Issue link: https://read.dmtmag.com/i/401644
26 NOVEMBER 2014 GOOD FRUIT GROWER www.goodfruit.com S ome Eastern fruit growers worked with research entomologists last summer to try to recover their Integrated Pest Management system, which was effectively dismantled when brown marmorated stinkbugs invaded their orchards four years ago. This year, using an effective new pheromone-baited trap that lures males, females, and nymphs, the researchers were able to evaluate a management scheme based on thresholds, a key concept in IPM. Instead of "keeping covered" with insecticides, growers monitor traps and treat with insecticide when a certain number of adult brown marmorated stinkbugs are found in a trap. The magic number seems to be 10. Dr. Tracy Leskey, the USDA entomologist who coordinates the nationwide Specialty Crop Research Initiative-funded project from the Agricultural Research Service Appa- lachian Fruit Research Station in Kearneysville, West Virginia, said things are slowly improving after the invasion of the stinkbug from Asia. Recalling the fall of 2010 and a panicky meeting in Bob Black's Maryland orchard where stinkbugs were visibly invading and nobody knew how to kill them, she thinks tremendous progress has been made since then. That year, the mid-Atlantic apple industry lost an estimated $37 million to the insect when apples emerged from storages with deep brown corky spots where the bugs had fed. The fear and panic is gone now—growers can control the insect—but the next step for growers is to undo the damage caused by having to spray with insecticides that have disrupted the biological control they had achieved using IPM. "We were able to mitigate the immediate threat by identifying the most effective insecticides," Leskey said. "But there were significant consequences, such as increased cost of inputs—as much as fourfold greater—and labor required for more frequent spraying. There were also increased costs from frequent outbreaks of secondary pests. IPM programs were devastated." Several insecticides are now used in spray programs, but none of them is ideal. Even when lethality is high, residual activity is low and impact on beneficial insects is also high. No insecticides seem to have much residual activity against the stinkbugs, making frequent applications necessary. In field trials in 2010, Leskey and her colleagues found that more stinkbugs were captured in baited black pyramid traps than in other traps, and that the traps were better placed on the ground than in the trees. In 2011, a known attractant pheromone (methyl decatrieonate) was found to be effective only late in the season. Then in 2012, a new two-component aggregation pheromone was found. Not only did this male-produced pheromone attract all ages and sexes but, when mixed with the attractant, there was a synergistic effect. "Sometimes two plus two can equal eight," Leskey said, "and that's what happened." Controlling the STINKERS Strides have been made against brown marmorated stinkbug. by Richard Lehnert New Equipment & Technology The brown marmorated stink bug is a major economic threat to fruit crops. ARS scientists are fighting back by developing traps, sequencing the bug's genome, and testing parasitic wasps as biocontrols.