Good Fruit Grower

May 15

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Pfeiffer said the fly originated in a tropical climate and appears unable to overwinter in the northern areas of the United States. "It doesn't even overwinter in northern Florida," he said. "It has to move up from southern Florida each year." But the fly is able to move long distances, probably carried by the wind, he said. "I think what happens is it becomes aerial plankton and as air currents move, it's carried along by the wind." Because it needs to reestablish in northern fruit-grow- ing regions each year, Pfeiffer expects it will be a late-sea- son pest. Unlike spotted wing drosophila, the female fig fly has a weak ovipositor—the organ she uses to pierce fruit and deposit eggs—and so primarily infests overripe fruit or fruit that's already damaged. The insect came to Pfeiffer's attention when he and his colleagues were studying infested grape clusters in a Virginia vineyard. When they reared out the insects, expecting them to be spotted wing drosophila, 90 percent turned out to be the African fig fly. His hypothesis is that the fig fly is invading fruit injured by the spotted wing drosophila, which attacks less mature fruit on the tree, and this could happen with soft fruits as well as grapes. However, he doesn't see the two species working together to compound fruit damage because previous research with 27 drosophila species showed that the fig fly is one of the most competitive of all and would likely outcompete spotted wing drosophila. Pfeiffer and his colleagues are tracking movement of the African fig fly and studying the interactions between the species. They are also testing lures and baits to find out how attractive they are to each of them. The African fig fly has shown up in apple cider vinegar traps intended for spotted wing drosophila but not in high numbers. Sci- entists have been using mashed banana sprinkled with yeast as a bait. Dr. Peter Landolt, research leader and entomolo- gist with the U.S. Department of Agriculture in Yakima, Washington, who has developed a new lure for the spot- ted wing drosophila (see "A better fly trap"), has also worked on the African fig fly. Landolt said flies use volatiles as a way of seeking out their preferred foods, which differ from species to species. In lab tests, he exposed fly antennae of spotted wing drosophila, the African fig fly, and the common vinegar fly to volatiles of wine and vinegar to find out which spe- cific chemicals they were drawn to. Although there was some overlap, the most attractive blend of chemicals differed for each one. • GOOD FRUIT GROWER MAY 15, 2014 35 • Enter different row spacings: the controller automatically maintains your rate per acre. • Compensates for changes in ground speed. Automatic Rate Controller Option 400 gallon TTN profile Powerblast 400 gallon wheel-well Pulblast • 52" outside tire width w/11Lx15 tires • adjustable width wheel centers made in made in u s a u s a made in u s a Rears Airblast Sprayers POWERBLAST PULBLAST Interchangeable axial flow fans to match blade pitch and air volume to your application and horsepower. Electric fan clutch Rears Constant Velocity Hitch powers through 90° turns Rears centrifugal pump and Rears gearbox: manu- factured by Rears for more than 40 years. Simple pressure adjustment to maintain accurate calibration in different row spacings. This is a time tested design for a wide range of applications. Variable pitch fans available in 28" & 36" dia. 100 - 600 gallon units with tank profiles for your application. Rears Constant Velocity Hitch available for most Pul-Blast models Piston actuated diaphragm pump or Rears centrifugal pump. Heavy Gauge Stainless Steel Construction Spray tank and all tank hardware Tower casement, shrouds, steps Manifolds, louvers, air doors Fan and blower housing Agricultural Equipment Dealer information 800.547.8925 CHERRYBLOWER 15° Towers bring the nozzle closer to the spray target. Tower height and profiles to match your application. Tune air volume: adjustable air doors independently control target zones Match Rears' aggressive air delivery engineering to your application with Vertical Wall, Over-the-Row, or Grape Elbow towers. (At left) The tropical African fig fly appears unable to overwinter in cold climates, but re-establishes itself each year. "It becomes aerial plankton and as air currents move, it's carried along by the wind." —Dr. Doug Pfeiffer A map showing the distribution of the insect in the U.S. can be found at Cherries

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