Discovery of new diseases of cassava in West Africa. (58)

Authors

  • W. Msikita International Institute of Tropical Agriculture, Biocontrol Center for Africa, 08 B.P. 0932 Tri Postal, Cotonou, Benin, West Africa
  • B. James International Institute of Tropical Agriculture, Biocontrol Center for Africa, 08 B.P. 0932 Tri Postal, Cotonou, Benin, West Africa
  • M. Ahounou International Institute of Tropical Agriculture, Biocontrol Center for Africa, 08 B.P. 0932 Tri Postal, Cotonou, Benin, West Africa
  • H. Baimey International Institute of Tropical Agriculture, Biocontrol Center for Africa, 08 B.P. 0932 Tri Postal, Cotonou, Benin, West Africa
  • B.G. Facho International Institute of Tropical Agriculture, Biocontrol Center for Africa, 08 B.P. 0932 Tri Postal, Cotonou, Benin, West Africa
  • R. Fagbemissi International Institute of Tropical Agriculture, Biocontrol Center for Africa, 08 B.P. 0932 Tri Postal, Cotonou, Benin, West Africa

Keywords:

Cassava, Curvularia lunata, Nattrassia mangiferae, Growth reduction, West Africa

Abstract

Two new diseases of cassava were discovered in Benin, Ghana, and Nigeria. Curvularia leaf and stem blight [Curvularia lunata (Wakker) Boedijn) was discovered in all three countries. In the field incidence of Curvularia-infected plants ranged between 0 and 80%, and severity between 2 and 25 lesions per plant. The effect of the fungus on growth was investigated using six cultivars, all naturally infected. For all cultivars, when buds were completely colonized, sprouting was completely inhibited. However, partially colonized buds sprouted, but growth was reduced by 20-50% (depending on genotype), compared with healthy stems. On artificially inoculated leaves, C. lunata induced lesions of up to 1.5 cm and 40% leaf abscission, compared with healthy leaves. Nattrassia mangiferae (Syd. & P. Syd.) B. Sutton & Dyko root and stem rot was discovered in Benin and Nigeria, with field incidence ranging between 0 and 54%. For all four cultivars, N. mangiferae significantly reduced the number of shoots, shoot growth, and number of roots. Two of the cultivars died three weeks after planting.

Issue

Section

Research Papers