Determination of <i>Fusarium</i> Species Associated with Onion Plants (<i>Allium cepa</i>) in Field in Burkina Faso Causing Damping-Off and Bulb Rots
Konwendé Raïssa Kintega, P. Elisabeth Zida, Romain W. Soalla, Vianney Tarpaga, Philippe Sankara, Paco Sereme
Abstract
Onion (Allium cepa L.) is the second most important vegetable crop in Burkina Faso and provides an important source of income for those involved in the sector. However, producers are facing significant pre-harvest and post-harvest losses. To date, knowledge of major diseases of the crop is limited, limiting the development of effective control strategies. The objective of this study was to test the pathogenicity of some species of Fusarium. To this end, 33 fungal isolates collected from onion plants in 17 localities and belonging to five Fusarium species were used to inoculate onion seeds and bulbs to determine the pathogenic species responsible for damping-off on seedlings and basal bulb rot in Burkina Faso. The virulence of pathogenic isolates was determined according to the percentages of seedling damping-off evaluated 28 Days After Sowing, and the extent of rot in millimetres on inoculated bulbs. The evaluation of isolates on seedlings revealed that the most pathogenic isolates belong to the species F. proliferatum (I29, I21, I37, I33, I31), F. thapsinum (I35) and F. solani (I38) which resulted in 58.33% - 70.83% of seedling damping-off. The most pathogenic isolates on bulbs belong to the species F. proliferatum (I4, I29, I32) and F. oxysporum (I52, I50, I16) which caused 21.67 to 25 mm of rot on bulbs. Isolate I29 was very virulent on both seedlings and bulbs. The isolates of F. fujikuroi species were all low pathogenic on seedlings but one of them, (I27), expressed average pathogenicity on bulbs.