The insect that could destroy California's avocado crop

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Orange County officials are looking for help stopping an invasive pest in its tracks as it threatens to spread to the state's avocado belt. 

The polyphagous shot hole borer, a beetle smaller than the size of a sesame seed, has chewed through so many trees in Orange County that the Board of Supervisors Tuesday approved $750,000 in emergency spending, effectively doubling their efforts to treat infested trees and remove the ones that cannot be saved. 

But the county's also looking for state help fighting the beetle as it continues to spread through Southern California and potentially outside of the region.

“There’s a sense that the state of California has basically has walked away from this,” said O.C. Supervisor Todd Spitzer. 

The borer was first discovered in an avocado tree in 2012 in South Gate, according to arborists and tree scientists at the University of California Riverside who have been working on ways to eradicate the pest and its accompanying tree-killing fungus. 

Since then, the California Avocado Association has spent approximately $2.6 million on researching the beetle infestation, said research program director Tim Spann. The National Parks Service has paid for beetle eradication in parks and the California Department of Food and Agriculture has kicked in another $31,000 to the fight, he said, but still, avocado farmers are worried. 

“Growers are frustrated,” he said. “They see the state response to things like fruit flies, other pests, and they wonder why we can’t get that same level of response for this pest.”

A spokesman for the California Department of Food and Agriculture says the state does not have a regulatory program for the polyphagous shot hole borer but the department has funded research. It is also participating in two task forces on the issue.

Avocado trees aren't the only ones at risk. Hundreds of other tree species including big leaf maple, California box elder, sycamores, and coast live oaks and willows have been attacked.

It’s actually the fungus that the Southeast Asian beetle grows inside the tree that kills it. So far, Orange County Parks staff estimate the shot hole borer has killed $1.4 million dollars worth of trees. Another 320 trees are being treated.

UC-Irvine tree experts are helping Riverside researchers in the search for a cure or natural predator to the borer since the insect has attacked dozens of sycamore trees on the Irvine university campus.

“It’s going to be a pest for our natural areas and homeowners,” Spann said.

Spann said the association found one beetle in San Luis Obispo County early this year. He said because the beetle seems to like a variety of trees, there's concern about it spreading to other groves in the Central Valley.

Sptizer called the beetle a public safety issue because a dead tree could fall on park patrons.

San Bernardino, Riverside, San Deigo and Los Angeles County parks officials have identified several locations where the beetle has infested trees, said Orange County Parks Director Stacy Blackwood.

As an immediate response to manage the spread, especially as the summer season lends itself to camping trips, Blackwood said Orange County will not allow people to bring camp firewood to parks.

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