Palm Weevils: No Longer a Potential Threat

More or less, in this article I am regurgitating an article I wrote almost exactly a year ago with only minor changes. I've re-titled the article because of the two relatively recent finds in southern California of the two species I warned about last year, the red palm weevil in Laguna Beach and the South American palm weevil in San Diego County next to the Mexican border. Both pose a great threat to our palm producers in southern California and date production in Riverside County. The threat is serious enough that the USDA APHIS is taking it very seriously, and they are poised to issue a Federal Order:  for the red palm weevil and if there is another find of the South American palm weevil, there will be one issued for that pest as well.

There is an informational meeting Wednesday, June 29, 2011, 2:00 PM to 4:00 PM at the County of San Diego Department of Planning and Land Use, Planning Commission Hearing Room, 5201 Ruffin Rd., Ste. B, San Diego. There is a new parking structure for the county offices, so there will be plenty of parking available.

Here is some information about the weevils.

The red palm weevil Rhynchophorus ferrugineus (Olivier) infested palm trees in Egypt beginning in 1992 and the infestation was so extensive that it was responsible for what was considered the greatest loss of palm trees ever encountered in Egypt (Malumphy, C., and H. Moran. 2007. Red palm weevil Rhynchophorus ferrugineus. Central Science Laboratory Plant Pest Notice 5). The insect larvae are described as voracious and often penetrate the crown and most of the trunk of the palm. The tunneling causes weakened trunks, and the trees will fall or if there is enough damage to the crown, they are decapitated. To see photos and movies etc., about the red palm weevil, see this web site: redpalmweevil.com/RPWReport/Egypt.htm

Females weevils live for an average of 170-194 days depending on the host, and can lay approximately 125-184 eggs in lifetime depending on host. Its range has expanded into the Middle East, North Africa, the Mediterranean, and now the Caribbean.

One of the Giant Palm Weevils Rhynchophorus palmarum L. is just as serious a pest of palms as the red palm weevil, but this weevil originates in the tropics of the Western Hemisphere. The giant palm weevil affects both palm plantations and ornamental palms throughout Central and South America and has the potential to extend its range into palm-growing areas of the U.S., hence the reason for adding it to the Federal order mentioned above.

An adult female weevil can live an average of 147.7 days and lay an average of 245 eggs in her lifetime, to a maximum of about 700 eggs. The most serious damage is observed on the following species of palms: Cocos nucifera, Elaeis guineensis, Euterpe edulis, Metroxylon sagu, Phoenix canariensis, Phoenix dactylifera, Saccharum officinarum. The larvae feed in the crown of the palm, often destroying the apical growth area eventually killing the palm.

For more information see the following web sites: http://www.eppo.org/QUARANTINE/insects/Rhynchophorus_palmarum/DS_Rhynchophorus_palmarum.pdf

 http://cisr.ucr.edu/red_palm_weevil.html 

www.cdfa.ca.gov/phpps/rpw/

Unfortunately, this pest is also the main vector of another palm pest, Bursaphelenchus cocophilus (Red Ring Nematode). Giant palm weevil larvae ingest the nematodes while feeding on a nematode-infested palm then transmit the nematode to other palms as they disperse and lay eggs. The distribution of the red ring nematode follows its vector very closely, and the affected countries report palm crop loss of 10-15% or higher due to this nematode.

For more information, see the following web site:

http://edis.ifas.ufl.edu/in392

If you see any of these large weevils, please contact my office or the ag commissioner's office immediately. I would also caution you to be careful when you purchase stock from out of state, to make sure they are palm weevil free. If this pest gets into Florida or California, we will see the landscape here change significantly.

Years ago, the extension specialist at UC Riverside was caring for large palm tree slices (8-12 inches think) that were infested with the Palm Borer, another native, very large beetle that tunnels palm trunks. I remember seeing beetles emerging from those palm slices for long after they were brought to the facility. The palm trees that the slices came from were in the Palm Springs/Indio area. In that area, the numbers were so heavy that they were sweeping the beetles up each morning in the streets. We may face the same fate, if we are not careful.

James A. Bethke

UC Cooperative Extension San Diego

jabethke@ucdavis.edu  

760 752-4715

San Diego County Sheriff's Department

Agriculture Related Crimes from May 15^th through June 20^th, 2011   

Crime Prevention Tips of the Month:

·         Report crimes or suspicious activity immediately to Sheriff's Dispatch 24/7/365         

·         Call Sheriff's Dispatch Center 1^st to report suspicious activities, crimes in progress or crimes that have occurred

·         Call surrounding neighbors/businesses 2^nd to advise them to be on the lookout for unknown persons or vehicles in the area and ask if they saw anything that may be helpful to identify any suspects related to crimes that occurred.

·         Call B.J.   3^rd to advise what actions were taken thus far and schedule a FREE Security Consultation for your property to discuss the crime and crime deterrence measures

·         Report unscrupulous vendors trying to sell product, fuel, or equipment at drastically reduced prices

·         Establish a Nursery/Grove/Farm Watch in your area - B.J. will assist you in that effort