Grapegrowers Fight Apple Moth

Progress and setbacks as LBAM quarantines continue in California wine country

by Paul Franson
LBAM light brown apple moth
An adult light brown apple moth.
Sacramento, Calif. -- There's good and bad news in the fight against the light brown apple moth (Epiphyas postvittana), or LBAM.

The good news includes a report that the pest has been eradicated in parts of Santa Barbara County, and that a trial using sterilized male insects is planned in an isolated area of the Carneros district in Napa County where moths have been found.

The bad news is that the quarantine area in the state has expanded significantly as more moths are discovered, including, for the first time, in the San Joaquin Valley.

According to the California Department of Food and Agriculture, the statewide LBAM infestation has grown in density and range in 2009. This summer the apple moth did considerable damage to berry fields near Watsonville in Monterey County, and more than 110,000 moths have been trapped in California.  

Approximately 3,473 square miles are now under quarantine within California.

State and federal quarantine regulations prohibit the movement of all nursery stock, all cut flowers, and all host fruits and vegetables and plant parts within or from the quarantined area unless they are certified as free from the pest by an agricultural official; are purchased at a retail outlet; or were produced outside the area and are passing through in accordance with accepted safeguards.

The devastating moth is native to Australia and is found in New Zealand, the United Kingdom and Hawaii. More than 2,000 plant species are known to be susceptible to attack by this pest, and more than 250 crops. The moth feeds on host plants and damages or spoils the appearance of ornamental plants, citrus, grapes and deciduous fruit tree crops. It also threatens California's environment including cypress and oak trees by destroying, stunting or deforming young seedlings and damaging new growth in the forest canopy.

Gone from Santa Barbara County
State and federal officials say that they have eradicated an LBAM infestation in the area of Carpinteria in Santa Barbara County. The federal domestic quarantine for the entire county and a 10-square mile state interior quarantine, both established in early 2008, have been lifted by the USDA and CDFA.

CDFA treated the area using pheromone-infused twist ties applied by ground crews to host plants, trees and fence posts following the detection of two light brown apple moths. The area is saturated with so much female pheromone that it is impossible for the male moth to find a female. Mating disruption is an effective technique in the low-level populations that occur in small, isolated LBAM populations.

The conditions of the quarantine were met based on extensive trapping results that indicated the absence of LBAM populations for three consecutive generations. LBAM trapping activity will continue in Santa Barbara County to ensure it remains free of the pest.

Dave Whitmer
Napa agriculture commissioner David Whitmer.
Napa to try sterile insects
In Napa County, agricultural commissioner David R. Whitmer reports more moths have been found, and now a significant portion of Napa County is currently under quarantine for the LBAM since movement of plants, green waste and harvested commodities may be significant sources of the artificial spread of this pest.

Growers and wineries will not be allowed to move harvested grapes or any green waste from properties unless the grower obtains a compliance agreement. Wineries will soon be requiring proof of a compliance agreement when purchasing grapes from within the quarantine area.

Light brown apple moths have been found in Carneros, American Canyon, the City of Napa and surrounding area, Yountville and St Helena. As a result, a single quarantine area exists. The county has identified more than 450 winegrape growers within the quarantine area.

Unfortunately, Whitmer says, the state and federal government LBAM eradication program cannot proceed with significant eradication measures due to legal action and future completion of an environmental review and assessment. However, Whitmer says that state and federal agriculture officials are developing sterile insect technology to combat the infestation, and a trial to eradicate the bugs using release of sterile insects is planned after review of an environmental assessment indicates no negative consequences.

The area to be treated is an isolated 3 square miles on the Napa-Sonoma border where male moths have been found, which may have blown in from the Bay Area. Whitmer says that no viable female moths or larvae have been found in the county and so far, no environmental damage or harm to vineyards has been detected, but the USDA regulations still require a quarantine, which is a nuisance at best to growers.

Other techniques can be also used to eliminate the moths. Test areas in Napa and Oakley in eastern Contra Costa County have been treated via ground equipment with Bacillus thuringiensis kurstaki (Btk), a biologically based pesticide that is effective against early larval stages of most lepidopterans, including LBAM. Whitmer says he hasn't ruled out the possibility of using bacillus.

In addition, an LBAM-specific pheromone can be used to eradicate moths, as was done in Santa Barbara.

New detections expand quarantine
Unfortunately, both new and expanded quarantine boundaries are in effect in several California communities due to recent detections of the light brown apple moth. The new boundaries will quarantine plants, flowers, fruits and vegetables grown in some areas of Contra Costa, San Benito, Monterey, San Joaquin and Solano counties.

Three new quarantine boundaries have been established: approximately 18 square miles in the Manteca area of San Joaquin County, the first quarantine in the San Joaquin Valley; approximately 16 square miles in the Gonzales area of Monterey County; and approximately 15 square miles in the Fairfield area of Solano County.

Two currently quarantined areas have been expanded: approximately 12 additional square miles in the Hollister area of San Benito County; and approximately 32 additional square miles in the regulated area of Contra Costa County.

Preparations are also underway for forthcoming quarantines in the Long Beach area of Los Angeles County and in the Los Osos area of San Luis Obispo County, due to recent detections of the pest.

Currently one fifth of all winegrapes in Sonoma County are under quarantine.

The quarantine applies to residential and public properties as well as plant nurseries, farms and other commercial enterprises. Residents are asked to consume fruits and vegetables from yards and gardens in the area rather than removing them from the property. Landscapers and yard maintenance companies will be among the businesses placed under compliance agreements to ensure that yard waste is disposed of properly.

People who are unsure if they are within the quarantine zone are asked to assume that they are. Maps of the quarantine zones are available at cdfa.ca.gov/phpps/PDEP/lbam/quarantine.html.

EIR comment period opens
In final news from the LBAM front, public meetings are scheduled for Long Beach, Carpinteria, Fresno, Sacramento, Sonoma, Watsonville and Oakland about the draft Environmental Impact Report (EIR) for the light brown apple moth program, which has been released for 60-day public review. The California Department of Food and Agriculture will also be accepting written comments about the document.

"The draft Environmental Impact Report is not a treatment plan but a comprehensive document used for evaluating options and to identify potential significant environmental impacts as well as other components of the program since it began in 2007," says John Connell, director of Plant Health and Pest Prevention Services at CDFA.

The EIR evaluates the environmental effects of various strategies and methods for treating LBAM in portions of the state where infestations have been identified.

For more information on the light brown apple moth program, visit cdfa.ca.gov/lbam.

Napa light brown apple moth quarantine map
Map of quarantined Napa County area.
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