Issue link: https://read.dmtmag.com/i/263110
www.goodfruit.com GOOD FRUIT GROWER MARCH 1, 2014 21 any given insecticide and some disease control materials, too. What can I spray today? Check the chart. Last year, technicians at Whalon's lab studied five insecticides— in four different classes—to see how long it took for residue lev- els to fall below an acceptable maximum residue level. The levels were chosen to conform to the demands of different countries that might be final markets for the fruit. Maximum residue levels are not uniform around the world. "We studied the worst first," Whalon said. By worst he means insecticides that would be applied close to harvest to kill insects such as spotted wing dro- sophila or obliquebanded leafroller. Leafrollers are a special problem in tart cherries because their larvae can fall into a shaker-harvested tank of cherries. The tolerance for worms in processed tart cherries is zero. Test trees were sprayed at different rates and different dates relative to har- vest, and fruit was harvested, frozen, and sampled for residues at 7, 14, and 21 days after harvest. This year, he hopes to study different methods of handling harvested fruit. Tart cherries, for example, are han- dled in tanks of cold water, and water degrades many pesticides. "One of the reasons we always liked Guthion [azinphos-methyl] was we knew we could destroy it on the cooling pad," Whalon said. "Residues were never a problem with that insecticide when cher- ries were held in a cooling tank for two hours or more." The results—just one year's data col- lected from samples from three-tree treatments replicated three times—were charted on graphs. When similar studies were available, the chart included data from two arid growing regions in the West. The researchers found the break- down patterns can be quite different in dry growing areas than in the wetter areas of the East. "Many times, fruit in dry cli- mates retains residues longer than fruit in wet climates," he said. Insecticides The insecticides that were studied included: —Assail (acetamiprid): A neonicoti- noid insecticide, which broke down rel- atively quickly and presented few MRL issues. —Delegate (spinetoram): A spino- syn insecticide, which also broke down quickly. —Imidan (phosmet): An organophos- phate insecticide, it initially broke down steadily, but the degradation slowed and residues persisted above the low max- imum residue levels required in some markets. "I want to really caution you about using this product close to har- vest," Whalon said. "And definitely do not send this fruit to Japan." —Mustang Max (zeta-cypermethrin): A pyrethroid insecticide that also showed a lag in the final breakdown phase, typical of some synthetic pyrethroids, Whalon said. Again, use should depend on the maximum residue level in the recipient country. —Danitol (fenpropathrin): This pyrethroid showed a very long decay pattern that could trigger an maximum residue level problem if the material was used too close to harvest. Whalon's lab has funding now to continue to develop these profiles on more insecticides during the coming year. • 1615 W. Ahtanum • Yakima, WA 98903 • 509-248-8785, ext. 612 For the representative nearest you, visit our Web site: www.orchard-rite.com Get the Orchard-Rite® story from your nearest representative: A s the operations manager for Pride Packing, I am responsible for managing 2,800 acres of orchard under 260 wind machines. Of that, approximately 1,000 acres are in stone fruit with the remaining acreage in apples and pears. From November to February, we can deal with arctic events that will take our temperature into the single digits—and even subzero. I really don't think it's possible to grow stone fruit economically in the Yakima Valley without wind machines. This last year, we would not have even had an apricot crop without them. All of our wind machine purchases since 1982 have been Orchard-Rite. In the wintertime, when we're starting these machines, the temperatures are usually single digits to subzero. We depend on—and have complete confidence in—our Orchard-Rite ® Wind Machines and the service we receive. We still have the first Orchard-Rite ® Wind Machine we ever bought! We're real believers in the Auto Start option. We order Auto Start on all our new machines. To date, we've retrofitted about 50% of our old machines, and plan to put the Auto Start on the remaining machines. Steve Nunley, Farming Operations Manager Pride Packing, Wapato, Washington "Orchard Rite Service is second to none." Orchard-Rite® Wind Machines • www.orchard-rite.com "We're real believers in the Auto Start option." Steve Nunley "Many times, fruit in dry climates retains residues longer than fruit in wet climates." —Dr. Mark Whalon