County agricultural officials are dealing with a second infestation of the light brown apple moth, an invasive pest.
Two adult male apple moths were found in September in a canyon off Zenon Way in Nipomo. The discovery prompted state and county farm officials to establish a quarantine area there.
The quarantine applies to farms, nurseries and other businesses that could spread the moth. Growers in the quarantine area are required to undergo regular inspections, said Marty Settevendemie, deputy county agricultural commissioner.
One of these inspections turned up a larva of the moth. Later, a third adult moth was found four miles east of the initial Zenon Way discovery location.
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Officials are planning an eradication effort in the Nipomo area. The effort involves placing thousands of twist-ties containing the moth’s mating pheromone in shrubbery.
The pheromone overwhelms male moths with the scent of females and prevents them from locating real females to mate with. Eventually, the insects will die out.
The quarantine area covers a 1.5-mile radius, or about nine square miles, around the Zenon Way spot. It includes portions of Mesa View Drive and West El Campo and Los Berros roads.
County officials are also conducting a high-density trapping effort around the spot where the third moth was found. They want to determine if a viable population is there.
“We are waiting to see what happens with that,” Settevendemie said.
In July, the first population of the insect was found in Los Osos. An eradication program has already been carried out there.
A similar program is planned for Nipomo. However, rainy weather has forced farm officials to delay it until March or later, said Rich Little, another deputy county agricultural commissioner and an entomologist.
“The rain decreases the effectiveness of the pheromone in the twist-ties,” he said.
When the date for the eradication is set, county officials will hold an open house in Nipomo for the public to ask questions and find out more about the moth and the eradication procedure. County, state and federal agricultural officials will participate in the public meeting.
The light brown apple moth is from Australia and feeds on hundreds of different types of plants during its caterpillar stage. It can stunt and deform seedlings, disfigure ornamental plants and damage native species including oaks and redwoods.
It can also destroy a variety of crops including citrus, grapes and deciduous fruit. Last year, the moth damaged crops in Watsonville and Monterey County.
Reach David Sneed at 781-7930.