Gerrardstown, West Virginia, apple grower George Behling is one very concerned grower. He first saw this stinkbug two years ago, but didn’t distinguish it at first from ordinary stinkbugs, which have been a pest on his York apples over the years. This last year, the distinction became clear.
“The corking I sometimes saw on Yorks was nothing compared to this,” he said. “When you cut into the dings with a knife, what you see is not pretty.” The small pits on the surface are underlaid with corky tissue and brown streaks that run to the core.
Behling grows 70 acres of apples, and sells about 5 percent of them to customers through two farmers’ markets in Washington, D.C., 90 miles away. “I make half my income from those apples,” he said. “The other half comes from the 95 percent I sell for processing.” Apples that retail for $2.50 a pound—$100 a box—may sell for only $5 a bushel for processing into sauce.
Like many eastern growers, he finds the fresh market is a much better place to be, and direct marketing is even better. His customers, he said, will tolerate some defects, but “apples have to be decent.”
He found that damage appeared worse after storage. “So far, processors have given us a pass on damaged fruit, but I don’t know how long that will last. Apparently, they are able to make sauce, but apple slices are in big trouble. They look like the devil.”
Damage to peaches is a worse problem. There are few alternative markets for marred peaches. Behling also sells peaches, plums, cherries, apricots, pears, and raspberries. “They really tear up raspberries,” he said.
While he found Lannate and pyrethroids will kill the bugs, “insecticides are no solution at all,” Behling said. “They only kill the bugs that are there, and within a day, there’s a whole new flock of them.”
Penn State entomologist Dr. Greg Krawczyk says the same. “We can kill the stinkbug. But killing them doesn’t guarantee more won’t be back the next day. Pesticides are really not the answer.”
Behling said he has worked hard to develop IPM practices on his farm. “Pyrethroids kill the beneficial insects,” he said, echoing the concern of entomologists like Chris Bergh, Tracy Leskey, Dean Polk, and Greg Krawczyk, who say growers might face renewed problems with aphids, woolly apple aphids, San Jose scale, and mites if they have to go to a tight schedule of insecticide applications that kill predators.
“This was my third year using pheromone mating disruption on codling moth and oriental fruit moth,” Behling said, noting he had reduced sprays from 12 per season to five last year. “But why would I use them if I have to spray every week anyway?”
He’s hoping the entomologists can perfect some kind of attract-and-kill program. After all, they seem easily attracted. “I’m killing them every day in my house,” he said. “I looked under the insulation in my attic and counted 20 to 24 of them per square foot.”
Biological control may also be an option. Entomologists have gone to Asia looking for natural enemies. “Maybe a bird will develop a taste for them,” Krawczyk said, jokingly. These stinkbugs are said to smell worse than the native species.
Kim Hoelmer, USDA-ARS, has been researching the impact of natural enemies in the United States, as well as the potential of releasing parasitoids collected from the insect’s native range (China).
Egg parasitoids appear to be the most promising agents, and APHIS has obtained three species of Asian Trissolcus that parasitize the eggs of the brown marmorated stinkbug in Asia, which are in culture at its quarantine facility in Newark, Hoelmer reported. Parasitism of the bugs in Asia is typically high, at between 50 to 80 percent.