Issue link: https://read.dmtmag.com/i/71703
of viruses, of which tomato ring spot virus is the greatest concern. Ecto-parasitic nematodes also include ring nema- todes, so called because of the annules around their bodies. Ring nematodes were overlooked in the Okanagan Valley until around 2004 because it takes a different soil extraction method to detect ring nema- todes than scientists were using, Forge said. "When we switched to a different extraction method to intentionally look for ring nematodes, we started finding them in many different vineyards." Ring nematodes are not a concern in apples, but have long been associated with problems in stone fruits, and particularly with peach tree short life, a disease complex that involves winter injury, pseudomonas canker, and cytospora canker, as well as nematodes. "Nematodes are always associated with this kind of downward spiral as well," Forge said. About a decade ago, studies were done in Califor- A lesion nematode buried in root tissue. nia on potted peach trees in the field to assess the effect of ring nematodes on the trees' susceptibility to pseudomonas canker. Some trees were planted in soil with ring nematodes and some without. The trees were then inoculated with the pseudomonas pathogen. The effects of treatments with calcium, indoleacetic acid, or urea were also tested. On trees planted in soil with nematodes, pseudomonas and cytospora cankers grew at a much faster rate than on trees planted in soil without nematodes. "These nematodes can cause growth suppression by themselves in the absence of other pathogens when they're in high numbers," Forge said. "But this gives us another level of understanding of their potential role in orchard dynamics." This kind of interaction has been observed in peach, prune, almond, and peach, but there is no data for cherries. Forge said he hopes to do research in the future to bring more clarity to the role ring nematodes might have in cherry orchard issues. Management In British Columbia, short-term nematode control strategies include preplant fumi- gation with Vapam (sodium methyldithiocarbamate) or a postplant nematicide applica- tion of Vydate (oxamyl) on nonbearing trees. Short-term cultural or biological controls include using nematicidal cover crops, such as marigolds, green manure cover crops, or biofumigants. Marigolds are among plants that are antagonistic to nematodes because of com- pounds they emit. However, Forge said planting a marigold rotation cover crop before establishing the orchard is not practical because the flowers are difficult to grow economically, and it means that the land is out of production for a year. Experiments have been done in other crops with cover crops of Saia oats and Wheeler rye, which look promising. Dr. Mark Mazzola, plant pathologist with the U.S. Depart- ment of Agriculture in Wenatchee, Washington, has been researching green manure Brassica cover crops, such as canola, rape, and mustards, as well as using a Brassica seed meal as a planting hole amendment. As the tissues of these plants break down, they give off compounds that are toxic to nematodes. But Forge said results with Brassicacover crops have been hit and miss. Some Brassica species are hosts of nematodes, so the plants must be incorporated into the soil to get the green manure effect. To be effective, there must be sufficient biomass, and it needs to be incorporated into the soil at the right time. Mycorrhizae can deter nematodes from attacking plant roots, but that effect has only been observed in fumigated soil, Forge said. Mycorrhizae are present in the soil, and a preplant treatment with mycorrhizae may or may not be beneficial, depending on how degraded the soil is and whether it has been fumigated. Forge said he sees great potential for long-term management of nematodes, rather than short-term controls. This would involve identifying cultural practices that prevent the build-up of nematodes to damaging levels, even though there will always be some nematodes. Long-term strategies will involve focusing on soil health, which boils down to optimizing conditions for root growth and perhaps fostering the build-up of natural enemies of nematodes, which might minimize the build-up of nematode populations. Ultimately, the development of nematode-resistant and tolerant rootstocks also needs to be considered more seriously. "It's time to consider alternatives to fumigation," he said, noting that fumigants are broad-spectrum biocides that have negative impacts on soil health and the environment and are likely to be subject to increasing restrictions. Composts and organic mulches can help suppress some plant diseases caused by fungi. For a number of years, Forge has been studying how they might also suppress nematodes on perennial crops under field conditions. Although he's not seen much nematode suppression, he has seen improvements in root growth. "Regardless of whether you have nematode issues or not, composts are generally good for enhancing root growth and improving soil health," he said. • www.goodfruit.com Apple Orchard Systems...................................................................................$25 Edited by Bruce H. Barritt. This special issue of Compact Fruit Tree is available to the public and features presentations made at the International Fruit Tree Association workshop on Apple Orchard Systems. The team of presenters included Dr. Stuart Tustin from New Zealand; Kurt Werth from Italy; Dr. Terence Robinson, Steve Hoying, and Alison DeMarree from New York; and Dr. Bruce Barritt from Washington. Cover Cropping for Vineyards.......................................................................$20 This guide fea tures cutting-edge methods for using cover crops to enhance vineyard perfor mance. Based on extensive research, it details technical and theoret ical information on how cover crops affect vineyards and promote eco logical stability. It also is a great source of infor ma tion about which cover crop is right for your situation. With how-to instruc tions for activities such as field applica tion, this practical reference is a must-have for vineyard owners, managers, consultants, and pest control advisors. Growing Grapes in Eastern Washington .....................................................$17 WSU Shortcourse on establishing a vineyard and producing grapes. High Density Sweet Cherries .........................................................................$25 International Tree Fruit Association Special Edition, June 2005. This special issue of Compact Fruit Tree showcases presenta tions made at the (IFTA) work shop on High Density Sweet Cherries, Feb. 10-12, 2005. The Next Agricultural Revolution.................................................................$15 Edited by Dr. Kent Mullinix and published by Good Fruit Grower, this book will be a valuable reference. A must-read for anyone in agriculture who expects to compete in the next decade, The Next Agricul tural Revolution is the product of a futuristic shortcourse on the Family Farm in Washington State. Orchard Pest Management (Reg. $35.00) ............................................................$20 Edited by Elizabeth Beers, Jay Brunner, Mike Willett, and Geraldine Warner. 191 full-color photos, 100 illustrations. A compre hen sive tree fruit pest identification and management reference tool. Orchard Pest Monitoring Guide for Pears ..................................................$12 Written by Philip C. VanBuskirk, Richard J. Hilton, Naná Simone, and Ted Alway. A companion book to Orchard Pest Management, this publication includes the latest techniques and is a must for Pacific Northwest pear producers. Orchard Pest Monitoring/Spanish language edition ..............................................$8 Organic Apple Production ..............................................................................$18 Published by the University of California. Over 20 years of research have culminated in the first production manual from UC for current or potential producers of certified organic apples. This manual rep resents a descriptive inventory of the methods legally available for organic apple production in California. Pear Insect Field Guide ....................................................................................$11 Compiled and edited by Michael Bush, Bradley Higbee, Brooke Peterson, Naná Simone, and Patrick Weddle. Designed as a pocket field guide for use in the orchard to help growers and con sul tants identify the common insects, mites, and spiders found in pear orchards. Pear Production and Handling Manual ........................................................$25 This manual is designed to provide a basic understanding of growth and fruit development, as well as practical consider ations on pear culture. While written with California Bartlett production in mind, pear growers of all varieties world wide will find the information useful. Text includes cover orchard and tree management; varieties, propagation, and rootstock selection; training, pruning, and orchard floor management; irrigation systems, scheduling; frost protection; nutrition; pest management; fruit harvesting, storage, and handling. Quick Identification Guide to Apple Postharvest Defects ......................$25 Tree Fruit Research & Extension Center. Compiled and edited by Wendy E. Jones and Jay Brunner, Dept. of Entomology; Eugene Kupferman, Dept. of Horticulture; Chang-Lin Xiao, Dept. of Pathology. This handy card set is available as an easy reference for apple packing house quality control workers. It will help to identify the most common defects and disorders encountered both before and after storage. Cards have a protective plastic surface and fan-out around a sturdy aluminum corner post with convenient hanger loop. Tree Fruit Pest Identification Cards ..............................................................$15 Published by the University of California. These pocket-sized laminated cards are easy to carry in the field as handy refer ences for identifying and monitoring major insect and mite pests and several important diseases in California deciduous tree fruits and nuts. Each pest is identified by a description and close-up photo graphs of important life stages. The infor mation on these 32 cards will help pest control advisors and growers know how and when to look for these pests in both growing and dormant seasons. WSU Shortcourse Three-Book Set ..............................................................$15 Tree Fruit Irrigation, Tree Fruit Physiology, and Tree Fruit Nutrition. SHIPPING: $3.50 for first book–inside U.S.A. Add $2 for each additional book. Canadian customers, please add GST. Plus additional taxes where applicable. Canadian and other foreign customers, please call or e-mail for shipping information. ORDER FROM: Good Fruit Grower, 105 S. 18th St., Suite 217, Yakima, WA 98901-2177, or call toll-free 1-800-487-9946 (local number 509-853-3520); fax 509-853-3521. ON-LINE ORDERING: www.goodfruit.com / getit@goodfruit.com Prices do not include shipping/handling and applicable taxes Order online: www.goodfruit.com GOOD FRUIT GROWER JULY 2012 35 Photo courtesy of dan wixted, university of wisconsin