Stink Bugs

You might not have heard of the brown marmorated stink bug, but chances are you'll see one soon enough. Honestly, I hadn't encountered one either until 2015.

There are local varieties of stink bugs, but these are native to Asia, where they're a significant crop pest.

In their natural habitat, they have a life cycle that produces one generation each year, with plenty of native predators to keep them in check. But in 1998, they were discovered in the U.S., and by 2010, they were causing significant crop damage to orchards, corn, and soybeans on the East Coast. In 2010 alone, they caused over $37 million in losses to tree fruit in the mid-Atlantic region.

Aside from crop damage, these bugs like to come indoors during the winter, and they can do so in incredible numbers. In 2012, over 26,000 stink bugs were collected from a single Maryland home over 181 days. When stressed, stink bugs release an offensive odor described as "dirty socks."

Females can lay up to 400 eggs in their lifetime, and in more temperate areas along the southern U.S., they can have up to six generations a year. 

Let's do the math: one fertile female, times 400 eggs, assuming 50% mortality and half are male, times six generations… that's 1 trillion stink bugs in one year! That's about 143 stink bugs for every human being on the planet from just one pair of stink bugs in one year!

Fortunately, there's a voracious predator that seems to have been accidentally imported along with the stink bug: the samurai wasp. This tiny wasp is so small it fits inside the egg of the stink bug. The female wasp lays her eggs in a clutch of stink bug eggs, and when they hatch, they consume the developing stink bug before it can hatch. In their native environment, these wasps are so effective that they regularly kill half of the stink bug population, and in good years, up to 80%.

With any luck, this predator will keep the stink bug at manageable levels, but if they come to your neighborhood, it may be necessary to treat every year in early fall to reduce the number of stink bugs that enter your living space over the winter.