Poisonous, invasive black skeletonizer moth discovered in California vineyard

As larva, their long tufts of poisonous black spines sting and irritate the skin, covering farmers' hands in angry red welts. And if there's enough of them, they'll completely defoliate vines, induce grape rot, and leave nothing behind except a "necrotic," skeletonized leaf just as their name implies. And now, they're here in California's Napa County vineyards.

CBS Bay Area reported that insect trapper Jesse Guidi discovered the eerie, metallic blue-black western grapeleaf skeletonizer moth while hunting for another pest, the glassy-winged sharpshooter. According to the University of Florida's Entomology and Nematology department, the non-native Harrisina metallica is originally from Arizona and New Mexico and typically found in Florida and the Eastern half of the United States. But now Napa County officials and growers are concerned the pests are setting up shop in their local vineyards.

"We do not want this pest to become established in Napa County," Tracy Cleveland, Napa County Agricultural Commissioner told CBS. That's because Farm Progress says it's a "serious, destructive pest" that's so voracious, it can destroy an entire vineyard.

"All larval life stages are voracious feeders that cause extensive damage to grape leaves, including partial or complete defoliation of grapevines," Greg Clark, former Napa County Agricultural Commissioner told the outlet in 2015. "Excessive feeding can damage fruit, lead to secondary fungal damage, and grape cluster rot."

Luckily, Farm Progress says that it's easy to spot whether a leaf has been terrorized by the infamous skeletonizer. When larvae are done feeding, there's usually nothing except a "distinctive lacy-skeletonized leaf with only the main veins remaining." They also say using insecticides or releasing thousands of parasites such as Apanteles harrisinae and Amedoria misella can help get the pest population under control.

For now, CBS says that the Napa County community is urged to "immediately" bring any Western grapeleaf skeletonizer caterpillars or adult moths to the Agricultural Commissioner's office, where they can help identify them. Residents and growers alike are also advised to check any incoming farming equipment for the invasive pest.