UC Riverside scientists test pheromone lure for deadly palm tree pest

UC Riverside (UCR) scientists have a new chemical weapon to seduce and kill the South American palm weevil — an invasive, long-nosed beetle destroying California palm trees by the tens of thousands.

A new $1.1 million grant from the California Department of Pesticide Regulations is enabling project “Fatal Attraction,” which will test a pheromone in urban areas of San Diego County. Weevils there have killed more than 20,000 palms to date.

“A weevil infestation is a death sentence for the palm. These insects have a 100-percent kill rate in three to six months unless the tree is treated very aggressively. Even treatment may not be enough to save an infected palm,” Mark Hoddle, UCR entomologist and director of the Center for Invasive Species Research,

The pheromone Hoddle and his team will test is mixed into a waxy matrix that releases the pheromone slowly so that the treatment lasts for several months, along with a very small amount of insecticide that only kills the pest on contact. The pheromone is species-specific and attracts both male and female weevils. This approach could provide weevil control at much lower costs and reduce the number of insecticides applied.

This treatment represents a more environmentally friendly way to reduce weevil populations than the current strategies, including spraying palm trees with insecticides.

If successful, the treatment would prevent the migration of the weevils toward the Coachella Valley, home to a $100 million date palm industry and only 93 miles from current infestations. According to Hoddle, just a few “super flyers” could enable such an infestation.