Issue link: http://winesandvines.uberflip.com/i/279499
62 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 iticulture MEMBERS SAVE! Member registration fees ar 65th ASEV National Conference & 39th ASEV Eastern Section Annual Meeting June 23–27, 2014 | Hyatt Regency Austin | Austin, Texas USA S p E c i A l E V E n T S • Merit Award Presentation — Dr. Linda Bisson, nia, Davis • Texas W d Tour • Enhancing W • Winemaking for Challenging Environments • Research Reports • Easter ines of the East" Reception Visit our website for updates on the 2014 program. www.asev.org l 530-753-3142 65 n a t i o n a l c o n f e r e n c e s i x t y f i f t h s c i e n c e a p l a t f o r m f o r p r o g r e s s factors that impact spore formation and dispersion in order to efficiently manage plant diseases. Our current research on spore dispersion shows that wider tractor rows cause more spores to be lost to deposition onto the vineyard floor. This indicates that wider spaced vineyards have less risk to disease development that tightly spaced vineyards under the same conditions. The California results further indi- cate that monitoring of inoculum avail- ability may be useful in improving disease management of grape powdery mildew. What does a trap represent? The short answer is we do not know. It could be a single vine or hundreds of acres, and it literally depends on which way the wind is blowing and how fast. The size and origin of the air mass transporting the spores will change with wind speed and direction. This air mass interacts with terrain features and canopy architecture (vine-row spacing, height and training system) to cause air turbu- lence. This turbulence is responsible for the number of spores in the air mass moving over the trap since it drives spore release, deposition and how high the Figure 3: Modeled spread of grape powdery mildew in a vineyard with 9-foot-wide tractor rows and leaf area index of 3. Blue dots are mildew spores released from the top of the canopy, and red dots are spores released from the fruit zone. Upper and lower images show the effects of 5 mph wind coming from the southwest and west, respectively. More spores are transported into the air when air movement is not perpendicular or parallel to the vine row.