California's Department of Food and Agriculture says it is expanding efforts to curb the spread of a new grape pest.

The European grapevine moth first appeared in the United States in September in the Oakville area of Napa County. CDFA said surveys and trapping since then have turned up two infestation zones, one on the eastern side of the city of Napa, the other in an area between Oakville, Rutherford and St. Helena.

The moth is blamed for damage to several vineyards in the area. CDFA has erected a quarantine encompassing 162 square miles in parts of Napa, Sonoma and Solano counties.

The moth feeds on other crops, but does most of its damage to grapes. It is found in southern Asia, Europe, North Africa, Anatolia, the Caucasus and South America.

It overwinters in pupa stage, making it difficult to detect until spring conditions arrive. Its first-generation larvae feed on flowers, causing damage that can impact yields, then pupate inside a webbing spun around flowers or under leaves. Second-generation larvae feed on grape clusters before pupating inside the fruit.

The third larval generation causes the most damage, feeding on ripening grapes and causing fungal damage and rotting.

CDFA said it is setting traps statewide to track down any further infestations. The strategy involves starting in warmer southern reaches of the state and progressing northward as spring arrives.

The agency said it is planning public events to brief growers on quarantine regulations.

-- Wes Sander

Link

For more information and a map of the quarantine zones go to:

www.cdfa.ca.gov/PHPPS/PE/InteriorExclusion/egvm_quarantine.html