Major Leaf Diseases and Pathogenicity of Fungal Flora Associated with Jatropha curcas L. Foliar Diseases in Burkina Faso

Abstract

The major foliar diseases and pathogenicity of fungal flora associated with leaf diseases of Jatropha curcas L were investigated in Burkina Faso. Prospecting and collection were carried out the plantations and hedges of J. curcas distributed in different climatic zones of Burkina Faso. The results indicate that foliar diseases are present in all climatic zones of the country. Mainly 4 foliar pathologies were recorded in the 18 sites of the study. These are yellowing of leaves with brown spots, yellowing of leaves with brown spots and black mycelium, drying of leaves from the border and virus diseases. The frequencies of observation of the various diseases show that the yellowing of the leaves with brown spots is the most disease predominant manifestation with a frequency of observation of 72%. Yellowing of the leaves with a presence of black spots and mycelium occupies the second rank with a prevalence of 33% followed by drying of leaves from borders and viroses with frequencies of 22 and 11% respectively. ANOVA analysis has shown that the climatic zone has a significant effect on the distribution of leaf viruses and leaf burns and a non-significant effect on yellowing of the leaves with or without brown spots and mycelium. The characterisation of fungal pathogens associated with these diseases identified Fusarium oxysporum, Fusarium solani, Fusarium subglutinans, Phoma sorghina, Botrytis cinerea, Curvularia lunata, Botryodiplodiat hreobromae, Cercospora cesami and Curvularia eragrostidis. Curvularia lunata is the most widespread with a frequency of 44% followed by Fusarium solani with a frequency of 33%. The most seldom observed are Cercospora cesamiand Fusarium subglutinans with a frequency of 10%. Among these characterised species, pathogenicity tests identified Botryodiplodia threobromae, Curvularia lunata, Fusarium solani and Curvularia eragrostidisas the pathogenic species of observed leaf diseases of J. curcas. These results confirm that Jatropha is infested by many fungal species. There is yet an urgency to develop a plant health program adapted to the local context to fight these fungal pathogens.