RSF Association to host Jan. 25 talk on weevil attack of palm trees

A palm weevil-infested tree in Rancho Santa Fe.
(Sally Koblinsky)

Throughout Southern California, palm trees have fallen victim to the South American palm weevil infestation, once stately skyline trees sadly dropping into a frown. The weevils have killed an estimated 20,000 ornamental and date palm trees in San Diego County, including hundreds of Canary Island date palms in Rancho Santa Fe.

An iconic community feature, the palm trees are among the most common in the Covenant with an estimated 16,500 palms on residential properties, the golf course and public areas according to the Rancho Santa Fe Association’s 2018 Forest Health Study.

“Without a doubt, this is the worst palm pest California has ever dealt with. Once these weevils get into a palm tree, they lay eggs in the palm, and those eggs hatch into these really large larvae which destroy the palm heart,” said Dr. Mark Hoddle, biological control specialist and principal investigator at the Center for Invasive Species Research at University of California Riverside. “The first sign of infestation is seeing the crown droop and turn brown. The tree can’t grow any new fronds and all you are left with is a halo of dying fronds…. It’s basically a death sentence for a palm tree.”

In response to residents’ growing concerns over the loss of trees, the Association and Forest Health and Preservation Committee have invited Hoddle to provide an informative presentation to the community on Wednesday, Jan. 25 at 5:30 p.m. at the Rancho Santa Fe Golf Club.

At UC Riverside, Hoddle has studied the South American Palm Weevil for seven years and is a leading researcher of this pest.

His one-hour talk will cover South American weevil biology, its spread and damage, trapping and insecticide treatments, palm removal and management of infected palm material. He will also describe a new approach to lure and kill the invasive pest.

With a recent million-dollar grant from the California Department of Pesticide Regulations, Hoddle is testing an environmentally-friendly, less expensive method for reducing the weevil populations than the current insecticide applications to palm foliage and soil. His grant also provides an opportunity for select communities to participate in the research.