Identification of Fusarium Species Associated with Onion (Allium cepa L.) Plants in Field in Burkina Faso

Many fungi limit onion production in Burkina Faso. This study aims to identify the main Fusarium species associated with onion plant in field in order to determine those involved in seedling damping-off and bulb rot, and develop adequate management strategies of these diseases. For this purpose, 36 isolates of Fusarium were isolated from onion plants in 17 sites and subjected to molecular analysis and biometric characterization. The results revealed that the isolates belong to five Fusarium species: Fusarium oxysporum (44.44% of the isolates), Fusarium proliferatum (41.66%), Fusarium solani (5.55%), Fusarium fujikuroi (5.55%) and Fusarium thapsinum (2.77%). Fusarium oxysporum, F. proliferatum, F. solani and F. fujikuroi had faster mycelial development, with a growth rate of 7.72 - 8.27 mm/d, than F. thapsinum (6.52 mm/d). Conidia of F. oxysporum, F. proliferatum and F. solani were longer (4.74 - 5.96 μm) than those of F. fujikuroi and F. thapsinum (3.20 - 4.04 μm). Fusarium solani and F. oxysporum, respectively, had the largest and most partitioned conidia.