Voracious Western Grapeleaf Skeletonizer moth discovered in Napa County vineyard

NAPA (CBS SF/BCN) -- Living up to its name, the discovery of a voracious Western grapeleaf skeletonizer moth in a Napa County vineyard has growers and agricultural officials on edge.

The moth can cause extensive damage to grape leaves, often resulting in partial or complete defoliation of grapevines. The feeding can also damage fruit and lead to secondary fungal damage.

"We do not want this pest to become established in Napa County," said Tracy Cleveland, county agricultural commissioner.

 The insect trapper, Jesse Guidi, had been monitoring the presence of another pest in Pope Valley, the glassy-winged sharpshooter, when he encountered the skeletonizer on May 12.

 The commissioner has ordered that 25 additional traps be employed within a mile radius of Guidi's discovery.

According to the county, the skeletonizer is not native to the area and was last seen in the Napa region in 2018. The pest first arrived in California from Arizona or New Mexico in the 1940s.

Authorities say evidence of the moth's presence is fairly easy to spot, as it leaves only a leaf's veins behind, producing a distinctively lacy appearance.

The skeletonizer also likes Boston Ivy and Virginia Creeper. In its larval stage it displays colored bands around its body.

 Cleveland was asking Napa County residents that suspect they have found a Western grapeleaf skeletonizer caterpillar or adult moth to bring it to the county office "immediately" or contact them in order to help identify it.

 Growers, vineyard managers, wineries and residents are asked to inspect any farm equipment being transported into the county to ensure that they are free of the pest, as well.