DISEASES AND OTHER BANANA HEALTH PROBLEMS IN TROPICAL AFRICA

Yield is the overall indicator of banana health. Agronomic traits of cultivars and soil fertility are the major yield determinants followed by resistance to diseases. Of the diseases, nematode root rot and fungal defoliators are the most important. The major defoliators are Mycosphaerella fijiensis and Cladosporium musae. The Cosmopolites weevil reduces yield in some areas. Vast efforts have been devoted to evaluating weevil damage by trapping and measuring percentage coefficient of infestation. However, there are no data showing a correlation with yield loss. At present, snap-off is the only reliable indicator of serious weevil damage. Nematode root rot causes uprooting and lower bunch weight. No studies have been undertaken on bunch weight with the exception of export bananas and plantains. Because of an association between nematode root rot and weevils, weevil studies are needed with plants free of root rot. A team approach with agronomists, soil specialists, entomologists and plant pathologists is needed to sort out yield determinants in different ecological zones. In the long term, breeding will resolve some of the present yield detractants. As yet, bred cultivars have had no significant effect on increased productivity.