Good Fruit Grower

September 2012

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Pears Cooperative effort defeats pests A n areawide effort to control codling moth without organophos- phate chemicals has resulted in better control of both codling moth and pear psylla as well as lower pesticide costs for a group of pear growers in Hood River, Oregon. Many of them are no longer applying pesticides for either Costs have declined along with pest populations. by Geraldine Warner pest during the growing season. The project was launched in 2007 with a U.S. Environmental Protection Agency grant and has been managed by the Columbia Gorge Fruit Growers Association working with Oregon State University faculty. It started out with 11 growers on more than 600 acres in the Dee Flat area of Hood River. Two years later, another 13 growers with 650 acres of pears in nearby Odell joined the project. Growers are expected to apply a full label rate of pheromone dispensers on all their apples and pears, and to use alterna- tives to azinphos-methyl or phosmet if supplemental sprays are needed. Treatment decisions are based on codling moth monitoring using one trap for each three to five acres—a higher number of traps than previously used. Growers have been meeting with pest control advisors, OSU faculty, and Columbia Gorge Fruit Growers Association staff to review monitor- ing results and population trends, and to learn about the biology of the pest and the treatment options. They also meet after harvest to review the results. Piecemeal Previously, many of the growers had used mating disruption and softer pesticides for codling moth control, but the pheromone dispensers had often been applied at lower than recommended rates and applied in a piecemeal manner, said Dr. Steve Castag- noli, OSU extension agent in Hood River. While this addressed concerns about the environmental and human risks of pesticides, growers had varying levels of success in managing codling moth. Barriers to long-term adoption of alternative codling moth management strategies include the high cost of pheromone dispensers, which is about $120 per acre, and the perception that more fruit will be damaged, Castagnoli said. The EPA Strategic Agricultural Initiative grant, which was designed to help growers tran- sition away from pest management pro- grams relying on organo phosphates, provided a subsidy to growers of about $30 per acre for the first three years. Grant funds were also used to pay wages and mileage for a field technician who checked the codling moth traps weekly and evaluated fruit for damage after har- vest. Erick Von Lubken, a grower at Dee Flat, said codling moth was a serious concern before the project began, and some grow- ers were applying as many as four cover sprays. Now they're applying none. Sprays are used for pear psylla at the dormant through bloom stage, but no summer sprays are needed because the absence of organophosphate cover sprays allows natural enemies to control psylla. Grower Steve Hunt, who joined the project in 2007, had been using phero - mones on his 50 acres of pears since 2000, but it was not effective because of the small area treated. Mated moths are able to move in from neighboring blocks. The areawide approach is the key to making it work, he said. SOFT SPRAY PROGRAMfor pears T hough a no-organophosphate codling moth control program is more expensive at first, it's not long before growers are saving money, says Bruce Kiyokawa, a pest control advisor with Chamberlin Dis- tributing Company in Hood River, Oregon. Kiyokawa works with several pear growers who are participating in an areawide codling moth program in Hood River. The first year of using mating disruption makes pest control more expensive, but the sec- ond year it's a wash, he says, because growers are not applying as many pesticides. By year three, they start saving money. "I think probably the impact of not spraying is getting to be larger now, with the price of labor and fuel," he said. "It's probably saving two to three trips with sprayers going through the orchard by doing this." Most growers in the program are using a full rate of NoMate or Isomate pheromone dispensers (400 dispensers per acre). After that, they do nothing unless trap catches exceed the treatment threshold. If a spray is needed dur- ing the growing season, most are using Altacor (rynaxypyr), which Kiyokawa says appears to be effective against codling moth without being disruptive to beneficial insects. Last season was the sixth year of the project for half the growers and the fourth year for the rest. He estimates that no more than 15 percent of the growers applied Altacor and none applied it more than once. Pear psylla Growers report that control of their other key pest, pear psylla, has Pear psylla early instar nymph and larvae. improved since the areawide program began. Kiyokawa said growers have an aggressive control program up to bloom time, but are cautious about applying pesticides after that stage. They typically apply oil and sulfur at the delayed-dormant stage and an adulticide, such as endosulfan, to catch the psylla returning to the orchard after the winter. After endosulfan is phased out next year, they will be left with the option of using Nexter (pyridaben). Few growers in the area use kaolin clay for psylla control. "Then, for the most part, we're just playing a waiting game to see if psylla come up," Kiyokawa said. "If they don't, we do nothing. If they do, we may come in with Ultor." Ultor (spirotetramat) also appears to be quite selective and not harmful to natural enemies, he said. Perhaps half the growers have been using this prod- uct. The option to use Altacor or Ultor when needed has been the key to help- Hardshell pear psylla. ing growers transition to the softer program, he added. "Otherwise, we would be in big trouble trying to go soft off the bat. I think Ultor will always be some- what of an important tool because I don't think we're always going to see low pear psylla populations. I think they go in cycles." —G. Warner GOOD FRUIT GROWER SEPTEMBER 2012 23 Steve Hunt Erick Von Lubken

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