Bursaphelenchus cocophilus

The red ring disease of coconuts and African oil palms is caused by the nematode Bursaphelenchus cocophilus . It is also identified in literature with an alternative scientific name Rhadinaphelenchus cocophilus . The common name, the red ring nematode, is derived from its distinguishing symptom.

Significance

This nematode can cause losses up to 80%, however, the losses typically range from 10-15% to coconut palms and oil palms. [1]

Distribution

This nematode is distributed in Central and South America, and some of the islands in the Caribbean. [2]

Identification

The distinguishing characteristics of this method are well-developed metacorpus from J2 to adult, a short stylet 11-15 μm in adults, typically 1mm in length. Females have the vulva located two-thirds body length and have a vulval flap. Females have a long post uterine sac and a rounded tail. Males have seven papillae in the tail region, distinct spicules, and bursa shaped as a spade. [3]

Life cycle

The red ring has a typical parasitic life cycle, having 4 molts before becoming an adult. The whole life cycle lasts approximately ten days. The survival stage is the J3. [4] The dissemination of this nematode depends on its relationship with its vector.

Insect vector relationship

The vector, Rhynchophorus palmarum (South American palm weevil), carries the J3 stage to healthy palms. Female weevils are internally infested around the oviducts, when they lay their eggs in the palm they also disseminate the nematode. [5]

Host-parasite relationship

The symptoms produced by this nematode are chlorosis beginning in the oldest leaves and a distinct red / brownish ring in the trunk of the tree.

Management

To manage this disease scouting is the most important aspect; early detection of infected trees may save plantations. If an infected tree is found it must be removed, treated with herbicide and cut down. Leaving the stump behind can lead to vector reproduction and spread the nematode. Trapping the vector is another strategy, reducing the incidence incidence from 10% to 1%. [6]

Footnotes

  1. Jump up^ Esser and Meredith 1987
  2. Jump up^ CAB 1999
  3. Jump up^ Goodey 1960
  4. Jump up^ Blair and Darling 1968
  5. Jump up^ Chinchilla 1991
  6. Jump up^ Oehlschlager 2002

References

  • Blair, G. and Darling, D. (1968). Red ring disease on coconut palm, inoculation studies and histopathology. Nematologica 14: 395-403.
  • CABI / EPPO (1999). Rhadinaphelenchus cocophilus . Distribution Maps of Plant Diseases No. 786. CAB INTERNATIONAL. Wallingford, UK.
  • Chinchilla CM. (1991). The red ring little leaf syndrome in oil palm and coconut palm. ASD Oil Palm Papers No. 1, 1-17. http://www.asd-cr.com/ASD-Pub/Bol01/b01c1.htm (21 June 2009).
  • Esser, RP and JA Meredith (1987). Red ring nematode. Fla. Dept. Agric. & Consumer Serv., Div. Plant Ind., Nema. Circ. No. 141.
  • Goodey, J Basil (1960). Rhadinaphelenchus cocophilus (Cobb, 1919) N. Comb., The nematode associated with “red-ring” disease of coconut. Nematologica 5: 98-102.
  • Oehlschlager, AC, Chinchilla, Carlos, Castillo, Geovani, and Gonzalez, Lilliana (2002). Control of Red Ring Disease by Mass Trapping of Rhynchophorus palmarum (Coleoptera: Curculionidae). The Florida Entomologist 85 (3): 507-513.