How monumental estimates of a tiny invasive moth's economic and environmental impacts are threatening San Francisco with aerial spraying
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When retired entomologist Jerry Powell caught two tiny light brown apple moths in a blacklight trap in his Berkeley backyard last winter, he had no idea of the furor his find would unleash especially in the communities that were subsequently sprayed with female moth pheromones, a process that could come to San Francisco this spring.
Native to Australia and now found widely in New Zealand and the United Kingdom, the LBAM (or Epiphyas postvittana, as it's known in bug circles) is classified as a plant pest, but it had never before been reported on the United States mainland, though it was found in Hawaii in the late 1880s.
So its discovery, first in Powell's trap in February and then throughout the Bay Area and the Central Coast in March 2007, drove the US Department of Agriculture to declare a statewide emergency and issue quarantine and extermination directives.
The USDA's problem, as Powell explained, is that unlike many moths, which only lay eggs on oak trees or eat holes in sweaters, the LBAM can lay eggs on and eat many, many plants.
"From each batch a hundred tiny caterpillars hatch and feed on a wide variety of shrubs and trees, using silk to tie the leaves up into bundles," Powell told the Guardian.
According to the USDA's Web site, this pest could infest up to 80 percent of the continental US and attack 2,000 types of plants, causing huge economic and environmental damage.
Officials with the California Department of Food and Agriculture estimate the LBAM could cause up to $640 million annually in crop damage and control costs in California alone.
So starting last summer the CDFA required nurseries to either destroy infested plants or treat them with chlorpyrifos, an organophosphate pesticide derived from World War II nerve gas.
The agency also made ground applications of Bacillus thuringiensis (a genetically engineered bacteria) and hand-applied female moth pheromones in other infested areas, including Napa, Vallejo, and Mare Island.
But the agency's most controversial act was the spraying of entire communities, including Santa Cruz, with Checkmate, a synthetic female moth pheromone made by the Oregon company Suterra. Since male moths use the real pheromone to detect females, flooding an area with similar-smelling stuff is supposed to confuse them and prevent mating.
The controversy, according to four lawsuits filed in Monterey and Santa Cruz counties, in which 73 percent of the moths have been found, began when the CDFA acted with minimal notice, without fully disclosing Checkmate's contents until after the spraying occurred, and without adequately demonstrating that the moths were enough of an emergency to exempt the spraying from the California Environmental Quality Act.
Not to mention the sentiment, expressed by numerous members of the sprayed-on communities, that they felt as if they had been airlifted into Vietnam. For three nights in a row crop dusters, flying at 500 to 800 feet, traversed the skies, coating homes and gardens, parks and playgrounds with scentless, invisible, and largely untested female moth pheromones while freaked-out citizens were advised to remain indoors to avoid unwanted exposure.
Numerous health complaints were recorded after the spraying, along with questions about the scientific efficacy of the plan and the worry that the CDFA had paved the way to do an end run around due process and next time could use heavy-duty pesticides.
Gina Solomon, senior scientist with the Natural Resources Defense Council, told the Guardian the spray's contents are everyday chemicals, often labeled natural or organic, that degrade pretty rapidly into nontoxic by-products.
"But we did have a concern about tricaprylyl methyl ammonium chloride, a mild respiratory irritant, which could be of concern in a high dose to sensitive asthmatics," Solomon said.
Solomon gave the CDFA credit "for not picking a pesticide off the shelf," adding, "But it's funny to see them trying to do the right thing, then tripping up over the public process. People don't like planes going overhead spraying stuff and feeling like this is happening without their consent. I feel that if [the CDFA] is going to be inflicting this stuff on us, they need to let people know exactly why."
And with some scientists claiming that pheromones aren't powerful enough to attract every single moth, Solomon is concerned the CDFA could decide to spray more toxic stuff.
"They could technically spray an insecticide, but I guarantee they'll face a major protest, and it wouldn't make any sense," Solomon said. "For all its nastiness, the moth is not a human health threat. It's a threat to agriculture, nurseries, and gardens. We're not talking about malaria."
Retired entomologist Powell suspects the LBAM was well established in California when he found it, given that it was trapped in a dozen counties within the next month.
"They had probably been here a few years before they happened to bumble into my light trap," he said. "And whenever you have anything that feeds on all kinds of plants, it doesn't become a general defoliator but gets scattered around and causes minor damage. The problem is for nurseries that were forced to shut down and fumigate, but it's not likely to become a noticeable pest in the garden. It's likely to attract parasites and predators of similar species in the area."
James Carey, a professor of entomology at the University of California at Davis, is not a specialist in the LBAM. But he does know about invasive biology, having worked on the Mediterranean fruit fly. And in Carey's opinion, the moth can't be eradicated. It's already widespread, he said and disruptive mating pheromones have never been able to eradicate anything.
"It's not numbers that matters, but numbers of locations," Carey told the Guardian. "It's like metastatic cancer, where it's not a matter of a tumor but of tens of thousands of tumors. So any [pockets of moths] that are not 100 percent eradicated can repopulate entire areas."
He acknowledges the USDA's valid pest-related concerns. "But their entomologists should be able to argue that eradication is feasible, or face the facts that without effective tools not only to eradicate but to detect the moth it's not possible," he said. "Pheromones are weak tools; not all moths come or respond to them. Even in an orchard they don't work that well."
Casey warned that the CDFA will try to say that if we can't eradicate the moth with pheromones, we'll have to spray more pesticides. "But what if you can't eradicate it because it's too far gone?" he asked.
As for the unlikely scenario in which fixed-winged aircraft fly sideways between high-rises and the Transamerica Pyramid as they spray clouds of pheromones across the Castro, Chinatown, and beyond, Carey observed, "These moths can live in little pockets, so San Francisco will become a reservoir for them."
The CDFA's Steve Lyle told the Guardian that at this point the agency has completed treatment for 2007 and is evaluating what it will do in 2008 and where it will do it.
"It's fair to say that the entire program is being assessed, but we have made no definitive decisions and made no announcements," Lyle said.
With the Office of Environmental Health Hazard Assessment reassessing whether Checkmate causes harm to people, plants, and pets, Lyle added, "The moth is of serious concern to the feds. Unfortunately, this invasive pest is established in an urban area."
USDA public affairs specialist Larry Hawkins was a little less vague. "Since LBAM has been found in San Francisco proper and in the East Bay, these areas are likely to be treated in 2008," he said. "But we're considering whether to treat them through ground applications or aerial application."
Hawkins said any control action "will be preceded by informational meetings with the public, so any actions will be fully disclosed."
David Dillworth, executive director of the nonprofit Helping Our Peninsula Environment, which is suing the CDFA over the Monterey spraying, advised San Francisco to get proactive and lean on its elected leaders.
"San Francisco still has time to get Nancy Pelosi and Dianne Feinstein, whose backyards will be sprayed, to put pressure on USDA to stop the eradication, since at this point all they can really do is control the moth," Dillworth said.
Pelosi's press secretary, Drew Hammill, told the Guardian that Pelosi is "checking with state and city officials regarding the spread of this species.
"While the Speaker understands the consequences this moth can have on our precious ecosystem," Hammill said, "she is also concerned about the prospect of spraying any substance into the air in our city and its possible effects on public health and organic farming in our state."