California and federal agricultural officials will lift the European grapevine moth (EGVM) quarantine in Fresno, Mendocino, Merced, and San Joaquin counties effective March 8.

U.S. Agriculture Secretary Tom Vilsack announced $8 million in federal funding to continue the program’s progress. Grower vigilance and local support have combined with regulatory oversight to achieve a substantial reduction in the area affected by the grapevine pest.

“The announcement of funding from our federal partners at USDA is welcome news for California grape growers and their consumers,” said Karen Ross, Secretary, California Department of Food and Agriculture (CDFA). 

“We have made significant progress toward reducing the quarantined areas with the help of residents, growers, and local officials. We have a lot of work still to do and the federal funding announced by USDA Secretary Vilsack ensures we can sustain our momentum toward eradicating the pest in the remaining counties,” Ross said.

“This program is a model of how industry and government officials can coordinate detection, treatment and regulatory action to deal with a serious agriculture pest,” said USDA Deputy Undersecretary Rebecca Blue. “The cooperating agencies and industry achievements to date encourage us all to complete the task of eradication of European grapevine moth in California.”

The lifting of the quarantines in the four counties will take effect March 8. The quarantine continues in the original infested area encompassing portions of Napa, Sonoma, and Solano counties. 

More isolated infestations have also triggered smaller quarantines in Nevada, Santa Clara, and Santa Cruz counties.

The areas that remain under quarantine have also been reduced by a change in the regulation that originally required the inclusion of a five-mile "buffer" around any site where the pest had been detected. Continual monitoring of the infestations and assessment of the biology of the insect has led officials to reduce the buffer requirement to three miles.

Approximately 661,110 acres are being released from the quarantine. The remaining quarantine areas cover a total of approximately 1300 square miles, down from 2,335. 

Maps of the quarantine and related information may be found online at:
http://www.cdfa.ca.gov/phpps/PE/InteriorExclusion/egvm_quarantine.html and http://www.aphis.usda.gov/plant_health/plant_pest_info/eg_moth/index.shtml.

The quarantines primarily affect farmers as well as those who harvest, transport, and otherwise process or handle grapes and other crops. These growers and business people sign compliance agreements that indicate how crops, vehicles, equipment, and related articles are to be handled and tracked during the quarantine.

Residents are also affected by the quarantine. Agricultural officials generally work with residents to remove grapes and flowers from their homegrown grapevines. For those who prefer to harvest the grapes, the vines may be treated with the organic-approved pesticide Bt.

EGVM, Lobesia botrana, is found in southern Asia, Japan, Europe, North Africa, Anatolia, the Caucasus, and in South America.

The pest primarily damages grapes, but has also been known to feed on other crops and plants.
The EGVM larvae, not the adult moths, are responsible for the damage to grapes. Larvae that emerge early in the spring feed on grape bud clusters or flowers and spin webbing around them before pupating inside the web or under a rolled leaf. 

If heavy flower damage occurs during this first generation, the affected flowers will fail to develop and yield will be reduced. Second-generation larvae enter the grapes to feed before pupating in the clusters or in leaves.

Larvae of the third generation - the most damaging - feed on multiple ripening grapes and expose them to further damage from fungal development and rot. These larvae overwinter as pupae in protected areas such as under bark, and emerge as adults the following spring.