* * Stink bugs are worse than you think

Brown marmorated stink bugs. Yes, they are awful. But they may not be as bad as a biblical plague, according to Tom Kuhar, professor of entomology at Virginia Tech. We got together recently to talk about the infestation that we see in this area, how it came about, and where he expects it to go over the coming years.

The stinkbug that is now clinging to the screen on your window, looking for a way to get in for the winter, is descendent of a hitchhiker that likely arrived from China in a shipping container, some 25 years ago. Tom said, “We can literally track it into the Beijing area.

“Entomologists have run the DNA and tracked it to that specific area in China. All the bugs in eastern and central United States are genetically similar to those in that part of China. Other populations of this invasive species have entered the United States on the West Coast. “You could not design an insect that would have a better chance of hitching a ride in a shipping container and making it here.”

Tom is originally from Baltimore and attended college at Towson University before earning his graduate degrees at Virginia Tech. He said, “I fell in love with insects at Towson and went to Tech because of their entomology department.

“I fell in love with this area the second I got here; I loved everything about it. Growing up in Baltimore, I was really surprised to become so interested in the agricultural side but I realized that I could help a lot of people by better understanding insects. I could learn to answer questions for growers and other people who are affected.”

He started his career with Virginia Tech at a research facility on the Eastern shore, but eventually landed a position on campus in Blacksburg. He supervises graduate students who are working with a variety of different insects.

Stink bugs are particularly insidious and nasty because of the defensive odors that they produce when bothered; when you squish them, they smell awful. They get into everything, even the smallest spaces. They winter in sheltered places like your house. They are undoubtedly living in your house as you read this.

“Ninety percent of the issue of the stink bug,” Tom said, “is that they are a nuisance for everybody. But they are particularly damaging to farmers, especially those who grow fruits and vegetables. I was in an older house that had an open attic in Harpers Ferry, West Virginia in 2010. The owner was a scientist. He was meticulous with his record keeping. He killed that year hundreds of thousands of stink bugs. They seek shelter and then they aggregate into large masses that may contain thousands of bugs.

“There have been some wineries that had to close down their wine tasting in late September because of all the bugs swarming around. The bugs can get crushed with the wine grapes and possibly taint the wine depending upon the type.”

“From an agricultural standpoint, they can be absolutely devastating. Stink bugs eat by piercing fruit or pods with stylet type mouthparts that inject digestive enzymes that liquefy the tissue, which can be sucked up by the bug. You can’t always tell if an apple is damaged until you cut into it and see these ugly brown channels in the meat. A wholesale apple grower may find this in a few samples from a particular grower and he will reject the entire crop. This is devastating to the orchard owner.

“Soybeans, corn, vegetables, grapes, there are many other commodities that are equally at risk. Mitigations have included insecticides and physical netting over the plants to keep the bugs from reaching the fruit. Scientist learned that there is an aggregation pheromone that attracts these bugs. So they can put this on select trees, effectively sacrificing those trees in favor of the neighboring trees.

“We will never fully get rid of stink bugs. They are a fact of life, here to stay. They are prolific breeders. They feed on many different types of food crops. They travel significant distances. They are opportunistic and they go where the best food is. But they are not invincible. They do not tolerate heat very well, and they do not tolerate extreme cold.” If bugs did not find sufficient shelter, many will not survive the winters in our area. Unfortunately, they are adept at getting into cracks and crevices.

“Ironically, another invasive bug has arrived from China that may prove to be the stink bug’s worst enemy, a tiny wasp that lays its eggs inside the stink bug’s eggs, killing them. “There has been some good news. 2009 was the worst year for pest problems in Virginia. Since then, Mother Nature appears to be taking care of it in different ways. Things have not been as bad since.”