CONTROL OF GROWTH AND SPORULATION FUNGI ASSOCIATED WITH ONION BULBROT USING FUNGICIDES

Onion is a crop that is consumed in almost every household in Nigeria for a wide variety of dishes. The crop has a fairly constant demand and uses not limited to any climate or associated with any nationality. Like any other crop, onion is subject to attack by a number of pathogens especially fungi. Onion bulbrot causes serious yield loss up to 10-50%. This has to be controlled for profitable production. Diseased onion bulbs from four different locations (Sokoto, Zaria, Kebbi and Kano) were obtained in order to isolate and identify the fungal pathogens that are associated with the onion bulbrot. Two pathogens (Fusarium oxysporium and Aspergillus niger) were isolated from all the samples collected from the four locations. Four different fungicides (Benlate, Rovrin, Delsene M and Rovral TS) were assessed in vitro to determine the most effective among them in controlling the mycelial growth of the two pathogens isolated. Delsene M completely inhibited the mycelial growth of the two pathogens at half the recommended rate. This was followed by benlate which also gave complete control of the mycelial growth at half the recommended rate of the two pathogens. Rovrin however gave complete inhibition of the growth of the two pathogens at the recommended rate, but had the least control in the three concentrations tested.