Issue link: https://read.dmtmag.com/i/401644
www.goodfruit.com GOOD FRUIT GROWER NOVEMBER 2014 27 - Rozol paraffi nized pellets are ideal for wet conditions. - For use after Fall harvest, and before new Spring growth. - Perfect for use during snow melt-offs. Voles gnaw on tree trunks and roots (girdling) causing GLVUXSWLRQRIWKHWUHH¶VÀRZRIQXWULHQWVDQGZDWHU OUTSTANDING VOLE CONTROL Learn More Protect Your Orchard Ph: 888-331-7900 • www.liphatech.com Meadow vole. High-Density Orchards Require Intensive Vole Management with Armed with the new lure, the researchers last year set about matching numbers found in traps to damage found in orchards so they could determine threshold numbers that would trigger decisions to spray. "We advised growers to apply two ARM (alternate row middle) sprays seven days apart when the cumulative threshold was reached," Leskey said. "Growers are trying it this year, and so far it's going pretty well." This year isn't really a good test year because the cool, wet summer across the East, which triggered all kinds of rots, blights, and fungi, suppressed insect activity. By mid-September, however, all apple growers were reach- ing threshold levels of brown marmorated stinkbugs, she said. Trapping The entomologists are also working with four compa- nies that have found the incentive to manufacture the lures, which are nearly ready for commercial sale. The brown marmorated stinkbug has invaded Europe as well as North America, so traps that can monitor the insect will find a large market, Leskey said. The traps combine the visual stimulus of a black pyramid with the olfactory stimulus of the aggregation pheromone mixed with attractant. There is a capture mechanism that catches stinkbugs in an inverted funnel jar, where they are killed with a toxicant. Traps are placed along the perimeter of an orchard near places where stinkbugs are often found on wild hosts, usually in or near woodlots. In the test, the best threshold number was 10 adults per trap. Waiting for more to be trapped resulted in more injury, but treating too quickly—either when only one bug was found in a trap or when traps were ignored completely and growers just used a weekly spray—increased number of sprays and costs but didn't reduce injury. "A threshold of 10 adults per trap reduced insecticide applications by 40 percent with no significant difference in injury at harvest compared to weekly ARM," Leskey said. That conclusion was reached in 2013 in trials con- ducted in experimental orchard blocks, and this year growers worked with this provisional threshold to test it further. One thing the researchers noticed right away was that injury levels in trees nearest to baited traps were higher. "This is an aggregation pheromone," Leskey stressed. That means the trees with traps become much more attractive to the insects, which come there quicker and stay longer, leaving other trees less infested. "We found this combination lure not only attracted the bugs, it retained them longer—more than 20 hours," she said. "This gives them more time to forage and pick up a lethal dose of insecticide." The researchers had found that the stinkbugs fre- quently recovered after being poisoned if they did not get a lethal dose. In the trap trees, "if they started to recover, they were attracted again and received another dose." Leskey finds that "very exciting." The traps seem capable of doing double duty. Incor- porated into a lure or trap, the bugs can be counted and the result used to trigger an insecticide spray. Or they could be lured to target trees, where they can be killed in great numbers. Widespread The brown marmorated stinkbug is now considered a severe agricultural pest and a general nuisance to resi- dents in the mid-Atlantic states of Pennsylvania, Virginia, West Virginia, Maryland, Delaware, and New Jersey. It is also a growing problem in Oregon and Washington on the West Coast and in North Carolina, Tennessee, Kentucky, Ohio, and New York. It is a minor nuisance in Michigan, Indiana, California, Ontario, and five New England states. It has been found in 41 states and three Canadian provinces. • P eter Shearer, entomologist with Oregon State University in Hood River, will speak about the brown marmorated stink bug in the Pacific Northwest during the Washington State Horticul- tural Association's annual meeting in Kennewick on December 3.