A third quarantine area has been established in San Diego County for the Diaprepes Root Weevil. The California Department of Food and Agriculture (CDFA) has established a 3-square-mile quarantine for the weevil in the La Costa area of Carlsbad. This pest has been discovered on a variety of ornamental plants in the area.

All nursery stock, plants, plant parts and products, soil, sand, gravel, growing mediums, and dying or dead plant material are subject to restrictions on movement in and out of the quarantine area. A similar quarantine was established in May in the University City area of San Diego and June in the Olivenhain area of Encinitas. CDFA is working with the San Diego County office of Agriculture, Weights & Measures (AWM) to evaluate the best options for management of these weevil populations.

In an effort to quickly detect any additional infested sites, CDFA has distributed posters and fliers to nurseries and other sites in and near the quarantine areas in San Diego, Los Angeles and Orange counties. The next step will be to send postcards with photographs and descriptions of the pest to residents in other areas of the state.

Homeowners are asked to contact a CDFA Hotline at 1-800-491-1899 before moving any plants, soil or related garden or landscape materials out of the quarantine areas. Residents are also encouraged to use the hotline to report suspect insects. Adult weevils are about three-quarters of an inch in length, with markings on their backs ranging from black and orange to cream colored.

The public’s cooperation in implementing this quarantine is greatly appreciated. The pest threatens more than 270 plant species including many landscaping plants. Left unchecked, the root weevil infestations could also impact the nursery industry and damage a wide range of California’s agricultural crops.

Diaprepes root weevils are native to the Caribbean. The pest has generally infested Florida and has also infested a part of Texas. Adult weevils feed on the leaves of plants, and their larvae plunge underground and feed on plant roots. The larvae can encircle or “girdle” the root systems of trees, cutting off the supply of water and nutrients and eventually killing the host plant.

For more information, please go to http://www.cdfa.ca.gov/phpps/pdfs/Diaprepes.pdf or San Diego County’s Web page www.sdcawm.org.