They have a victory for now, but opponents of aerial spraying of a substance that discourages the light brown apple moth from mating say they fear the state may resume the practice a few years from now.

The California Department of Food and Agriculture announced Thursday it would cease spraying synthetic sex pheromones designed to confuse male light brown apple moths and instead will release sterilized insects to interfere with the breeding cycle of the pest.

The moth consumes hundreds of plant species, including many of the crops grown in the Salinas Valley. The $3.8 billion agricultural industry is Monterey County's economic engine. Aerial pheromone spraying last fall to prevent the moth's spread sparked lawsuits in both Monterey and Santa Cruz counties, which spray opponents won.

Carmel Valley resident John Russo, who founded Stopthespray.org, said Friday while he's pleased by the CDFA's decision to stop spraying, opponents need to continue to advocate for farming practices that are less dependent on chemicals.

"At this point, I'm staying focused on the positive aspect of the announcement," Russo said.

But given that eradication plans can span decades, Russo said it's possible aerial treatments against the moth could resume in the future.

Because use of sterilized insects to control Mediterranean fruit flies and pink bollworm moths has proved efficacious, it's unlikely the state will resume aerial spraying in urban areas, CDFA spokesman Steve Lyle said.

"Our goal is get (halt) this infestation where it is and not have it spread," Lyle said.

Moth release set for 2009

The first batch of sterilized moths - bred and raised in a U.S. Department of Agriculture laboratory in Albany - will be released in 2009, with releases continuing through 2011 and peaking at 20 million moths per day.

Lyle said at this point there are no standards for measuring how effective the sterile moths will be in causing the overall apple moth population to decline.

The insect, which the U.S. Department of Agriculture says threatens more than 2,000 varieties of California plants and crops, was first spotted in the state in March of last year. The first round of pheromones was sprayed over Monterey and Santa Cruz counties starting last fall.

The sterile moths will function in the same way as the pheromone, causing confusion among mating moths and reducing the number of fertilized eggs, thereby causing the collapse of the moth population.

During the announcement Thursday, CDFA Secretary A.G. Kawamura said government scientists were able to produce a stable colony of sterile moths much faster than the five to seven years anticipated.

Lyle said the moths are available so much sooner because of advances in feeding, housing and releasing the moths.

Group wants spray vote

Breeding the sterile moths will cost about $37 million annually, just half the cost of the aerial sprays, said John Connell, the CDFA's director of plant health test prevention services.

In the meantime, ground treatments using sticky traps and other bait with pheromones and a pesticide will be used in populated areas, including the Central Coast.

Another opponent of aerial spraying, Helping Save Our Peninsula's Environment, an advocacy group, issued a statement Thursday saying it wants state law changed to require a vote before populated areas are sprayed with chemicals.

Monterey resident Dennis Knepp said he believes the CDFA changed course in a political move to ensure the flow of federal money to finance the emergency eradication program.

"I think this program is still a big mistake," Knepp said.

THE ASSOCIATED PRESS contributed to this report. Contact Dawn Withers at withers@thecalifornian.com.