The Coastal Gardener: United effort needed to protect iconic tree

In the past three weeks, a 1.5-inch beetle has caused a flurry of activity among county, state and federal officials. Local palm enthusiasts have begun to panic. Landscape professionals, responsible for the health of the region’s palms, are worried.

The Red Palm Weevil, the most destructive pest to palm trees, was recently discovered in northern Laguna Beach — the first time it’s been seen in the United States. If this exotic pest establishes itself in California, the damage to date palms, both in landscapes and agriculturally, would likely be irreversible. In only a few years more than 100,000 Phoenix date palms have been destroyed in southern Europe. Many more are doomed, and the equivalent of more than 140 million Euros have been spent to little effect.

Monitoring efforts soon began after the discovery.

A visual survey was conducted by Don Hodel, an environmental horticulturist with the University of California Cooperative Extension and one of the country’s leading palm specialists, and Nick Nisson, Orange County’s entomologist. None were found.

Staff with the state Department of Food and Agriculture have placed about 250 traps throughout a nine-square-mile area. The traps are specifically designed to attract and hold Red Palm Weevils. In addition, door-to-door surveys are being performed by Food and Argriculture inspectors. The surveyors have inspected 86% of the properties in a 1.5-square-mile area around the “hot zone”; 1,481 properties and 9,721 palms have been surveyed.

By Monday, no Red Palm Weevils had been seen or captured.

But bad news arrived via e-mail Tuesday night from Dr. Mark Hoddle, director of invasive pest studies at UC Riverside’s Center for Invasive Species Research. Another dying Canary Island Date Palm was found just blocks from the initial infestation. This second infested Laguna Beach palm was heavily damaged and near death.

“The crown of the palm has dropped off, and the top of the trunk is now ringed with a ‘halo’ of palm fronds,” Hoddle wrote. “The trunk of the palm has been heavily damaged internally by feeding Red Palm Weevils. The central portion of the trunk now contains a highly fermented and very wet ‘mash’ of plant material.”

Portions of at least nine dead adult weevils, one live adult and seven empty pupal cases, were discovered at the site of the dying tree, which to date has still not been removed. Additional weevils may still be present within the dying tree.

It is now likely that additional palms in North Laguna are infested with this destructive pest.

County, state and federal officials are working swiftly to assemble strategies. An informational meeting has been called for next week in Laguna Beach to inform local government officials, arborists, public works, landscapers and pest control advisors about the current Red Palm Beetle situation, including properly identifying the pest and its feeding damage. Future meetings will target other groups, including the public. I will keep you posted.

In the meantime, what can you do? Learn more about this pest, so that misinformation is not spread and improper reactions do not ensue. Hoddle and his colleagues have created an excellent website and blog with updates at https://cisr.ucr.edu/red_palm_weevil.html. Also visit https://www.cdfa.ca.gov/phpps/rpw/ for additional information and photos.

After learning to recognize at least the advanced symptoms of palms infested with Red Palm Weevils, report any suspicious plants, along with details to Food and Agriculture’s pest hotline at (800) 491-1899.

If government experts, local communities, landscape professionals and concerned citizens work together, in an integrated manner, we may be able to eradicate this destructive pest before it advances further. Working together and intelligently, we may be able to save California’s majestic and iconic date palms.

RON VANDERHOFF is the Nursery Manager at Roger’s Gardens, Corona del Mar.