Gibberella xylarioides

Gibberella xylarioides (Fusarium xylarioides) is a species of fungus in the family Nectriaceae. It is the causative agent of coffee wilt disease (CWD). The disease caused a severe problem in several countries in West and East Africa during the 1940s and 1950s.[1] CWD was first seen in Coffea liberica.[2]

Gibberella xylarioides
Scientific classification
Kingdom:
Fungi
Division:
Ascomycota
Class:
Sordariomycetes
Order:
Hypocreales
Family:
Nectriaceae
Genus:
Gibberella
Species:
G. xylarioides
Binomial name
Gibberella xylarioides
R. Heim & Saccas, (1950)
Synonyms

Fusarium oxysporum f. xylarioides (Steyaert) Delassus, (1954)
Fusarium xylarioides Steyaert, (1948)

Hosts

Main hosts

Coffea arabica (arabica coffee)

Coffea canephora (robusta coffee)

Coffea liberica (Liberian coffee tree)

Other Hosts

Gossypium (cotton)

Musa x paradisiaca (plantain)[1]

Signs and symptoms

Similar to other vascular wilt pathogens, the fungus colonizes the xylem and causes the flow of water to be cut off. It can be diagnosed by several visual signs. The leaves can wilt, have vein necrosis, and abscission. The coffee bark, when scraped with a knife, will have a blue-black coloration. The berries will appear as though they are ripening prematurely but will stay on the coffee plant after the leaves have fallen off.[3] Necrosis can often be seen near the collar of the plant.[4]

Young trees can be killed within a few days of infection while more mature coffee plants can survive up to 8 months.[2]

Gibberella xylarioides (Sexual form) will make purple perithecia and ascospores, but resting structures are rarely found in the soil. Fusarium xylarioides (Asexual form) make sickle shaped conidia and are spread by wind, rain, and human activities like weeding and harvesting.

Management

Other methods of management include:

  • Removal of diseased trees and burning is the most successful method of eradication of Coffee Wilt.[5] Coffea sp. should not be replanted in soil for six months to avoid infection of seedlings.
  • Care when weeding around coffee plants to avoid injuring the bark as the fungus can enter the bark through wounds
  • Using planting tools that are free of disease
  • Spraying the soil surface with 2.5% copper (II) sulphate[3]
  • Breeding resistance—"The results of greenhouse inoculation experiments proved that there was important diversity in coffee populations (within and among the forest sites) in reaction to G. xylariodies infection."
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References
  1. "Gibberella xylarioides (coffee wilt)". www.cabi.org. Retrieved 2017-10-26.
  2. M., Waller, J. (2007). Coffee pests, diseases and their management. Bigger, M., Hillocks, R. J. Wallingford, UK: CABI Pub. ISBN 9781845931292. OCLC 567837010.
  3. Coffee wilt disease. Flood, J. (Julie). Wallingford, UK: CABI. 2009. ISBN 978-1845937355. OCLC 609863641.CS1 maint: others (link)
  4. Paul., Holliday (1995). Fungus diseases of tropical crops (Dover ed.). New York: Dover Publications. ISBN 0486686477. OCLC 31970561.
  5. Musebe, R. O.; Njuki, J.; Mdemu, S.; Lukwago, G.; Shibru, A.; Saiba, T. (2010). "Socio-economic impact of coffee wilt disease.". Coffee wilt disease. pp. 83–98. doi:10.1079/9781845936419.0083. ISBN 9781845936419.


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