It has been about one month since Solano grape growers meet with our Agricultural Commissioner to understand the presence and threat of the European Grapevine Moth. There has been a lot activity since that meeting.
Additional finds in Mendocino, Fresno, Merced and Monterey Counties has clearly signaled the pest has found it’s way into a large area of Northern CA. Most of these trappings were limited with exception of Mendocino. In Suisun Valley additional moths have been found in traps along upper Suisun Valley Road and Mankas Corner Road.
The International Technical Working Group has developed quarantine protocols that we will be detailed about in upcoming grower meetings with our Ag Commissioner. The below are draft protocols that have been recommended.
1. Nursery stock: For grape nursery stock produced within the regulated zone: (1) vines shall be kept free of flowers and berries (this is especially critical if vines are shipped in potting medium rather than bare root); (2) rootstock and scion wood cuttings, as well as dormant rootings and bench-grafted vines, shall be treated with a hot water dip (5 minutes at 127ºF). If nursery stock is to be shipped outside the regulated area, it should also be inspected and found to be free of Lobesia prior to shipment.
2. Grapes for crushing: Moving grapes from even very lightly infested vineyards (with no apparent population) into uninfested areas for crushing can start infestations that then spread into surrounding areas.
If grapes are to be moved out of regulated areas:
• Vineyards in the regulated area must be inspected and found to be free of EGVM prior to harvest.
• Trucks or containers holding grapes must be covered.
• All containers and truck bodies will be thoroughly cleaned at the processing facility.
• Loads from the quarantine area shall be given priority at the processing facility.
• All equipment leaving fields from within the infested area shall be cleaned before, during and after the harvest.
• All winery waste and unfermented pomace must be disposed of in a manner that prevents survival of any life stages of EGVM. Acceptable disposal methods i nclude approved composting on site, chipped, ground or shredded, held in approved containers prior to shipment to an approved facility by an approved hauler or treated in another approved manner such as heat. Material that has been fermented is exempt.
The TWG is optimistic based on experience in Chile that if growers judiciously follow recommendations regarding application of control measures in their vineyards, populations will be reduced to the point where disruption of normal harvesting and grape processing operations will be minimal.
