Light brown apple moth strikes again

This week’s grape quarantine brings more unwelcome news to the local wine industry, which has been pounded recently by the excise tax threat and the danger of drought. This latest cause for alarm comes in the form of a tiny invasive pest called the Light Brown Apple Moth that is said to become a threat to the state’s fruit crops. In its caterpillar stage, LBAM, as it’s less than affectionately known, likes to feed on leaves and new plant growth, a potentially disastrous scenario in grape country.
Whether LBAM is a true menace remains to be seen but there’s no doubt that the quarantine is a threat to growers.
“To have a grape quarantine going into harvest will have a huge impact on a grower’s livelihood,” said Grant Raeside, executive director of the Sonoma Valley Vintners and Growers Alliance.
Sixth District Assemblyman Jared Huffman recently met with Raeside and is currently working with the federal officials to assess whether the moth is a real agricultural threat in Sonoma County. Huffman was responsible for passing legislation in Marin County that put processes in place for aerial spraying in residential areas. But he pointed out that Sonoma is different as it is an agriculturally dense area so the same residential spraying rules won’t apply.
“What we’re hearing from credible experts is that the LBAM is not a threat to grapes,” said Huffman. Indeed, critics maintain that both the scientific literature and the experience of farmers in other countries demonstrate that the insect causes little damage and can be easily controlled through normal farm practices.
“At this point,” said Huffman, “we need to take a look at the science and determine whether we need to quarantine or not and if so, what non-toxic eradication measures can we take to rid ourselves of LBAM.”
The moth was first seen in Australia and New Zealand. The pest attacks over 250 crops including citrus, and fruit tree crops as well as 2,000 host and ornamental plants like roses, jasmine and mums. LBAM’s presence in California was first confirmed in early 2007 by the California Department of Food and Agriculture and quarantines are currently in place in ten Bay Area and Central Coast counties: Monterey, Santa Cruz, Santa Clara, San Mateo, Contra Costa, Marin, San Francisco, Alameda, Solano and Santa Barbara. Isolated detections last year in Los Angeles and Napa counties have already been eradicated using twist ties that emit moth pheromone.
Twenty-two moths were found in Sonoma County last year and while this number pales when compared to the 40,000 moths trapped throughout California, it was enough evidence for state and federal officials to consider the pest a threat. Following the discovery, they decided to place a quarantine on a large southeastern portion of the county that affects the inspection and movement of crops.
The quarantine will be an agenda item at the SVVGA’s annual quality conference being held on Tuesday, March 10 at The Lodge at Sonoma. Cathy Neville, the new Sonoma County’s Agricultural Commissioner, will be on hand to address the topic.
“In the short term, my job is to work with growers to make sure they can move their product as long as it is LBAM-free,” said Neville. “Looking ahead a bit more, once the state’s environmental impact report becomes complete this summer, we can make plans for eradication.”
However, according to Ned Hill, owner of Parmelee-Hill Vineyards, LBAM larva are nearly impossible to distinguish from other moth larvae in the field. “The omnivorous leafroller and the orange tortrix are two other insects that have larvae almost identical to the light brown apple moth,” said Hill.
During quarantine, any larvae detected in the vineyard are collected and sent to the lab for verification – a lengthy process that will hold up harvest.
“From a shipping perspective, the quarantine is unacceptable as we won’t be able to move grapes outside of the area if the moth is detected,” said Hill. “We’re spraying proactively to prevent any type of larvae in the vineyard because we can’t afford time during harvest to wait for test results. It’s the best we can do at this time to protect ourselves.”