Varietal reactions of bananas and plantains to black leaf streak disease

• Chapter Authors : Fouré, E.


• Document type : Conference paper


• Year of publication : 1987


• Book title : Banana and plantain breeding strategies: ACIAR Proceedings No. 21


• Editors : Persley, G.J.; De Langhe, E.A.L.


• Pages : 110-113


• Language(s) : English


• Abstract : Sigatoka diseases in bananas and plantains are caused by Mycosphaerella musicola, the agent of Yellow Sigatoka, and by Mycosphaerella fijiensis, the agent of Black Sigatoka or black leaf streak disease. These two diseases are the most important diseases of banana, and may cause the total collapse of the plant, in highly susceptible varieties. The initial symptoms are foliar leaf streaks, with consequent reduction in photosynthetic leaf surface. This results in a loss in gross yield at harvest time and in the premature ripening of the fruit on the trunk, which prevents the marketing of the crop with a consequent net yield loss in exportable tonnage. M. musicola (Yellow Sigatoka) attacks bananas but not plantains. However, M. fijiensis attacks both bananas and plantains. Plantains are a staple food in many West African countries. Black Sigatoka appeared only recently in Africa. It was identified in Gabon in 1980; the neighbouring countries (the Congo, Equatorial Guinea and Cameroon) are also now affected by the disease, which is rapidly replacing Yellow Sigatoka. Black Sigatoka has also been reported recently in the Ivory Coast and in Nigeria in the Port Harcourt area. A research program to study the pathogenic activity of the fungus was established in Galion in 1981. Its aim has been to develop improved methods to control the disease and to become better acquainted with the biology and epidemiology of the fungus. Such a program has also been undertaken in Cameroon since November 1985. The research conducted in Africa into M. fijiensis has benefited from the work undertaken for many years by IRFA on M. musicola. In our investigation into the biology of the Black Sigatoka pathogen and into the evolution of the disease, we used previous research and are now able to launch a systemic control program for the disease as soon as notification reaches us of new outbreaks. Although encouraging results have been obtained in our research into chemical control, it seems that the genetic approach is the only control strategy that allows the maintenance of production levels in the long term. Genetic improvement is now given priority in research, with the aim of finding varieties, which are resistant or tolerant to Black Sigatoka. We have studied under conditions of high incidence of Black Sigatoka the behaviour of cultivars belonging to the diploid (AA) and triploid (AAA) acuminata groups, and the hybrid triploids AAB and ABB. We have also completed our studies on phases of incubation and development of the disease along the following parameters: morphological traits of asexual and sexual phasessrzs intensity of speculation; study of the lateral transportation of ascosporessrzs and distribution of symptoms on the plant. The evolutionary cycle of M. fijiensis comprises, as in the case of all other parasites, two distinct phases: 1) dispersion and establishment, followed by 2) development of the interaction with the host. (Author's abstract).


• Keywords : MYCOSPHAERELLA MUSICOLA; DISEASE RESISTANCE; MYCOSPHAERELLA FIJIENSIS; DISEASE CONTROL; VARIETIES; SYMPTOMS; CHROMOSOME NUMBER; HOST-PATHOGEN INTERACTIONS; DEFENCE MECHANISMS; GEOGRAPHICAL DISTRIBUTION; AFRICA


• Open access : Yes


• Document on publisher's site : View article on publisher's site


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• Musalit document ID : IN090184

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