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Millions of sterile moths on the way


Published: March 26, 2010

THE NUMBER of sterile light brown apple moths being produced in a facility in Moss Landing as part of state and federal efforts to control the invasive pest will increase dramatically over the next six months, an official told The Pine Cone this week.

Since early 2009, researchers have been raising and sterilizing male moths in a former brick plant across from the Moss Landing power station. The plan is to release the moths in Monterey and other counties so the destructive apple moth population will shrink.

This week, a U.S. Department of Agriculture spokesman said the production of sterile apple moths will peak in late summer at as many as 4 million per week.

“Right now, we are producing about 40,000 sterile moths per week,” Larry Hawkins said Monday. “By mid-April, we will be producing about 100,000 per week.”

And by mid-May, with the arrival of four new moth-rearing modules at the Moss Landing facility, officials expect production will increase to 500,000 weekly.

In September, “when all of the new equipment is at capacity, we anticipate we will be producing 3 million to 4 million sterile moths per week,” Hawkins said.

So far, the only area in California where sterile moths are being released is Carneros, a wine region in Sonoma and Napa counties.
However, it’s not yet clear if the extra moths will be released only in those two counties, or in other areas in California affected by the moth’s destruction.

“At some point in time, we will want to release the moths in areas that are generally infested,” Hawkins said. “We haven’t determined where that is going to be.”

But Hawkins confirmed sterile apple moths wouldn’t be released in Monterey and Santa Cruz counties this year.

The state has warned that the Australian apple moth, could cause millions of dollars in damage to fruits, vegetables and plants. Last week, a California Department of Food and Agriculture spokesman conceded the state wouldn’t be able to eradicate the apple moth, only to control the insect.

Dropping moths from planes

Until now, workers have released moths by hand, which has allowed only a relatively small number of insects to be released each time.
But with millions more moths being produced by late summer, officials are working on other ways to release the insects in much greater numbers.

Hawkins said there are plans to distribute moths from vehicles using a “release machine” Hawkins said.

“You mount the devices on the bed of a pickup truck, for example,” Hawkins said. “You can drive around the perimeter of a vineyard and release them mechanically.”

There are also plans to release the insects in even greater quantities by air.

“The aircraft flies over the area and releases the moths from the machine,” he said.

Additional studies are needed before those release methods are used, Hawkins said.

Cost of new moths

Ramping up production of sterile moths at the Moss Lading facility will cost about $350,000, which will go toward for the four new modules — moth-raising chambers that look like trailers.

“There will be additional staff hired,” Hawkins said. “But we think things are geared to where it doesn’t take a lot of people to run” the operation.

The insects arrive at Moss Landing in their larval stage after being hatched in Alameda County. They are placed in the chambers, where they are raised to adulthood. The chambers allow researchers to control the temperature, light and humidity for the moths.

“The chamber is like a big metal closet with a light source, which draws moths to the light when they emerge,” Hawkins explained. “When they approach the light, they are actually flying into a tunnel with a very light negative vacuum pressure.”

The vacuum hose draws the moths to the cooling chamber, and the cold puts the insects into hibernation, in which they will remain during the sterilization process and until they are released.

EIR certified

On Tuesday, the state certified the environmental impact report for the LBAM program. The EIR found it was unlikely treatments in the moth program would cause human or environmental damage and that more harm would be caused by widespread pesticide use by private parties in absence of the program.

The state is currently only considering the the release of sterile moths and the placement of pheromone twist ties on trees and plants to get rid of the insect, the EIR said.

In September and October 2007, the state conducted aerial spraying of moth pheromones — a synthetic chemical intended to confuse males and make it difficult for them to locate potential mates — over Monterey and Santa Cruz county neighborhoods.

But the operation ran into heated opposition among residents who said the pheromone made them sick. Environmental groups filed lawsuits over the LBAM aerial-spraying program.

The state argued the LBAM infestation was an emergency, exempting the aerial-spraying program from environmental review.