Abstract
The problem of plant diseases occupies a prominent place in the axes of agronomic research in many countries, especially developing ones, where agriculture is generally the engine of the economy. Despite extensive agronomic research, there is a good deal of crop production which until now seemed to be neglected such as cassava (Manihot esculenta). This culture nowadays occupies the front of a lot of research given its strengths as one of the avenues for convincing solutions to the two major challenges (climate change and food security) in southern countries such as Mali. However, it faces a major parasitic constraint, the vascular bacteriosis of cassava (CBB, for Cassava Bacterial Blight) caused by the gram-negative bacterium Xanthomonas phaseoli pv manihotis (Xpm).In Mali in order to offer a source of diversification to conventional food crops largely dominated by cereals and to promote crops resilient to the effects of climate change, we carried out a socio-agronomic and phytoparasitic study on cassava. This is how we focused on: (i) the socio-economic characteristics of cassava production in 05 of the most important cassava-producing regions; (ii) the biological and genetic knowledge of Xpm on cassava in Mali and elsewhere in Africa (Nigeria and Cameroon) and (iii) the resistance to Xpm of local varieties of cassava widely produced in Mali.A series of survey and prospecting followed by field sampling in Mali, but also in Nigeria and Cameroon have enabled us to collect epidemiological data and obtain a range of plant material symptomatic of CBB. With these data we had better sharpened our reflections and arguments on the use of samples: isolation, bio-molecular characterization, pathogenicity test, MLVA analysis of genetic diversity, varietal screening.Our results denote the presence of CBB in the 03 countries surveyed and specifically allow confirmation of the disease presence status (CBB) in Mali. In this country, the production system remains very vulnerable to pests, dominated by a family approach with a small area (from 0.15 to 2 ha in general) with a long-year use of the same varieties, a majority use of the hand of family work and also exchanges of cuttings between producers from the same village who are in the majority (78% of cases of acquisition of cuttings). The study of the diversity and structure of xpm populations in Mali allows us to assume an endemic presence of the disease in Mali. As for the local varieties cultivated in Mali, they are for the most part sensitive to the most present strains (according to the analysis of the family tree from the MLVA analysis.