Use of pheromone-treated twist ties to combat an invasive Australian moth — a less controversial alternative to the aerial spraying sparking widespread protest and health concerns — is on hold in San Mateo County while the state re-evaluates if they’re working.
"The decision is driven by science” rather than the current brouhaha over the pheromone, said Steve Lyle, director of public affairs for the California Department of Food and Agriculture.
The CDFA notified the county that twist tie treatments for the Light Brown Apple Moth will not start the week of June 2 as planned. Instead, the ties slated for San Mateo, Foster City and Belmont are on hold until further notice.
The same is true for all upcoming twist-tie treatments, Lyle said.
The CDFA found new detection of the pest throughout the infected regions even when twist-ties are used. The CDFA wants to re-evaluate if the method is working or can be improved.
"Figuring out how to treat certain areas is a complex equation and as the variables change the approach needs to be evaluated,” Lyle said.
Lyle emphasized the decision was sparked by the moth’s detection rather than the surrounding debate about the eradication method and the actual danger posed by the creature.
The moth is native to Australia but found in New Zealand, Ireland, the United Kingdom and Hawaii. More than 250 cultivated and native plant species are known to be susceptible to attack by the moth including various ornamentals, oaks trees, stone fruit, applies, grapes and citrus. The moth — specifically the caterpillars and eggs — destroys, stunts the growth of or deforms young seedlings, damages the appearance of plants and injures fruit crops.
Checkmate, the pheromone used to combat the moth, disrupts its mating cycle for approximately 90 days. Opponents claim it is a pesticide that causes a range of ills, including rashes and breathing problems.
While the three cities sidestep the twist ties, the program is already under way in other parts of the coastal county.
In February, the state began ground treatment at seven sites in Pescadero and six places in Half Moon Bay on trees, shrubs and fence posts within a 200-meter radius of each moth found. At the time, 111 male moths had been trapped in 75 locations throughout San Mateo County since the first appearance the previous April in Belmont.
Initially, each confirmation brought an agriculture quarantine of 1.5 miles around each area, ranging from 11 to 23 square miles. As the infestation grew, both locally and throughout the Bay Area, the state stepped up its eradication plan to include the twist ties and aerial spraying.
A majority of rallies and outcry against the spraying has centered on San Francisco and other areas where it was set to begin. San Mateo County was not anticipated to begin the process until August.
However, county leaders haven’t been inactive. A light brown apple moth advisory committee of stakeholders and officials from affected jurisdictions is currently meeting. On Tuesday, Supervisor Jerry Hill asked the county Health Department and the task force to report back on the spray and possible ramifications.
Michelle Durand can be reached by e-mail: firstname.lastname@example.org or by phone: (650) 344-5200 ext. 102.