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.