Gardening: Pesky boxelder bugs
Because of a relatively mild winter and what looks to be a hot dry summer, this may be the year of the boxelder bugs (Boisea trivittatus).
You may think that because you don’t have a boxelder tree, you’ll avoid these pests, but Mother Nature may surprise you. These pesky ½ inch long dark brown to black beetles with red marking on their back and wings feed on the leaves of maples as well as boxelder trees.
If there is any good news about these critters, it’s they usually do little damage and for the most part they leave humans alone. So unless their presence drives you crazy, you can ignore them and in fall they will disappear. Or so you hope. It is this time of year they look for warm places to hide and if you have lots of ways for them to enter your house you may be targeted so sealing up possible entry points is a good place to start. When used properly, insecticides are another tool for control.
Large southern and southwest walls are preferred by these critters and it’s not unusual to see hundreds hugging the surfaces beginning in early fall.
A simple home-made spray made up of 2 Tbsp. of dish soap mixed with 32 ounces of water will kill these bugs on contact so you can use a hand or back pack sprayer to do them in. However, because the dish soap permeates the thin skeletal structure of the box elder beetle, it only works as a contact pesticide and is not effective as a residual pesticide.
To prevent these pests from entering the home, residual insecticides for use as perimeter sprays are available, however they may contain highly poisonous chemicals and are best applied by trained exterminators, especially if you have a large two-story house.
Borax, a white powder, once popular for use as a household cleaning and laundry product and available at most grocery stores, also breaks down the skeletal structure of boxelder bugs and can be sprinkled around the base of boxelder and maple trees and other areas where these pest gather.
Once they get into the house they only live but a few days, however they leave behind tiny red droppings that can cause stains on cloth and paper, so it’s best to vacuum them up ASAP. Be sure to empty the out the vacuum often as a large number of dead bugs will begin to smell over time.
Nancy Szerlag is a master gardener and a Metro Detroit freelance writer. Her column appears Fridays in Homestyle. To ask her a question go to Yardener.com and click on Ask Nancy. You can also read her previous columns at detroitnews.com/homestyle.