Cocopest - Information portal for major pests and diseases of coconut
Cocopest - Information portal for major pests and diseases of coconut
Cocopest - Information portal for major pests and diseases of coconut
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Candidatus Phytoplasma palmae (Lethal Yellowing)
General information
Phytoplasmas are associated with many serious diseases of coconut including lethal yellowing- like diseases (LYDs) [1]. Candidatus Phytoplasma palmae is one of the LYDs which is reported to attack 37 species of palms. It is highly destructive and has destroyed a majority of the coconut palms on the Caribbean coast since the 1980s. In Florida, the LYD has also infected the ornamental palms [2]. LYDs are potential threats to the coconut production and yield losses can be significant [3].

The International Board for Plant Genetic Resources (IBPGR) has developed a technical guideline to avoid spread of LYDs by introducing safe movement of plant materials between areas [4].

LYD symptoms are similar in different parts of the world but the progression of symptoms and the susceptibility of different varieties can vary [1]. The typical development of symptoms can help to identify LYD and distinguish it from other diseases [5].

Symptoms observed in mature palms include [3]:

  • Early nutfall
  • Calyx end of the fallen nuts are observed to be blackened or water-soaked
  • Necrosis of newly emerging inflorescences
  • The flower spikelets usually blackened
  • Foliar discoloration
  • Unopened leaves fall off
  • Crown withers
Detection and Inspection
The palms can be infected for several months before symptoms appear [3, 5]. Visual observation of symptoms is not adequate to diagnose infection. Molecular identification is required to confirm infection (PCR and LAMP).
Taxonomic information
Category - Bacteria
Domain - Bacteria
Phylum - Firmicutes
Class - Mollicutes
Order - Acholeplasmatales
Family - Acholeplasmataceae
Genus - Candidatus Phytoplasma
Species - palmae
Common Name - Lethal Yellowing
Scientific Name - Candidatus Phytoplasma palmae
LYD has been reported in Florida (US); Central America and Caribbean (Antigua, Bahamas, Belize, Cayman Islands, Cuba, Dominican Republic, Guatemala, Haiti, Honduras, Jamaica, Mexico, St. Kitts & Nevis) [1].
Prevention and Control
  • Eradication of infected palms in areas of susceptible germplasm in newly infected areas [3].
  • Planting of groundcover crops can reduce the reproductive potential of insect vector H. crudus [3] (e.g. tropical forage grasses such as Brachiara brizantha, Chloris gayana or Hemarthria altissima).
  • The use of insecticides helps to reduce the vector population [13].
Plant Parts Affected
Flower, Nut
  1. Gurr, G.M., Johnson, A.C., Ash, G.J., Wilson B.A. L., Ero, M.M., Pilotti, C.A., Dewhurst, C.F. & You, M.S. (2016). Coconut Lethal Yellowing Diseases: A Phytoplasma threat to palms of global economic and social significance. Frontiers Plant Sci, 7(1521).
  2. CABI CPC (2019a). Datasheet on Haplaxius crudus (American palm cixiid). Retrieved from
  3. CABI CPC (2019b). Datasheet on Candidatus Phytoplasma palmae. Retrieved from
  4. Frison, E.A, Putter, C.A.J. & Diekmann, M. eds. (1993). FAO/IBPGR technical guidelines for the safe movement of coconut germplasm. Rome, Italy: FAO/IBPGR, 48 pp.
  5. Sullivan, M. & Harrison, N. (2013). CPHST Pest Datasheet for ‘Candidatus Phytoplasma palmae’ and related strains. USDA-APHIS-PPQ-CPHST.
  6. Howard, F.W. (1981). Pigment migration in the eye of Myndus crudus (Homoptera: Cixiidae) and its relation to day and night activity. Insect Sci Appl, 2 (3):129-133.
  7. Howard, F.W., Wilson, M.R. (2001). Hemiptera: Auchenorrhyncha. In F.W. Howard, D. Moore, R.M. Giblin-Davis & R.G. Abad (eds.), Insects on Palms (pp. 128-160). Wallingford, UK: CABI Publishing.
  8. Molet, T. (2013). CPHST pest datasheet for Haplaxius crudus. USDA-APHIS-PPQ-CPHST.
  9. EPPO/CABI (1997). Palm lethal yellowing phytoplasma. In I. Smith, D. McNamara, P. Scott & M. Holderness (eds.), Quarantine Pests for Europe (pp. 745-748). Wallingford, UK: CABI Publishing.
  10. Woodiel, N.L. & Tsai, J.H. (1978). A rotary flight trap used for sampling Haplaxius crudus (Homoptera: Cixiidae) in coconut groves. JNY Entomol Soc, 86 (1):37-44.
  11. Harrison, N.A. & Elliott, M.L. (2008). Lethal Yellowing of Palms. Plant Health Instr, 714 (1).
  12. Harries, H.C. (1978). The evolution, dissemination and classification of Cocos nucifera. Bot Rev, 44, 265-320.
  13. Anon (unknown). Caribbean Plant Health Directors: Priority pest threats to the region - Lethal Yellowing of Coconut.
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