Good Fruit Grower

March 1

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A video of the flight mill can be viewed at www.goodfruit.com. Left center: Predators of the brown marmorated stinkbug include crabronidae wasps that grab and paralyze stink bugs and haul them back to their nests to feed to their young. Inset: An egg mass of the brown marmorated stinkbug with newly emerged first-instar nymphs. Unlike other stinkbug species that move into orchards as the fruit matures and then leave again, the brown marmorated stinkbug can spend its entire lifecycle on fruit crops. In northern regions, it has just one generation per year, but as it extends its range to warmer areas, such as Florida, it could develop through as many as five generations annually, Shearer said. Hosts The bug���s host range seems to know no bounds. All tree fruits and small fruits appear susceptible. Shearer said the bug has attacked filberts, piercing the husks and shells to damage the nuts inside. Bugs were seen in commercial vineyards, hazelnut orchards, and caneberry crops in Oregon for the first time this year. Scientists at OSU and the University of Maryland are looking at how bugs might contaminate wine if they get into the crush. The bug has also been seen infesting hop plants, which Shearer said might mean doing similar research on beer contamination. It also likes ornamental plants. Wiman has been monitoring the bug���s distribution in the Northwest by visiting different regions and walking the streets checking potential host plants. A smartphone app tracks and maps where he���s walked. English holly is the most common host he���s found, along with maple, lilac, cherry, and the tree of heaven. Shearer said English holly was imported into Oregon as an ornamental and cultivated for cuttings for the holiday season. Many of the holly farms have closed and been replaced by housing or vineyards, but the plant���s seeds are spread to other locations by birds, and it is now regarded as an invasive species. photos by nik wiman, oregon state university Monitoring ���We could be underestimating how important flight is in this pest���s dispersal.��� A team of more than 50 investigators from 11 institutions across the country is working on a project to find ways to manage the pest. The project, led by Dr. Tracy Leskey at the U.S. Department of Agriculture in Kearneysville, Virginia, has funding from the federal Specialty Crop Research Initiative. USDA scientists have been developing monitoring tools that could alert growers when bugs arrive in orchards. They have identified an aggre���Peter Shearer gation pheromone from the stinkbug, known as ���odor #10��� that appears to be effective as a trap lure. They���re also exploring the possibility of using white, black, or blue light to attract bugs to traps. So, what does a grower do if the bug shows up? Shearer said it���s difficult to kill with chemicals, and the chemicals that do kill it are the broadspectrum products that kill everything else���pests and beneficials alike. ���It has put a damper on IPM [integrated pest management]���, he said. ���The saving grace will be biological control.��� Researchers believe biocontrol will be the safest, most effective, and economical approach to tackling the bug and are assessing natural predation and parasitism of the stinkbugs. Wiman found a native parasitic wasp, Trissolcus cosmopeplae, that lays its eggs in brown marmorated stinkbug eggs. When the young wasps hatch inside the stinkbug eggs they consume and destroy them. Researchers hope that over time, native stinkbug egg parasitoids will increasingly turn their attention to the new invader. Stinkbug predators include crabronidae wasps that grab and paralyze the stinkbugs and haul them back to their nests in the ground to feed them to their young larvae. Scientists are also looking for natural enemies of the bug where it originated in China, working on the theory that if the bug is not considered a threat there, it might be held in check by biological control. A parasitic wasp called Trissolcus halyomorphae was imported from Beijing and is in quarantine at OSU where scientists are conducting tests to make sure there would not be unforeseen problems should it be released into the environment. ���We���re hoping biological control will help control it,��� Shearer said. ���If not, this pest will set back our IPM programs at least 50 years.��� ��� The stinkbug injects saliva into the fruit and then sucks out the juice, causing brown areas in the flesh that can resemble bitter pit. GOOD FRUIT GROWER MARCH 1, 2013 25

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