Growers vs. stink bugs: learning effective chemical use

In the years since brown marmorated stink bugs began creeping into the Northern Shenandoah Valley, farmers and growers have been doing what they can to reduce damage to their produce.

Dudley Rinker owns Rinker Orchards in Stephens City and grows a variety of apples – the bug’s dinner of choice – for company supply, “pick your own” visits, cider making and direct sale. He said he began noticing the bugs around six to 10 years ago, and said that “there were definite losses, but then we used what we had.”

“It was gradual…and just built up over a couple years,” he said. “You still find the little suckers.  Over the next several years more research was done, so we’re able to start zeroing in with particular materials. It’s one of those things where we’ve worked hard for years on our IPM (integrated pest management) programs and all of the sudden that went out the window just to protect yourself from the stink bugs.”

Despite wanting to keep insecticide use to a minimum, Rinker said he isn’t aware of alternative methods of control. He said he holds off on chemical use until the end of the apple blossom bloom to reduce harmful effects on bees. The first treatment usually occurs sometime around mid-May.

John Marker is a partner owner of Marker Miller Orchards in Winchester, which grows apples and peaches – another stink bug favorite. He said that while apples that the bugs have blemished may not be prime for the market, they can still be made into cider. However, he said a pound of those apples is worth significantly less than a pound of marketable ones.

“You still used them for cider or something like that, but 98 percent of apples that are sold fresh go by appearance,” he said.

He also said that the bugs foiled any integrated pest management plans, which would’ve otherwise helped to cut costs since the chemicals are expensive. Still, he said learning more about the bugs’ life cycle has allowed him to use insecticides more effectively.

Marker said certain kinds of parasitic wasps – the bugs’ natural enemy – have been discovered in the area. He said he hopes the wasps can become a natural method of stink bug population control in the future, so long as they don’t harm other insects.

“The brown marmorated stink bug has really cropped up fast to be a major pest,” he said. “We’re hoping that we can keep those numbers down.”

Bobby Clark, Virginia Cooperative Extension agent for agriculture and natural resources, said that the bugs have only been a small problem for corn and soybean growers, not necessarily causing costly damage year after year.

The bugs can also be an indoor nuisance; settling into homes in the fall to wait out the winter. While they haven’t been known to damage structures, they can be irritating when flying into lights as they try to leave a home to lay eggs.

Mark Sutphin, Shenandoah extension agent for agriculture and natural resources, said solutions to the bugs’ home invasion remain pretty inelegant.

“From the home aspect, at least as a pest indoors, our existing recommendation is still to vacuum them up once they’re indoors,” he said. “There’s really no benefit from applying pesticides in the home.”

Sutphin said homeowners and growers alike are still developing and sharing best management practices as the bugs’ invasion continues to spread.

“It’s a learning process for all because it’s a fairly new pest and a widespread pest in the home residence, in the home landscape and garden as well as an agronomic pest,” he said.

Contact staff writer Rachel Mahoney at 540-465-5137 ext. 164, or rmahoney@nvdaily.com