One reason I really enjoy living in the country is the opportunity to see nature up close: The woods, fields, streams and wildlife. A downside to country living is that sometimes nature wants to get closer than you want, as in they want to come into the house and hang out with you. We have had several unwelcome guests over the years: Mice, the occasional bat or bird and bugs…lots of bugs. Houseflies, blow flies, wasps, ladybugs and, of late, stink bugs.
Stink bugs have always been around. Growing up I remember running into green stink bugs in the garden or feeding on ripe wild blackberries, but they were never a serious nuisance. But in 1998 the brown marmorated stink bug (Halyomorpha halys), a China native, was brought to the U.S., probably a stowaway on a packing crate. It made it to our area around 2009. It’s an agricultural pest that does damage to soybeans and fruit crops. The bug is easy to identify, with a shield shaped body that is splotchy brown, and with antennae that have altering white and dark bands.
Their lifestyle goes like this: Overwintering adults come out in the spring, mate, and the female lays eggs on plants that will provide food. The eggs hatch in only four or five days into black and red nymphs that look sort of like ticks. As they grow they go through five instars (shedding of skin) and reach adulthood five weeks after hatching. This fast life cycle and lack of natural predators has allowed the bug’s population to spike quickly, especially in southern states where they can produce two to four generations in one year.
The brown stink bug is a problem for two reasons. One is that they overwinter using a tactic called diapause, going dormant in sheltered places until it warms back up. Unfortunately, they often choose our homes for the shelter, and can get in through pretty small cracks. Once in a warm house they become active and fly clumsily around lights making a nuisance of themselves. They aren’t hard to catch, except for reason number two, the stink. It’s a defense mechanism to dissuade birds and lizards from eating them. When disturbed or squashed, stink glands on the bug’s abdomen emit an ill smelling chemical (trans-2-Octenal in case you were dying to know).
So what to do? Sealing up your house as tight as you can make it helps, but for those that make it inside the best method I’ve seen to capture them is to build a light trap on the cheap. One style uses a 2-liter soda bottle and a battery powered LED light. Another style involves setting up an aluminum baking pan with soapy water and putting a spot light on it to attract the bugs to their doom. Instructions and videos are easy to find on the internet.
Steve Roark is the area forester in Tazewell for the Tennessee Department of Agriculture, Forestry Division.