As you may have already heard, the state of California plans to spray up and down the coast three to five nights a month for five years to eradicate the light brown apple moth, a newcomer from Australia. Hundreds of people in the Santa Cruz area, where spraying began last fall, reported respiratory problems. Legislation has been introduced to stop the plan and some towns like Albany (here’s a recent Contra Costa Times editorial by Albany Mayor Robert Lieber) are resisting. Our Alameda is in the area slated to be sprayed.
Not knowing much about moths, I called Dr. Jerry Powell the Berkeley entomologist who found the first light brown apple moth in his backyard blacklight trap in July of 2006. While Powell graciously declined to weigh in on the value of spraying–“insect control is not my field,” he said—he did point out that science does not indicate with any certainty that the apple moth (which he describes as “small, drab and maybe about a centimeter long”) will necessarily become a huge problem: “I think the crux of the matter is that the USDA classifies it as a potential pest and there’s a budget to keep it from spreading.”
What I found most interesting about my conversation with Powell—aside from the fact that it’s not every day I get to chat with people who’ve made a career studying insects (there’s a heck of a lot more of you tech people out there)—was that he made it quite clear there’s no way to predict how and where the apple moth might establish itself:
There is precedent for new moths coming in and not spreading elsewhere along the coast. There’s also a couple of examples of ones that have come in and spread. And there’s one that was in Southern California on the coast for 50 years and then suddenly began to spread inland. You certainly can’t predict what’s going to happen based on other species. It’s sort of anyone’s guess what would happen if you did not spray.
To be clear, the plan does not call for spraying pesticide, but rather synthetic moth pheromones designed to confuse the male moths and interrupt their breeding patterns. Powell:
It’s a kind of like a dust. They call it spray, but it’s a dust made of tiny plastic flakes on which the synthetic pheromone is affixed. And the way that kind of treatment works—or they hope it works—is that it causes so much confusion on the part of the males that they can ‘t find females. The hope is that it leaves a lot or most of the females unmated.
Call me crazy conservative, but I’d like to know, one, that these moths really, really are going to be a big problem if left unsprayed and, two, that the little plastic flecks with pheromones (as well as the other ‘inert’ ingredients included in the product) really, really don’t harm people.
For more information—-you must be curious now? The Pesticide Action Network has a pretty extensive description of the issue, including a timeline of moth-control related events and some background on aerial spraying and pheromones.