Stink bugs growing in number

Local populations of the brown marmorated stink bug are on the rise

By Patty Hastings, Columbian breaking news reporter

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photo An adult, left, and juvenile, below, brown marmorated stink bugs. Local populations are on the increase, and gardeners have taken notice.

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Pest Watch: Brown Marmorated Stink Bug

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Something stinks in Clark County — and it's only the size of a man's thumbnail.

Local populations of the brown marmorated stink bug are on the rise, making their presence known by damaging crops and letting off an intense odor that's described as freshly ground coriander.

"Once you smell it, you'll smell it all over the place," said Todd Murray, Washington State University Extension director for Skamania and Klickitat counties.

The local Master Gardener answer clinic has been flooded with calls, emails and visits from people who have herded these garden pests into mason jars. The mottled brown and gray bugs are relatively new to Clark County, but already causing a stir among area gardeners.

The bugs feed on about 300 types of plants. They use their straw-shaped mouth piece to stab plants and suck up the juices, leading to deformed leaves and dark, spongy blemishes on fruit.

"To add insult to injury ... pretty much all plants we like, they like also," said Murray, who is leading research efforts on ways to trap the stink bugs.

As the weather continues cooling down, large groups of the bugs will seek shelter on the sunny side of houses or find their way inside through cracks and crevices; they can enter homes by the hundreds or thousands. They don't sting or bite, but they're very fast, and as adults they can fly. Like most bugs, they like to crawl into small spaces and could end up in a car's weather stripping.

"We could see some uncontrolled populations here," Murray said.

While Murray has yet to hear many reports from commercial growers, the bug has the potential to taint produce harvests from their odor alone, which they release when scared or crunched under a shoe. The best way to deal with them, according to the Master Gardeners, is to vacuum them up or scoop them up into a sealed plastic bag and dispose of them. Homeowners should also seal any cracks or crevices the bugs might want to crawl into. There is no recommended insecticide, and repopulation occurs quickly.

Murray predicts that in the next few years, natural enemies will feed on the brown marmorated stink bug, populations will be kept at bay and researchers will develop solutions to deal with these pests. The bug first invaded the eastern seaboard, damaging a wide range of crops in 2009 and 2010. They were first identified in Vancouver in 2010 and have started to spread to the edges of the county.

Anyone who sees these bugs outside of Clark and Skamania counties is asked to take them to their local Washington State University Extension office.