Good Fruit Grower

May 15

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Photo by Peter shearer, osu the tree before laying eggs, giving the grower a good chance of killing them before they reproduce. When spotted wing drosophila first moved into Washington, it was clear that some control failures were due to growers using the cherry fruit fly attract-and-kill product GF120 and nothing else, Beers said. While the pesticide in the product, Entrust, has done a good job of controlling spotted wing drosophila, GF120 allowed a fair amount of damage. A female spotted wing drosophila lays eggs on a cherry. "We warned growers, 'Don't rely on this technology for spotted wing drosophila," and that's still our recommendation," she said. "But I heard a lot of grumbling about how great the technology was, how useful it was, and how easy and fast it was to apply, and thought it was worth a second look, to go back and see if we could retool it a little bit." GF120 consists of a bait combined with Entrust. It is typically applied to trees from a four-wheel vehicle in very small amounts. Cherry fruit fly that are attracted "Some of the responses we got were, 'It worked the year before.' " —Peter Shearer Nut ri- Cal Effects of Using Nutri-Cal with Nutri-K on Cherries Effec Effe cts ffec Nutr Cal ri% MARKETABLE GRADES OF BING CHERRIES 80 70 Nutri-Cal 36% Increase in Premium Grade 8.5-9! 80 BRIX QUALITY OF BING CHERRIES 25 21.25% 20 17.00% 56.7 60 50 44.2 15 40 10 30 20 20 5 10 0 PREMIUM MEDIUM 0 Application Rate of 2 Quarts Nutri-Cal & 1 Quart Nutri-K Applied 6 times beginning at Petal Fall 2011 Application Dates: May 23, May 27, June 3, June 11, June 19, June 24 Ron Britt & Associates, Yakima, WA 2012 Residual effect FIRMNESS EVALUATION OF BING CHERRIES % PREMIUM COLORS OF BING CHERRIES 370 100 369.50 g 369 367 95.75 95 368 90 366.28 g 89.25 85 366 80 365 364 GRAMS FORCE TO SQUEEZE SKIN 1mm 75 COMBINED MAHOGANY & DARK MAHOGANY Make Sure You Always Ask For ® ® C.S.I. CHEMICAL CORP. 800-247-2480 22 May 15, 2013 GOOD FRUIT GROWER PACIFIC NORTHWEST Walt Grigg: 509-952-7558 10980 Hubbell Ave., Bondurant, Iowa 50035 to the bait and come into contact with the pesticide, die. As a possibility for spotted wing drosophila, Beers has been testing Monterey Ag Bait (which she found to be an effective bait in traps) combined with the same toxicant, Entrust. She modified the sprayer to have six nozzles instead of two and aimed them at the upper, middle, and lower parts of the canopy, in an effort to increase the number of droplets in the orchard. She used six gallons per acre of the combined product, whereas the maximum allowed rate for GF120 is less than a gallon. Like Shearer, she took treated leaves and fruit back to the laboratory where flies were exposed to them. The new bait combination gave similar control to Entrust, which Beers said was encouraging. While it might never become a stand-alone treatment, it could be a supplement, she said. The residual effect of pesticides is a key issue because growers have to balance the need to control the pest while meeting maximum residue levels for exported cherries. Materials with the shorter preharvest intervals, such as Sevin and Malathion, had the shortest effective periods. Warrior and the organophosphate Diazinon have the longest residual effects but also longer preharvest intervals. Beers also urged growers to think about resistance management and avoid repeated use of the same products. "The first two years, we were in emergency mode, and the most important thing to do was to control this pest," she said. "We've had a couple of years now, and it's become clear that some materials are popular because of their low MRLs, and it's going to be easy to overuse them. It's time to start thinking about resistance management and developing programs that will help prevent it." •

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