Light brown apple moths prompt quarantine in Mendocino County

The discovery of three light brown apple moths this week near Fort Bragg is triggering a quarantine to limit further spread of the non-native pest that feeds on some 2,000 plant species and their fruit, including wine grapes.

At least 17 other counties, including Sonoma and Napa, have quarantines in place.

It’s not the first time moths have been located in Mendocino County, County Agricultural Commissioner Chuck Morse said. The Ukiah Valley was under quarantine between June and October of last year, he said.

Officials attacked the problem with strips that release sex pheromones, making it difficult for male moths to find the females and mate, Morse said.

He’s hoping for similar results in Fort Bragg, but it has not yet been determined whether they would be successful.

The first Fort Bragg-area moth to be found was trapped in June. The agriculture department set additional traps to gauge the extent of the problem but no other moths were captured until October, when a single male was found in a trap south of Fort Bragg, Morse said.

Beginning April 1, the department set out a new round of traps, which yielded three male adults. Morse and state agriculture officials are now in the process of establishing quarantine lines to attempt to contain their spread.

He also is expanding the moth- trapping area to better make that determination.

There are few agricultural crops grown on the Mendocino Coast and the quarantine is expected to affect primarily nurseries and people who grow vegetables for farmers markets.

The moth was first identified in California in 2007 in Berkeley and was found a year later in Sonoma County. Today most of the Bay Area is under quarantine, with an area that extends to Windsor, Sacramento and Monterey. Small isolated quarantine zones can be found as far south as San Diego County.

The moth has caused damage to strawberries, raspberries, blackberries and nursery stock in the Central Coast around Monterey, said Steve Lyle, a spokesman for the state Department of Food and Agriculture.

“Those are largely organic crops,” Lyle said.

In Sonoma County, the moth doesn’t seem do much damage to wine grapes, the county’s premier crop, said county Agricultural Commissioner Tony Linegar. But the moth “is becoming a rather common pest” and it does cause problems for landscape nurseries who ship their products to other parts of the state.

“That’s how this pest really moves is on nursery stock,” Linegar said.

In the effort to contain the moth, the landscape nurseries must be regularly inspected. A discovery of larvae requires destroying plants and treating portions of the nursery in order to ensure the removal of the pest.

Some scientists believe the moth is becoming permanently established in the cooler California climates that it favors, Linegar said. But certain international trading partners, including Mexico and Canada, might balk at accepting fresh agriculture products from California if the state and the U.S. Department of Agriculture stopped making efforts to contain the pest.