An invasive beetle that attacks more than 65 species of tree in California has been detected in San Jose, according to Santa Clara County agriculture officials.
The shothole borer, a non-native beetle, may have arrived in the South Bay years ago, the county says, and it has now been detected in the Santa Cruz Mountains, in the area of Zayante Creek south of Graham Hill Road, according to an Oct. 9 report from KSBW-TV.
The Santa Clara County Division of Agriculture announced the San Jose infestation on Aug. 23. Researchers are trying to determine the extent of the infestation.
The invasive shothole borer, about the size of a sesame seed, tunnels into host trees and introduces a fungus that serves as food for the beetles and their larvae. The fungus causes a disease that essentially blocks the trees from consuming water and nutrients, eventually killing them.
It's unlikely the county will be able to get rid of the shothole borer at this point, but it's possible to contain the infestation, acting Agricultural Commissioner Drew Raymond said. Most important now is identifying infested trees, he added.
The city's plan is to eventually inject the affected trees with a fungicide and insecticide to kill both the fungus and the beetles causing it.
"I'm glad the city is on this and has a plan to treat the trees," resident David Vieira said. He has been counting the weeping trees in his neighborhood and reporting it to the city arborist. "East San Jose is unfortunately tree canopy challenged. So we really can’t afford to lose these trees here, or anywhere else in the city."
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"We’re asking for the community’s help in identifying trees that have been attacked by invasive shothole borers, which will help us determine the extent of the infestation," Raymond said.
One way to identify an infested tree is to look for an entry or exit hole that is perfectly round and about the size of the tip of a ballpoint pen, the county said. Other signs include wet staining, gumming, frass (insect waste), boring dust and sugary buildup around entry and exit holes.
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Anyone who sees the aforementioned signs on trees on their property should contact the county Division of Agriculture at scc.agriculture@cep.sccgov.org or 408-918-4610.
The beetle is capable of killing 17 tree species, including the box elder, California sycamore, valley oak, Japanese maple and American sweet gum.
It's not clear to researchers how the pest arrived in the South Bay, but the beetle was discovered in Southern California in the early 2000s and has killed tens of thousands of trees in seven counties there, Santa Clara County said.
Learn more about the invasive shothole borer on the Santa Clara County website.
