Over the last 10 years, Fresno County farmers have reported increasing raisin moth populations in organic raisin vineyards. Addressing this concern, Kent Daane, UC Cooperative Extension specialist in the Department of Environmental Science, Policy and Management at UC Berkeley, will update growers on the pest’s biology, management and damage at the San Joaquin Valley Grape Symposium Jan. 8 in Easton.

Daane and his research associates followed moth populations in organic and conventional fields to document this observed change and determine if there were any specific causes for increases in raisin moth densities. In a 2013 season study, UC Kearney Agricultural Research and Extension Center entomologists found that spring to early summer pheromone trap catches of raisin moths were prevalent across numerous vineyards, regardless of management practices. However, overall seasonal damage in 2013 was low.

“The primary difference between vineyard sites with or without raisin moth damage appeared to be well-timed and effective insecticide sprays,” Daane said. “One problem for organic sites may be the availability of insecticide materials that have long enough residual activity to control the larvae of adult moths entering the vineyard, and once the larvae are deep inside the grape cluster they are difficult to control.”

In addition to Daane’s report, the San Joaquin Valley Grape Symposium includes the following research updates:

• Rootstocks for raisin production by Sonet Von Zyl, Fresno State University
  
  
• Raisin production canopy management by Matthew Fidelibus, UC Cooperative Extension specialist in the Department of Viticulture and Enology at UC Davis, based at the UC Kearney Ag REC in Parlier
  
  
• Raisin grape breeding program by Craig Ledbetter, USDA Agricultural Research Service, based in Parlier
  
  
• Economics of producing raisins, by Annette Levi, Fresno State University
  
  
• Grapevine trunk diseases and grower survey

The symposium begins with registration at 7 a.m. and concludes following lunch at 1 p.m. at the C.P.D.E.S. Hall, 172 W. Jefferson Ave., Easton, Calif.

Registration is $15 in advance and includes lunch. Registration at the door is $20. To preregister, send the names of attendees and a check payable to UC Regents for $15 each to San Joaquin Valley Grape Symposium, 550 E. Shaw Ave., Suite 210-B, Fresno, CA 93710. To register with a credit card, fill out the online registration form at http://ucanr.edu/sjv2014.