Spotlight Stories
South American Palm Weevil Pest Detected in San Ysidro
The South American Palm Weevil (SAPW), Rhynchophorus palmarum, was recently discovered in a canary island date palm in San Ysidro, southern San Diego County.
Twenty additional canary island date palms in the San Ysidro area appear to be infested, but have not yet been confirmed.
The biology of SAPW is similar to the Red Palm Weevil that was eradicated from Laguna Beach, Orange County in 2010-12. Native to Mexico and Central and South America, the adult of the South American Palm Weevil is approximately 1 ½” long, all black in color, with small hairs on its body. The larvae range from 1-5” long and pupate in a 3” fibrous cocoon.
Rhynchophorus palmarum adult (Photo: T. Ellis) |
Date Palm Debris Showing Signs of Infestation (Photo: Ben DiAnna) |
The SAPW destroys the apical growth of the palm by feeding on the growing tissue in the palm crown, eventually killing the palm, differing from the symptoms of fusarium which causes dying of lower branches. Symptoms of infested palms include yellowing foliage, death of new and emerging fronds, as well as frass at the base of the leaves and pupal cases on the ground near the tree. Holes and tunneling can be found at the base of palm fronds. In addition to canary island date palms, the South American Palm Weevil is also known to attack coconut palms, sago palms, and date palms.
Holes Made by Palm Weevil (Photo: Ben DiAnna) |
Dead canary island date palm from SAPW (Photo: J. Pelham) |
Chipped Canary Island Date Palm to reduce SAPW population. (Photo: L. Taylor) |
Palm Weevil Cacoon (Photo: Ben DiAnna) |
It is believed that the spread of this pest can be delayed with the fast detection and removal of infested trees. Chipping, burning, and burying infested material deeply can reduce the likelihood that Palm Weevil will emerge and escape from infested palms.
To report an infected palm, please call the County Department of Agriculture, Weights & Measures Insect/Bee Hotline at 1-800-200-2337.
Jennifer Pelham, Area Environmental Advisor in San Diego & Orange Counties
Tracy Ellis, Agricultural Entomologist at County of San Diego