Issue link: https://read.dmtmag.com/i/635697
www.goodfruit.com Good Fruit Grower FEBRUARY 15, 2016 11 labor cost he would rather pay than continually fix flats. But some growers didn't prune them at all. The unkempt condition led to dead and decaying branches that gave the opportunistic fungi a place to fester. The rots affect commercial cultivars of apple trees, too, but growers had always pruned those as part of their orchard management and kept the diseases at bay without even realizing it. In 2012 on shipments of U.S. apples, Chinese fruit inspectors found three rots — speck, sphaeropsis and a third kind called bull's-eye rot (Neofabraea peren- nans) — previously unseen in their country. They shut down imports for two years. U.S. officials suspected some politics behind the move but began studies to set the record straight nonetheless, said Mike Willett, manager of the Washington State Tree Fruit Research Commission. Though they had conducted no trials, researchers in Washington already knew that pruning and postharvest fungicide reduce the incidence of speck and sphaeropsis, Willett said. The existing work, plus the new tests by Sikdar, helped convince China to reopen the market in November 2014. Today, pruning is mandatory for growers planning to ship to China, Willett said. "They need to know if they're going to export fruit to China, they have to prune the crabs. It's not optional." The risk is high. Speck and sphaeropsis rot have been known to cause orchard losses of up to 24 percent in isolated blocks. The pathogens spread by rain and irrigation water splashing from infected dead twigs and fruit mummies left to overwinter as pycnidia on those underpruned Manchurians. Making matters worse, growers won't see the rot in the orchards. The symptoms don't show up until after at least 60 days in cold storage and usually not until 90 or more. Through May this year, Sikdar will be comparing the incidence of speck and sphaeropsis rot on three catego- ries of apples — those picked from orchards with pruned Manchurians and treated by fungicide, those from pruned orchards without fungicide and a control group of apples with neither method. So far, pruning is better than noth- ing but pruning plus fungicide works the best, she said. In the future, Sikdar will study the biology of bull's-eye rot, another postharvest fungal infection, and possible TJ MULLINAX/GOOD FRUIT GROWER Dr. Parama Sikdar, left, inspects Red Delicious apples for evidence of rot in a cold storage facility in Wenatchee, Washington, with Emmi Klarer. Sikdar, a plant pathologist for the WSU Tree Fruit Research and Extension Center, is looking for evidence of rots from the postharvest diseases caused by Phacidiopycnis washingtonensis and Sphaeropsis pyriputrescens. © 2016, Trécé Inc., Adair, OK USA • TRECE, PHEROCON and CIDETRAK are registered trademarks of Trece, Inc., Adair, OK USA PLEASE: ALWAYS READ THE LABEL The Mating Disruption System for both MALE… and FEMALE Codling Moth, Cydia pomonella INSEC T PHEROMONE & KAIROMONE SYSTEMS INCORPORATED ® Your Edge – And Ours – Is Knowledge. Contact your local supplier and order now. Visit our website: www.trece.com or call 1- 866 -785-1313. CIDETRAK ® CMDA COMBO ™ MESO ™ mating disruption dispensers contain a unique combination of Codling Moth pheromone AND a patented male AND female behavior modifying kairomone called DA. Designed to deliver long-lasting performance with remarkably fast application for apples and pears. CIDETRAK ® CMDA COMBO ™ MESO ™ dispenser in use • What it does: The DA kairomone enhances the eect of the Codling Moth pheromone on male mating disruption. And, initiates female mating disruption through behavior changes in the female resulting in oviposition disruption, less mating, higher virginity and lower damage. • How to use it: Fast hanging design, clips easily and securely onto branches, and eliminates lateral branch scarring. • Longevity: Long-lasting performance. TRE-0842, 12/15