What is a Stink Bug?
The stink bug is a brown or green pest that has found its way to the North American continent from its indigenous homelands of China, Taiwan, Korea and Japan. The first known instance of the Brown marmorated stink bug in the U.S. was recorded in eastern Pennsylvania in 1998, meaning that the bug had likely found its way overseas a few years earlier.
The stink bug is of the family Pentatomidae and the insect order Hemiptera. Most scientists believe that its characteristic odor is the bug’s main defense against predators. Produced from special glands in its abdomen, this smell is actually a chemical that can be slightly poisonous if ingested in large enough amounts.
All types of stink bugs have a unique “shield” body shape. They can fly, and when standing still, the wings cover the body. Their relatively long legs extend outward from the body, and the adults are around 0.5″ long. Though described scientifically by their brownish color, stink bugs actually come in many different hues that can change over a lifetime. The most common coloration is green or brown, and some species are colored brightly. Most of these insects have white undersides and multicolored legs. Nymphs, or immature stink bugs, can come in colors ranging from yellow to black. Stink bug nymphs may actually be mistaken for adult ladybugs. However, their backsides are striped rather than dotted with black overlays.
Damage from Stink Bugs
Aside from their odor, stink bugs are pests that can destroy agricultural crops. These bugs feed on plants of all types and will adapt their feeding habits to an available plant species. They have been enough of a threat to warrant official government attention for many years. Because they attack plants in swarms, they can do extensive damage quickly.
In 2010, the stink bug epidemic caused over $37 million in damages to mid-Atlantic farmers. Their favorite crops tend to be grapes, soybeans, apples, peppers, peaches and tomatoes: they alight on fruits and vegetables and suck the juice from the plant from the outside. Fruits that have been attacked by stink bugs will showcase white, green or yellow discoloration at the point of entry, and the fruit may also knot up.
While the stink bug does have natural predators, the insect has far outpaced the population of those predators in North America. Their numbers are already so large that pesticides might actually cause more harm than good if applied on the scale necessary to control them.
Inspecting for Stink Bugs
Relatively large for an insect, a stink bug can be easily spotted once you can identify it. However, if you see a few stink bugs around your property, you may have hives of them in a slightly less noticeable location. Here is a short list of places that stink bugs make a home:
- Window and door frames
- Vents and eaves, especially those with exposure to the sun
- Any cracks and crevices in your home’s infrastructure
- Folds in drapes
- Hollow curtain rods
- False ceilings
Stink bugs generally try to access the sun. They will move outside as weather gets warmer during the year. Some researchers claim that stink bugs are also attracted to—and will try to nest around—blue, white and black light. They also tend to be attracted to certain pheromones.
Begin monitoring your home for stink bugs in March or April. Begin by checking common host plants (which you can plant in sampling blocks specifically for this purpose)—especially the bases of the plants. This is where wintering bugs will hibernate. The host plants that stink bugs prefer are dock, mustard and mullein. If you cannot find these, you may check on velvetgrass, thistles, morning glory, mallow, milkweed, plaintain, and vetch. If you find more than five bugs a piece on the host plants, then you probably have an infestation, and you may need professional assistance. Researchers recommend resampling host plants in about a week if you find fewer than two bugs on the host plants.
In June and July, you can sample for stink bugs by looking for damaged fruit and vegetables. Take samples from the plants that are on the border of your property. If you collect stink bugs directly from these plants, move to the next step in testing. Examine the blossoms of the fruit for bugs, excrement or discolorations. If you find more than three blossoms that have been affected in a half hour, then you have an infestation.
Managing Stink Bugs
Your stink bug management approach depends on the vegetation around your home and the level of infestation your property has incurred. Keep in mind that most stink bug infestations will occur near uncultivated areas. Stink bugs love to move to ground covers in the weeds where uncultivated areas dry up. Therefore, your first step is to cultivate the area around your property as much as possible
You may have to take extra steps if you grow crops that stink bugs prefer, such as corn, berries, alfalfa, and wheat. Keep your gardens and orchards free of weeds, especially if you have these crops on your property. One of the biggest mistakes that you can make is to try to mow the weeds where stink bugs reside. This will not get rid of them; the bugs will simply move into adjacent trees.
The following treatments have been proven effective in controlling stink bugs. If you are not sure about how to apply the pesticides listed, you may have to employ professional help.
Fenpropathrin or Clothianidin during the peak bud and bloom seasons – should be applied liberally, drenching the ground with a spray to cover the entire crop at once. Professionals recommend using from 100 to 300 gallons of water per acre when applying these treatments.
Fenpropathrin should be applied as soon as any stink bug activity is noted. The higher concentrations of this pesticide should be applied in the instance of higher pest concentrations. Clothianidin should not be sprayed directly onto a crop nor allowed to drift onto any other crops. Both pesticides are highly toxic to bees.
Fenpropathrin or Clothianidin during May, June, or during preharvest months. During these seasons, apply these pesticides to trees. Start applications when the first stink bug activity is noted, using higher concentrations for more severe infestations. To protect bees, make sure that you do not allow the pesticide to drift onto neighboring weeds or crops.
Trapping and Baiting/How to Make a Stink Bug Trap
A Virginia Tech study found that homemade stink bug traps were actually more effective than professional traps. Depending on the scale at which you need to trap stink bugs, you may be able to utilize the following DIY solution:
- Use the stink bug’s natural attraction to certain types of light, as well as certain pheromones. Use a desk lamp with white, black or blue light to bring the bugs to a specific location where you are setting the trap.
- Put a pan of soapy water underneath the desk lamp. The stink bugs should begin to come to the pan after about 12 hours. The soapy water will kill the bugs.
The advantage of a DIY trap like this is that it is pesticide-free. However, it is only effective for smaller scale problems. For larger infestations, you may need a professional solution. You can find various stink bug traps for different environments that use electricity, sticky surfaces, and smells.
Place traps where stink bugs are likely to congregate. Keep in mind that these insects tend to form nests outside during the summer months and inside during the winter.
How to Keep Stink Bugs Away
The best treatment for stink bugs is to prevent their appearance in the first place. If you know that your land is probably going to be attacked, there are some easy solutions that will keep your home and property safe:
- Seal your windows and doors. Stink bugs love to make nests in the damaged linings of doors and windows. One of the easiest ways to get rid of them during the winter is to ensure that all of your doors and windows are properly sealed. Repair any torn window screens. Vent your attics and crawl spaces. Weather strip your doors and caulk your doors and windows.
- Note outside entryways and inspect your property at least once every three months to find any cracks that stink bugs can use as an open door to your property.
- Vacuum often. Stink bugs can be physically removed from walls and windows with a simple vacuum. Keep in mind that if they have already released their odorous chemical, the smell will linger for some time.
- Wash your plants. The first time that you see a stink bug on tomato plants or apple trees, spray them with water directly. This will physically force the bugs from the plants. For a more long-term solution, mix water with vegetable oil, lavender oil or olive oil. Use a garden sprayer to apply this treatment.
- Plant distraction crops. Give stink bugs a place to congregate away from your cultivated crops. Because stink bugs are attracted to yellow, you can plant sunflowers, mustard, millet, garlic, or lavender. Doing this will also attract more of the stink bug’s natural predators.
- Cultivate your gardens by controlling your weeds. Simply taking care of your garden will help you to control your stink bug population. These bugs love to move into your territory on weeds that are unattractive to gardeners in the first place. Control weeds until harvest to reduce your stink bug problem naturally without having to use pesticides.
When to Call a Professional
Despite the many do-it-yourself solutions for stink bugs, sometimes the sheer size of the infestation may be too overwhelming. If you continue to find the same number of stink bugs after treatments and waiting a few months to retest, a larger-scale solution may be necessary. Call a professional exterminator if the population around your property outpaces your ability to control them.