Good Fruit Grower

October 2011

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Growers battle STINKBUG Mid-Atlantic growers reacted aggressively this year after huge losses in 2010. By Richard Lehnert R ice Fruit Company installed new defect sorting equipment in its apple packing operation ear- lier this year—making a sizable investment in anticipation of another onslaught from brown marmorated stinkbug. "We're hoping it's unnecessary," said John Rice, vice president of sales and marketing for the company. "We don't know yet. It's late August, and the worst damage last year occurred late in the season." Located in Gardners, Pennsylvania, just slightly north of the core stinkbug infestation, Rice Fruit got a rude wakeup call last fall. "We quite honestly were not anticipating the kind of damage we saw," Rice said. "We were surprised by how much damage there was in the fruit our growers put into storage. We could see how prominent the stinkbug became the last few weeks of the season. Our windows Eastern peach growers report having greater success in controlling the brown marmorated stinkbug this year than they did in 2010. here at the packing plant were covered with the bugs, and we knew the situation growers were facing." Mark Seetin, the director of regulatory and industry affairs for the U.S. Apple Association, pegged damage to the 2010 apple crop in the Mid-Atlantic states at $37 million after a survey of storages last winter. "The worse damage was to the south of us," Rice said. "There, some growers had 70 to 80 percent of their fruit damaged—and whole lots went straight to juice. Other growers had less injury. Overall, 10 to 15 percent of our apples were damaged." Seetin estimated apple losses in the region at 18 per- cent of the crop—ranging from 5 to 10 percent to almost 100 percent in some orchards. Like Rice, he said the bug exploded in 2010, after some years of a slow buildup and reports of scattered damage in 2009. Stinkbug damage on apples shows up as visible, dark- ened depressions in the skin underlain with corky tissue that can penetrate deep into the apple. This made dam- aged apples unsuitable for processing into slices and sauce, Rice said. Luckily, the market for juice apples last year was better than it had been in some time. The new sorting equip- "On the positive ment can detect those damage spots, making it possible to salvage good apples from damaged lots. Last year, sorting was done by hand. A wet May this year resulted in more apple scab lesions than usual, Rice said, so the equip- ment will be a good invest- ment, whether or not the stinkbug does damage. Nervous concern Several things con- side, I still see green lacewings in the orchards, so we're not killing all our tribute to the nerve-wrack- ing situation this year. According to Pennsylvania State University entomologists Dr. Larry Hull and Dr. Greg Krawczyk, fresh injuries from stinkbug feeding are ini- tially almost undetectable, but become apparent after a few days. Since they feed under the skin of the fruit, it is only after the affected cells start drying that the symp- toms of their feeding (corking) become visible. If feeding occurs just before harvest, the symptoms might not be apparent until after the fruit is in storage. A second concern is the lack of an effective and stan- predators." —Bob Black dardized monitoring tool, according to entomologist Dr. Chris Bergh at Virginia Polytechnic Institute and State University. Growers and researchers have used various kinds of traps, but the number of captures hasn't been translated into damage estimates or action thresholds. This year, growers reacted by aggressively spraying when the bug was first detected. Researchers are looking for effective pheromone lures and studying the reaction of the bugs to various intensities and wavelengths of light. A third concern going into this season was the lack of field testing on insecticides. Growers entered the season armed with insecticides tested only in laboratory bio - assays. "None had been systematically tested," Bergh said. It also wasn't known how long a residual effect insec- ticides might have. Growers reacted by increasing the frequency of sprays and depended on contact to kill the bugs, which was probably the best approach, Bergh said. "In our prelimi- nary studies, we didn't find insecticides with good residual activity." Bergh thought growers had achieved better levels of control this year. "For many, however, it inflated their insecticide costs 25 to 30 percent and more. Is that a sus- tainable cost? That's a good question. But it gave them some confidence that the bug can be controlled." 6 OCTOBER 2011 GOOD FRUIT GROWER www.goodfruit.com Tracy Leskey, UsDa

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