Issue link: http://read.dmtmag.com/i/386317
A new project will focus on controlling decay and fi nding pollinizers that are not disease hosts. by Geraldine Warner T he Northwest Horticultural Council and the Washington Apple Commission have secured a federal grant of more than $1.9 million to fund research needed to secure access to the Chinese market. Washington apple producers have been shut out of China for the past two seasons because of concerns about fruit infected with three types of decay: bull's eye rot (Neofabraea perennans), speck rot (Phacidiopycnis washingtonensis), and sphaeropsis rot (Sphaeropsis pyriputrescens). The industry has lost more than $30 million in sales so far. This year, Chinese offi cials agreed to reopen the mar- ket under a new, more stringent export protocol that requires growers take steps to manage the fungal dis- eases in the orchard and certify they have done so. About a decade ago, Dr. Chang-Lin Xiao, then pathol- ogist at Washington State University, discovered that some fruit decay had been misidentifi ed and was actu- ally caused by two organisms not previously known to cause decay in apples: P. washingtonensis and S. pyri- putrescens. He also found that Manchurian crab apple, commonly used in orchards as a pollinizer, was host of the organisms and acted as a source of inoculum that spread to neighboring commercial fruit trees. Xiao recommended pruning dead limbs and diseased fruit out of the crab apple trees to reduce the risk of infec- tion in the orchard. Dr. Mike Willett, vice president for scientifi c affairs at the Hort Council and author of the funding proposal, said many growers had stopped pruning Manchurian crab, which was a logical decision as the wood has sharp thorns that, when dropped on the orchard fl oor, can damage the tires of orchard vehicles. However, it has resulted in increased fruit decay in some orchards with Manchurian crab pollinizers. Systems approach Offi cials of the two countries agreed during bilateral negotiations last November in Xiamen, China, that, as a condition of reopening the market, the United States would conduct research to validate the systems approach proposed by the United States to mitigate decay. The sys- tems approach involves removing cankers and twigs with dieback symptoms on crab apple trees, applying post- harvest fungicides, and inspecting fruit at the packing house to ensure that no decayed fruit arrives in China. Part of the federal grant, which was awarded by the Technical Assistance for Specialty Crops program, will fund this research. It will also fund research into alterna- tive pollinizers as a longer-term solution to eliminating decay in exported apples. As neither WSU nor Oregon State University has a 10 OCTOBER 2014 GOOD FRUIT GROWER www.goodfruit.com Research tackles decay issue Dr. Richard Kim, right, shows how unmanaged Manchurian crab apples can spread postharvest storage diseases during a crab apple workshop near Quincy, Washington, earlier this year. PHOTO BY TJ MULLINAX PLAY goodfruit.com/media Scan to learn about Manchurian crab apple management.