Bursaphelenchus cocophilus
(Radinaphelenchus cocophilus)
Cobb, 1919
Red Ring Nematode
Red ring nematode, Bursaphelenchus cocophilus, causes the Red ring disease of palms and is a very important palm pest in the Neotropics. Bursaphelenchus cocophilus parasitizes the palm weevil, Rynchophorus palmarum L. which transmits it to the coconut palm  and the oil palm.

Life cycle
Adult female weevils which are internally infested with B. cocophilus disperse to a healthy coconut palm and deposit the juvenile stage of the nematode during oviposition.  Nematodes enter the wounds, feed, and reproduce in the palm tissues, causing the death of the infected trees.  The weevil larvae are parasitized by juveniles of B. cocophilus which persist in the insect through metamorphosis and appear to aggregate around the genital capsule of the adult weevil. The adult weevils emerge from their cocoons in the rotted palm and disperse to apparently healthy or stressed and dying palms, completeing the life cycle

Geographic distribution and dissemination
B. cocophilus infects coconut palms in many areas of South and Central America, Mexico, and the Carribean. The nematodes  principally reach noninfected palm trees in or on the bodies or feces of the palm weevil. They also may be carried on seeds, seedlings, tools, vehicles, animals, or move by natural migration from infected to noninfected roots.  Wood chippings from axes or machetes used to fell infected palms, as well as the felled infected palms themsevles also serve as infective material. B. cocophilus does not survive in soil for more than 2-3 days, but it lives in decomposing tissue of dead palms up to 90 days.  Inside its weevil vector, B. cocophilus can survive 10 days, while on the body ot its vector, it can survive only 2-3 daysLive B. cocophilus have been recovered from decaying roots a year after removal of the top portion of the palm.

Habitat
Highest incidence of Red ring disease caused by B. cocophilus occurs in low, poorly drained areas.  B. cocophilus are susceptible to desiccation, and drought conditions keep the disease in check. B. cocophilus survive best in wet, swampy areas, in clay rather than sandy soil.

Regulatory considerations
B. cocophilus causes serious damage to coconut palms in the Neotropic region and also in Brazil where it is vectored by the weevil Rhincophorus palmarum.  The nematode can be introduced with infected weevils or infected coconut palm material.  If introduced into the United States this pest may be vectored by native Rhincophorus species.  This nematode poses a great risk to the ornamental palm industry of the U.S.

Information taken from Florida Dept. of Agriculture and Consumer Service, Plant Industry Div.
Nematology Circulars # 181 and 141, Sept. 1990 and May 1987.
To order copies of these or other circulars, contact them at: http://doacs.state.fl.us/