Home Winemakers and the European Grapevine Moth
Working Together We Can Stop Its Spread
Attention home winemakers. There’s a new bug around, and it’s one that you don’t want hitching a ride on the grapes you use for winemaking.
The European Grapevine Moth (EGVM) is a new and serious threat to California. Discovered in Napa in 2009, it has already spread to several winegrape growing regions of California. It has traveled great distances, farther than it normally would fly, by hitchhiking on grapes, farm equipment, and even on wooden posts.
Any grapes leaving an EGVM-infested area must meet certain requirements covered in a document called a compliance agreement. Check with your local county agricultural commissioner as well as the county you plan to obtain your grapes from for the latest quarantine information. You may be required to complete and follow a compliance agreement to help ensure you do not spread the EGVM. There is no cost for the agreement, and it is available on county ag department websites.
Some aspects of the compliance agreement involve the following:
Only transport grapes in tightly-covered bins, or other covered containers, to prevent any moths or larvae from escaping or falling out during transport. In some areas, bins that are ‘slack filled’ are acceptable for transport.
Home winemakers must ensure that all equipment (bins, barrels, machinery, gondolas, etc.) used for the harvest or transport of bulk grapes is thoroughly cleaned of all host material, debris, and all life stages of EGVM after every use.
Be aware that live EGVM can be present in grape must and pomace. (Grape must is the juice, skins, seeds, pulp, and stems from freshly-crushed grapes.)
Two methods are effective for killing all life stages of the EGVM during the winemaking process:
Pressing grapes and other materials a minimum of two bars of pressure. If your winemaking technique calls for pressing less than two bars of pressure, then after you have pressed your grapes and removed the juice, continue to press the grapes to two bars or more, discarding the juice from that additional pressing.
Fermentation with the must and pomace, which includes skin, pulp, seeds, and stems.
Proper Handling of All Plant Materials is Key to Stopping the EGVM
All material other than grapes (including green waste, leaves, stems, culls, leaf litter, and other unprocessed or uncrushed material) must be handled in a manner that kills all life stages of the EGVM. Methods include:
Processed, handled, or treated in a manner approved to eliminate live life stages of the EGVM and then moved directly to a city or county sanitary landfill or state-licensed compost facility within the EGVM quarantine area.
Disposed of in an approved green waste container prior to being transported to an approved facility.
Transported by an approved green waste hauler to an approved green waste receiver.
DO NOT use home composting as it does not eliminate all life stages of the EGVM.
If you are buying only grape juice from a supplier, you are not at risk of transporting the EGVM.
Grape growers have made significant progress in reducing populations of the EGVM. With your help, we have a good chance of eradicating the EGVM from California.
Help keep your neighborhood EGVM-free.
Do Your Part and Help Protect California from the European Grapevine Moth
More information about EGVM is available online at:
CDFA Pest Hotline 1-800-491-1899