Evidence of the insect, known as the tea shot hole borer, has been found in backyard avocado trees in more than a half-dozen locations in Los Angeles County, the Los Angeles Time reported Friday.
The tea shot hole borer is spreading a fungus, known as "Fusarium dieback," that scars tree bark and causes branches to shrivel and die, said University of California Riverside extension plant pathologist Akif Eskalen, who identified the fungus. The beetles carry the disease in their mouths.
It's not clear how the insect -- native to Sri Lanka, India and other parts of South Asia -- arrived in Southern California, but it has been infecting trees in the area since February.
California's commercial avocado groves, which produce 90 percent of U.S.-grown avocados, have yet to be harmed by the beetle, but commercial growers are concerned, prompting the California Avocado Commission to give Eskalen's team $100,000 in emergency funds to get a handle on the scope of the infestation.
"The challenge with the beetle is that it lives right inside the tree," said Jonathan Dixon, research program director at the commission. "There is very little you can do about it."
The beetles have already wreaked havoc on Israeli avocado groves, and scientists there have yet to find a predator or poison to neutralize the beetle.
"It's a serious threat," Eskalen said. "There is no cure."