Issue link: http://read.dmtmag.com/i/114539
photos courtesy of chang-lin xiao At right, sphaeropsis cankers on a crab apple tree trunk. Rainier When it comes to cherry trees, we've got the top picks. From the early Coral Champagne variety with its flavorful, deep red-wine fruit, to the Rainier, which produces delicate, golden gems, ProTree Nurseries has the cherry varieties and rootstocks that you are looking for. Call us today to place your order for delivery from the following tree varieties: ® Benton™ Brooks™ ® ™ ™ ® Crab apple trees infected with sphaeropsis have twig dieback. ® ™ Dr. Mike Willett, vice president for scientific affairs at the Northwest Horticultural Council, who is a principal investigator for the new pruning project, said the ultimate goal is to find a practical way to satisfy the concerns of the Chinese authorities. Typically, crab apples are minimally managed after an orchard is planted. Chinese quarantine officials have suggested that field control and management of pollinizers in winter is important to reduce infection the following season. However, no research has been done yet to confirm that pruning crab apple trees to remove sources of the pathogens is an effective control for these diseases, Kim told the Research Commission. Willett said they hope to find out if pruning heavily infected crab apples does enough to address the problem. He noted that in most orchards the fruit trees don't show disease symptoms even when the crab apples do. Asked if the research would generate answers quickly enough, Willett said he had no idea whether what they would propose to the Chinese would solve the problem in time for market access for the 2013 crop. "But, obviously, that's the goal," he said. www.goodfruit.com The pruning project will focus on two commercial Red Delicious orchards, one of which has alternate rows of Manchurian crab apples as well as every fourth tree in the commercial rows. In that orchard, all the crab apples are covered with sphaeropsis or speck rot, Kim said. Tom Auvil, research associate with the Washington Tree Fruit Research Commission, who is also working on the three-year project, will supervise the following pruning treatments on the crab apples: —Chainsaw pruning before bloom to keep the pollinizers in their space so they don't intermingle with the commercial fruit trees —Chainsaw pruning plus detailed pruning before bloom to remove infected twigs and branches —No pruning, as a control Kim will monitor fruit infections on commercial trees near the crab apples throughout the growing season. Some fruit will also be stored for up to nine months to monitor development of the diseases. • ™ ™ ™ ® , Krymsk®, *Not all varieties are available on all rootstocks. Call for specific grafting information. 741 Sunset Road, Brentwood, CA 94513 800.634.1671 (Alison Clegg or Richard Chavez) 877.457.6901 (Henry Sanguinetti) Fax 925.634.6040 GOOD FRUIT GROWER March 15, 2013 25