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Local farmers advised on Light Brown Apple Moth - One discovered so far, in Bonsall; second would mean a quarantine

Between 80 and 90 farmers attended a March 23 informational meeting on the Light Brown Apple Moth.

The meeting was held at the San Diego County Farm Bureau office in Escondido and was presented by the County of San Diego’s Department of Agriculture Weights and Measures and the California Department of Food and Agriculture. The topics included information about the pest and its recent find in Bonsall, and possible requirements in case quarantine is triggered by a second find.

“It was very well-attended,” said San Diego County Farm Bureau executive director Eric Larson.

On March 2, a Light Brown Apple Moth was found in a Bonsall trap. “We’ve got one moth. If they find two, that triggers quarantine and no one will be able to ship agriculture products until their farm is inspected,” Larson said. “They couldn’t sell anything for two to three weeks.”

Despite the moth’s name, the apple is only one of more than 250 crops and more than 2,000 plants on which the Light Brown Apple Moth is suspected of feeding. The caterpillar form of the moth feeds on leaves, buds, shoots and fruit.

The second moth would need to be found within three miles of the first find and within one lifecycle, which at this time of year is approximately 60 days, to trigger a quarantine.

The Light Brown Apple Moth is native to Australia, but 13 California Counties are already considered infested areas. Twelve of those counties are in the Bay Area, and Santa Barbara County is the southernmost California county considered to be infested. The infestations in the California counties and in Hawaii are currently the moth’s only presence in the Western Hemisphere.

Females deposit egg masses, which usually consist of between 20 and 50 eggs, on upper leaf surfaces or on fruit. At the larval stage the moth disperses and constructs silken shelters on the underside of leaves, often near a midrib or a large vein. Older larvae roll together leaves and buds or fruit with webbing, and the surface feeding by the larvae results in the damage to fruit.

Adult moths are light brown or yellowish with varying amounts of darker brown color. The typical wingspan ranges between 16 and 25 millimeters. Female adults are larger than males and typically have fewer distinct markings, and the females often have a distinct spot in the middle when their wings are closed.

The larvae are green and reach approximately 18 millimeters at maturity, while the pupae are brown and are approximately 11 millimeters long. Light Brown Apple Moth eggs are pale white and are deposited slightly overlapping each other.

In the event of a quarantine, host materials will include all live nursery plants, all fresh green waste material and cuttings from any plants, all fresh garlands, wreaths, cut flowers, and greens produced within the quarantine area, all harvested fruits and vegetables produced within the quarantine area except certain commercially-produced crops, and all machinery and equipment used in the growing, harvesting, processing, and hauling of host plants or plant parts. The quarantine would not apply to seeds removed from fruit, leafless and dormant nursery stock which is either bare-rooted or in containers where all leaf litter and weeds have been removed, or dying or dead plant material which has been ground up and moved directly to a sanitary landfill or state-licensed compost facility within the quarantine area.

Host materials can only be moved within or beyond the quarantine area with a certificate issued by an authorized governmental agricultural official stating that the article or commodity came from a location free of any form of the moth, with a certificate issued by an authorized governmental agricultural official stating that the article or commodity has been inspected or treated properly and is apparently free from any form of the moth, if purchased at a retail sales location and with a sales receipt, or if the article or commodity was produced outside the quarantine area and is being transported through the quarantine area without delay in vehicles or containers which prevent infestation. Agricultural machinery or equipment can only be moved if cleaned and treated to the satisfaction of the California Department of Food and Agriculture or the county agricultural commissioner.

While an internal state quarantine area would encompass a 1 1/2-mile radius around each find, a federal quarantine preventing products from being shipped outside the state could encompass a larger area. “It could be possible that the quarantine area would be the entire county,” Larson said.

Because host materials could be moved with a certificate of inspection and treatment, some farmers are seeking such certification in advance of a possible quarantine. Currently such inspections require overtime work by Department of Agriculture Weights and Measures inspectors, although AWM is considering the possibility of utilizing outside contractors to meet requests. “It depends on the demand for the inspections,” Larson said.

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