The century-old sycamore on David Fleming’s El Cajon property was the focal point of his hacienda style home, with five trunks and a lush canopy of golden leaves.
It’s now ground zero of a San Diego infestation by the polyphagous shot-hole borer beetle, a pernicious pest that has ravaged backyards, street trees and arbors in Los Angeles and Orange Counties. So far, there’s no solution.
Unlike other insects that target just a few species, the shot-hole borer beetle is an equal opportunity pest, infesting at least 286 tree species and posing the potential for widespread destruction.
Its hosts include California natives such as coast live oaks and sycamores, and key agricultural crops, including avocado.
“It’s extreme,” said Tom Launder, an Oceanside arborist who flagged the infestation at Fleming’s home. “It has the potential to be one of the worst (pests) that we’ve seen in decades.”
The shot-hole borer beetle injects trees with a fungus, which it them “farms” for food. It has successfully colonized 117 of its hosts with the fungus, said Akif Eskalen, a plant pathology researcher at UC Riverside, who has tracked the beetle and confirmed the infestation of Fleming’s tree
While most pests target distressed or dying trees, this one prefers healthy, vigorous hosts, and has spread swiftly through Southern California.
“That just shows how dangerous it is,” Eskalen said. “This beetle can show up any time, anywhere.”
Although there’s no dollar figure for its damage, hundreds of affected street trees in Los Angeles have been removed at a cost of at least $1,000 each, Eskalen said. And that figure is likely to rise, especially if it strikes orchards. In Israel, which has battled the pest since 2009, 40 percent of avocado groves are infested, he said.
Hayne Palmour IV
Share Photo
Just after digging it of his sycamore tree, David Fleming holds a polyphagous shot-hole borer beetle in his palm at his Dehesa Valley home , east of El Cajon, on Saturday.
The beetle originated in South East Asia and appeared in Los Angeles in 2011. It destroyed hundreds of trees at the Los Angeles County Arboretum and Botanic Garden Huntington Botanical Gardens, according to an alert by Los Angeles Supervisor Zev Yaroslavsky, which described the new pest as “tinier than a sesame seed but devastating as poison.”
By 2013, it had spread to Orange County, and in fall, turned up in Fleming’s yard in El Cajon.
Fleming, a golf course architect and superintendent, has spent 40 years designing landscaping for beauty and resilience, selecting a diverse plant palette to hedge his bets against pests.
He planned his own home to showcase the towering, five-trunked sycamore, and carefully nurtured the 100-year-old tree.
In the spring, he added a new fertilizer to encourage its growth and to prevent a common fungus that causes sycamores to shed their leaves. The tree flourished after the treatment, sprouting dense foliage from May through July.
By September, however, it was failing.
“The main trunk of the tree, it just collapsed,” Fleming said.
Fleming contacted Oceanside arborist Tom Launder, who had recently given a presentation to golf course superintendents warning them about the new pest.
“From the photos alone, I saw the staining on the trunk and the dieback symptoms on the leaves didn’t look like anything we see from other pests,” Launder said.
Speak Your Mind