Issue link: http://winesandvines.uberflip.com/i/279499
64 p r a c t i c a l w i n e r y & v i n e ya r d a p r i l 2 0 1 4 g r a p e g r o w i n g and serve as "canaries" for when asco- spore release does occur. As the canopy develops and the poten- tial for longer distance spread of the pathogen from other vineyards increases, the sampling head should be placed into the turbulent mixing layer at the top of the canopy. One might even want to move the trap, if there has been no detec- tion at the current location, to a block in your vineyard that is perennially the first to have observable disease or regions that have the most fruit damage the previous season. These locations likely have ter- rain features that cause more spores to be preferentially deposited from external inoculum sources. An example of this phenomenon is a site in the northern Willamette Valley of Oregon. A trap placed in one block was repeatedly testing positive, but no dis- ease could be found in the block despite looking at thousands of leaves. Aban- doned vines were found up wind and were likely the source of E. necator being detected in the trapping results. Since the offending inoculum source was not from the vineyards he managed, his only knowledge of the problem was from the spore detection results. The grower has significantly reduced the fruit infection in this block using the spore data to shorten spray intervals, thus managing the external inoculum source. This problem block is now a reserve block. Grower innovation During the testing of the spore trapping in Oregon, we gave growers estimates of spore concentration whenever there was a positive detection. One organic grower started using these numbers to help him decide the fungicide application interval all season. He would decrease the appli- cation interval when the spore concen- tration was increasing or extend it when the concentration was decreasing or remaining low or not detectable. Over the course of two years, he was able to save one to two additional fungicide applications. In 2013, we began exploring whether this approach was commercially feasible at six different Oregon vineyards. Paired blocks were established with each grower, where one block was maintained according to the grower 's standard pro- gram and the first fungicide application delayed for the paired block until inocu- lum detection and then the spray interval was adjusted based on the spore concen- tration. Results from 2013 in Oregon were inconclusive, since only one vineyard reached an action-threshold that altered the application interval. However, the experience of Coastal Viticultural Con- sultants indicates that this approach has value in improving disease control in California. In 2013, Oregon growers still made two fewer applications to the blocks managed based on the inoculum detec- tion data compared to their standard program with similar disease control. Since a typical fungicide application can cost $50 -$80 per acre depending on ter- rain and material sprayed, a reduction of two sprays realized by all growers in Oregon (approximately 35,000 acres) equates to saving the industry $6 million each year! Promote your wines to leading Zinfandel enthusiasts and extend your winery's relationship in the market. Join Us! We are champions of Zinfandel— America's Heritage Wine Become part of our proud legacy zinfandel.org • 530-274-4900 Zinfandel Advocates & Producers is a 501(c)(3) non-profit organization. ZAP is dedicated to advancing public knowledge of and appreciation for American Zinfandel and its unique place in our culture and history. You know how good your Zinfandel is... Toll-Free: 877.552-4828 909.451.2299 • Fax: 909.593-8309 For your nearest dealer, contact: WIREVISE® WIRELINK® Trellis & Fence Wire Anchor Embossed jaws grip the wire as it is inserted and prevent it from being pulled out. The wire is retensionable with a pair of pliers or a claw hammer. Tool-free Trellis & Fence Wire Splicer Broken or sheared ends of a wire are slipped into either end of the WireLink to make a secure splice. Requires no tools. Both WireVise and WireLink are available for wire from 9-13 gauge. Agfast_WireVise_Jan08 12/13/07 12:34 PM Understanding inoculum availability is the future of disease management.