most stink bugs are attacked by a variety of natural enemies, especially insect predators and parasitoids. Research has shown that native North American beneficial insects don’t show much interest in BMSB, however, and there are no commercially available beneficial insects that effectively attack BMSB. USDA entomologists are studying the feasibility of introducing effective BMSB natural enemies from Asia that are safe and specific to the stink bug and which would offer some long-term relief.
I know a lot of the commenters have already tried sealing up their homes to little effect. Many are desperate enough to try any kind of poison to get rid of these pests. So, on behalf of stink bug victims everywhere, I decided to ask a few more questions:
Do you know much about the pesticides that a “professional pesticide applicator” would use? Could you elaborate on why it should not be a DIY job to spray these chemicals?
AK: A pesticide applicator would likely spray an insecticide from the pyrethroid class. Examples of pyrethroids include deltamethrin, lambda-cyhalothrin, and cyfluthrin.
This is not a do-it-yourself job! There are laws associated with pesticide application. For example, it is illegal to apply pesticides contrary to what the instructions on the label say. Further, it’s illegal if you allow your pesticide to drift onto things for which it’s not intended.
Even more important, pyrethroids are neurotoxins, and improper spraying can be very hazardous to your health. For example, if your skin comes into contact with deltamethrin, it can lead to redness, and facial paraesthesia can result if it comes into contact with your mouth or eyes. It’s best to let a trained professional handle these chemicals.
The website from which the commenters are buying pesticides provides this article on the stink bugs. Would you say it is accurate?
AK: I’d say it’s exaggerating a few facts. This bold statement from the site, Don’t be misled into thinking any stink bug is a good bug bothers me, because the spined soldier bug (Podisus maculiventrus) is a good guy! The spined soldier bug is NOT destructive and, in fact, eats a number of pest caterpillars in gardens and commercial crops.
Also, Try not to handle them and be careful if you do – not only will they release that nasty smell but many species are able to inflict a nasty bite! was a bit funny, since I’ve been working with stink bugs for 4 years and have never been bitten. Stink bugs don’t even have mandibles; they use a long “beak” (a tube) to pierce through the skin of fruits, veggies, and crop plants and suck out their food.
And, Stink bugs leave strong odors which linger for 6 months or more, makes little sense to me. I’ve had hundreds of collected stink bugs from wheat in a Ford Explorer, and their stink is gone from the car in 2-3 days.
It’s important to remember that one purpose of that webpage is to sell a product.
KH: Also, the website mistakenly implies that most of the stink bug species are capable of acting as pests in gardens/orchards. This is not the case at all. Only a handful of stink bug species are ever pests. Most species are completely innocuous as far as human interests are concerned. One additional error of fact in the ‘bugspray’ site – BMSB will NEVER EVER reproduce inside a home or structure. This occurs only on the host trees or shrubs, and only during the summer months. Bugs in the house during fall and winter are just hanging out, waiting for spring and the opportunity to return to the outdoors. You will only see adult BMSB entering your home, never the immature stages.
What do you know about cypermethrin, baygon, and deltamethrin, the three pesticides recommended by the aforementioned site?
AK: I mentioned deltamethrin above. Cypermethrin is used in household products to control ants and cockroaches. Baygon is another name for a number of pyrethroids used together.
Do light traps actually do much?
AK: Light traps aren’t a terrible idea, but I’m not sure how effective they would be. On the farm, we have a blacklight trap which we use to monitor for stink bugs. Based on the number of stink bugs caught, we estimate how many bugs might be in nearby fields. However, this is NOT for BMSB, and it doesn’t control large populations at all.
KH: When light traps (or their lethal cousins the bug zappers) are used indoors or in enclosed patios, they can be very effective at eliminating the insects in the immediate area. However, when they are outdoors and open to being seen from a distance, it’s important to remember that THEY ARE VERY ATTRACTIVE and even though they may trap or kill large numbers, they are attracting a larger number of stink bugs from further away to your home or yard than would have arrived without the traps being there!
For More Information
Compiled Anecdotal Wisdom from Commenters on the First Stink Bug Post
From Penn State University: Brown Marmorated Stink Bug Entomological Notes (pdf)
From Ohio State University: Brown Marmorated Stink Bug Fact Sheet (pdf)
From Rutgers University, New Jersey: Brown Marmorated Stinkbug – A Non-native Insect in New Jersey (pdf)
From The University of Florida: Featured Creatures: Brown Marmorated Stink Bug
NEW! Stop Stink Bugs – a site devoted to the cause.
Amanda L. Koppel, Dept. of Entomology, Virginia Tech, Blacksburg, VA
Dr. Kim Hoelmer, USDA-ARS Beneficial Insect Introductory Research Lab, Newark, DE