South American Palm Weevil Makes Headway into California

Brian GermanPest Update

The South American palm weevil has been killing Canary Island date palms in Tijuana and Baja California for the past seven years.  The pest has migrated into California as more attractive food sources become available due to the changing desert landscape.

Courtesy: UC ANR

Mark Hoddle is a Biological Control Specialist and Principal Investigator in the Applied Biological Control Research laboratory at UC Riverside.  “Humans have created this ideal environment throughout these desert areas by urbanization, planting palm trees and keeping them really well irrigated,” said Hoddle.

The weevil is a relatively large pest and a single tree can house up to 1,000 weevils at a time.  One particular concern is their capability of flying long distances.  “We’ve been doing some experiments to figure out how far they can fly and we don’t think it’s impossible for the weevil to fly about 15 miles a day if it wanted to,” stated Hoddle.

Sightings of the South American palm weevil in California first began around 2011 in San Diego County.  The pest has made its way up to Chula Vista and could already be even further north.  “That’s our major worry is that this weevil will get into the date production areas in the Coachella Valley.  It has the potential to be a significant problem for the date producers,” Hoddle said.

California is responsible for 90% of the country’s date production.  Growers produced 43,600 tons of dates valued at $68 million dollars in 2015 and date production has continued to expand since then.  “The demand for dates as a healthy, nutritious food is increasing and people like California dates,” Hoddle stated.

The best management strategy is going to rely heavily on early detection, so it’s important to keep an eye out for the South American palm weevil.  So far commercial date producing trees have not been affected, but Hoddle believes that it’s better to be aware of the potential problem before it becomes a major issue.