BANANA DISEASES IN THE SUBTROPICS: A REVIEW OF THEIR IMPORTANCE, DISTRIBUTION AND MANAGEMENT
Other important diseases of the plant are usually not fatal, but can limit production severely. Of these banana bunchy top, caused by the banana bunchy top virus, is the most destructive. Fortunately, it has a somewhat restricted geographic distribution, and can be controlled by frequent rouging of affected plants. The spiral nematode, Helicotylenchus multicynctus, a minor pest in the tropics, is the most serious of the nematodes in the subtropics. Although regulatory practices have made nematicides unavailable in many countries, hot water treatment of rhizomes is effective.
The most important leaf diseases are yellow Sigatoka (Mycosphaerella musicola) and freckle (Guignardia musae). These and other foliar diseases can be serious during periods of high rainfall, but can be controlled with protectant and systemic fungicides and plantation sanitation.
Several different diseases reduce the quality and post-harvest life of fruit. The most important of these include anthracnose (Colletotrichum musae), cigar-end rot (Trachysphaeria fructigena and Verticillium theobromae), crown rot (Ceratocystis paradoxa, C. musae, Fusarium pallidoroseum, Lasiodiplodia theobromae and V. theobromae), finger rot (L. theobromae), Johnson spot (Magnaporthe grisea) and squirter disease (Nigrospora sphaerica). As for the leaf diseases, plantation sanitation and fungicide treatments are indicated.
Future prospects for managing these diseases are discussed in light of restrictions on pesticide use, new pesticides that are being developed, and the use of resistant genotypes. Conventional breeding of this important crop is also discussed, since new hybrids will become increasingly important in the future.