For farmers throughout San Mateo County, the much-ballyhooed light brown apple moth is living up to its reputation as a pest — though not in the usual way.
Much has been made of the pint-size insect, primarily because major citizen protests erupted after hundreds of residents in Santa Cruz and Monterey counties reported health problems after state and federal agriculture officials conducted an aerial spraying program last fall to keep the moths from mating.
In June, officials announced that they would shelve a plan for additional spraying in California. Instead, state officials will try to control the invasive pest with a program that releases sterile moths in an attempt to interrupt mating patterns.
The light brown apple moth is considered a potential threat to California’s estimated $32 billion agriculture industry because it eats so many different kinds of crops and plants, officials with the California Department of Food and Agriculture said.
So far, the moth — which immigrated to California from Australia, New Zealand or Hawaii in 2007 — has not caused any crop damage, according to CDFA spokesman Steve Lyle. Traps in San Mateo County have caught 359 moths, compared with nearly 8,500 in neighboring San Francisco and nearly 18,000 in Santa Cruz County.
However, for the 88 growers and other plant-based businesses within San Mateo County’s moth-quarantine zone — which was expanded in June and now covers nearly half of the county — the winged herbivore has led to waves of frequent inspections, pesticide sprays and other regulatory hassles, farmers say.
“I can’t always afford to spray [for pests], but I can’t afford to throw flowers away if they find a moth, so it’s a dilemma,” said Pete Vanos at Westland Nursery in Pescadero, which grows and sells cut flowers from freesia and lilies to rarer breeds.
County agricultural inspectors found a moth in Vanos’ greenhouse this year, but he was able to prove the pest was gone and his crop was clear within a few days — before he suffered significant losses.
David Repetto, who runs Repetto’s, a cut-flower market in Half Moon Bay, saw one of his greenhouses shut down for two weeks after inspectors found a suspected moth.
The pest in question turned out to be something else. Nonetheless, Repetto spent hundreds of dollars on pesticides — which he doesn’t normally use, since he sells flowers to Whole Foods — before his crop was given a clean bill of health.
Other farms, so far, have been lucky.
“Right now, the only impact on us is that I’ve got traps over every square inch of the ranch,” said Ed Riley, who runs Giusti Farms in Half Moon Bay. The farm grows plenty of produce that moths like to nibble, from Brussels sprouts to fava beans, but the sprays Riley uses to prevent other pests already work on the apple moth.
“It just means headaches and extra work for me to get the trucks out earlier in the day, because the inspectors go home by 3:30,” Riley said.
Keeping up with inspections has also taxed the staff at San Mateo County’s Department of Agriculture and Weights & Measures, whose inspectors have to check all 88 companies every 30 days — or every 14 days in some cases, commissioner Gail Raabe said.
Because there’s so much work to do, their staff is supplemented by inspectors from the California Department of Food and Agriculture and the U.S. Department of Agriculture, the latter of which reimburses them about $60,000 per year for mileage and other inspection-related costs, Raabe said.
Although prevention efforts may seem like more of a pest than the moth itself, they remain crucial to preventing future crop damage, Lyle said.
“There’s no question that a quarantine presents a hardship,” Lyle said. “But the way we operate, you react to the threat before it causes damage. If you wait until there’s damage, you’ve likely waited too long.”
How did the moths get here?
Human travelers aren’t the only ones who make their way to the Bay Area via San Francisco International Airport — thousands of insects and other pests are nabbed at security every year, and some agricultural experts think the light brown apple moth may have immigrated that way.
“The only place in North America that has the moth is the Bay Area,” said San Mateo County Agricultural Commissioner Gail Raabe, of the pest formerly only known in Australia, New Zealand and Hawaii.
Although county inspectors have not found any moths on commercial plant shipments coming into the Peninsula, “the assumption is it came in on nursery stock from those countries,” Raabe said.
No one can say for sure how the plant-eating moth arrived in sunny California, said Roxanne Hercules, spokeswoman for federal agricultural inspections at SFO and other airports.
Most commercial growers are cooperative and responsible when it comes to shipping products into the region, Raabe said.
However, products and pests can slip through.
“The data for San Francisco baggage indicates that 7 percent of passengers are likely to be carrying prohibited [plant or produce] items,” Hercules said.
Among commercial shipments — as opposed to plants or produce passengers might have picked up on vacation — federal inspectors confiscated 3,911 forbidden plant products in June 2008, Hercules said.
County biologists, who also check commercial shipments at the airport, looked at 18,239 shipments between July 2006 and June 2007, rejected 5 percent of those shipments for being infested or not having proper paperwork, and confiscated 1,163 pests, from small plant-destroying insects called scale to a trio of enormous African snails, Raabe said. — Beth Winegarner
By the numbers
359: Light brown apple moths found in San Mateo County
186: Locations in which moths were found
88: Companies within the quarantine zone, including nurseries, growers and green-waste haulers
$168 million: Gross production value of farming in San Mateo County, 2006
$60,000: Amount San Mateo County’s Department of Agriculture is reimbursed by the USDA for inspection-related expenses, per year
Source: San Mateo County Dept. of Agriculture, Weights and Measures; California Department of Agriculture