Comparison of Development of Mycosphaerella fijiensis and Mycosphaerella musicola on Banana and Plantain in the Various Ecological Zones in >Cameroon. A. Mouliom-Pefoura, Research Plant Pathologist, Centre de Recherches Regionales sur Bananiers et Plantains (CRBP), Box 832 Douala, Cameroon. A. Lassoudiere, Agronomist, Cirad-Flhor, box 5035 - 34032 Montpellier, France; and J. Foko and D. A. Fontem, Plant Pathologists, University of Dschang, Box 110 Dschang, Cameroon. Plant Dis. 80:950-954. Accepted for publication 16 March 1996. Copyright 1996 The American Phytopathological Society. DOI: 10.1094/PD-80-0950.

Mycosphaerella fijiensis (black leaf streak disease) has replaced M. musicola (yellow Sigatoka disease) as the primary pathogen of banana and plantain in many of the low (0 to 500 m) and mid (500 to 1,000 m) elevations, but does not yet exist in the highland (> 1,300 m) banana- and plantain-producing areas of Cameroon. Host-pathogen relationships of the two diseases were evaluated in the three ecological zones of Cameroon during 1993 and 1994 by experimental inoculations. In the low altitude zone (80 m), the first phases of parasitic infection (conidial germination, growth of germ tubes, and incubation period) were identical for both M. fijiensis and M. musicola. However, the duration of lesion expansion at low altitudes was shorter for M. fijiensis than for M. musicola, which may help explain the disappearance of the latter pathogen in the lowland areas. In the mid-altitude (900 m) and high-altitude (1,350 m) zones, conidia of M. musicola developed faster than those of M. fijiensis. The incubation period was also shorter for yellow Sigatoka disease(17 to 20 days) than for black leaf streak disease (22 to 24 days); however, black leaf streak disease could develop in these zones. These results should be taken into consideration in production strategies of bananas and plantains, especially when transferring planting materials between different ecological zones.