By The Grower staff

Three European grapvine moths have been trapped in Fresno County, making it the fifth county in California in which the invasive pest has been discovered.

The moth was trapped initially in Napa County in September 2009. Since then, it has been found in Sonoma, Medocino and Solano counties.

Two moths were picked up in traps about a half mile apart in traps that were placed in vineyards southeast of the city of Fresno, according to a news release from the Fresno County Ag Commissioner's office.

A third moth was picked up in a trap two days earlier near Kingsburg, about 11 miles from the other two sites.

As a result of the finds, additional traps have been placed in about an 80-square-mile area.

The ag commissioner's office and the California Department of Food and Agriculture currently have more than 5,000 grapevine moth traps in the county.

The larvae damage grape in two ways.

First, their direct feeding damages the grape berries.

The feeding sites also provide entry ways for diseases, such as Botrytis or gray mold.

Damage is most severe in grape varieties with tight clusters.

As its name implies, European grapevine moth is a pest of Europe, as well as Japan, the Middle East and southern Russia. More recently, it has become a pest of Chile.