San Diego Avocado Growers Brace For New Invasive Beetle

By Susan Murphy, KPBS

A tiny Asian insect has arrived in San Diego County with the potential to cause widespread destruction to more than 100 of species of trees, including oaks and avocados.

The exotic beetle, called a polyphagous shot hole borer, was first detected in Los Angeles County in 2011. Since then, it has attacked 117 host trees in Southern California by spreading a fungus that blocks the tree's transport of water and nutrients, according to the Center for Invasive Species Research.

Now the beetle has turned up in a residential backyard in El Cajon. Farm Bureau Exeutive Director Eric Larson said avocado growers are concerned and bracing for an invasion.

"If they do find it, they’ll have to do the best they can to control where it is, even if that means removing limbs or even removing trees to keep it from moving on to other parts of groves or other parts of the county," Larson said.

Larson said there is no known solution to eradicate the pest, which can travel fast and fly 500 yards per stretch.

"One problem with avocado trees is quite often the crowns of the trees are all knitted together," Larson explained. "The limbs from one tree, they grow into another tree to create a canopy. So if the pest is found in an avocado grove, it’s going to be a real problem."

San Diego already is in a race against the oak borer beetle, which has destroyed nearly 100,000 oak trees, and the Asian citrus phyllid, which is threatening the region’s $80 million citrus industry.