Scientists and growers recently met at the University of California, Riverside to address a potentially devastating new threat to California’s iconic palm trees, the red palm weevil.
Confirmation was received that the red palm weevil, considered the world’s most damaging insect pest of palm trees, was found in Laguna Beach in Orange County, Calif.
The weevil was discovered infesting a Canary Islands palm in a residential area in September 2010.
The insect was subsequently positively identified as Rhynchophorus ferrugineus, the red palm weevil, by experts at the USDA-Agricultural Research Service Systematic Entomology Laboratory in Maryland.
Weevil larvae bore tunnels through palm trunks during feeding eventually killing the trees.
Thomas Baldwin, dean, UC, Riverside’s College of Natural and Agricultural Sciences, and Albert Keck, chair, California Date Commission and a Coachella Valley palm grower, convened the meeting to plan strategies for containing and eradicating the weevil which has caused enormous damage elsewhere in the world.
The Orange County sighting is the first appearance of the weevil in the United States.
Keck, president of Hadley, Inc., which supplies dates to the food industry and palm trees to the landscape industry, said, “This problem is central to our livelihood.”
Noting that palm trees are an integral part of the Southern California landscape, Keck said the potential impact of the weevil on the state and beyond would be catastrophic.
The university is preparing a proposal to collaborate with the California Department of Food and Agriculture to manage the weevil and the threat it poses to the public and industry. An informational campaign is planned to alert and educate homeowners.
A follow-up meeting is planned Oct. 29 at UC, Riverside.
Entomologist Mark Hoddle, director, Center for Invasive Species Research, UC, Riverside, said, “The international trade in live palms is the most likely source for this pest. It was probably moved as eggs, larvae, or pupae hidden inside palms. These can travel great distances because they live with their food supply.”
Once larvae emerge as new adults, the adults abandon the original host plant and fly to new palms; capable of traveling about 4.3 miles in three to five days.
Adult red palm weevils are large beetles with body lengths of 1.4 to 1.6 inches. The weevils have a long, slender “snout” which the female uses to penetrate palm tissue and create access wounds where eggs are deposited. Adult weevils are predominately reddish-brown in the most typical form.
The weevil collected in Laguna Beach has a single, contrasting red stripe running the length of the snout. The larvae are legless grubs and pale yellow with a brown head. Some are larger than 2 inches.
“A strong message needs to go out as soon as possible to arborists and others in industry to keep an eye out for this deadly pest,” Baldwin said. “Unlike many previous agricultural pests, the red palm weevil is also an urban problem. We at the university have two ways to proceed: we assume the pest has already spread or we wait to see signs of it having spread. We are not willing to wait.”
For more information, visit http://cisr.ucr.edu/red_palm_weevil.html.