IN VITRO ASSESSMENT OF FUNGICIDES FOR THE CONTROL OF SORGHUM ANTHRACNOSE INDUCED BY COLLETOTRICHUM GRAMINICOLA (CESATI) WILSON

Foliar spraying of fungicides is not widely practiced in sorghum production for a number of reasons, namely, high cost of chemicals, most cumbersome and not economically profitable, therefore, there is need to evaluate the efficacies of some selected fungicides in the laboratory with a view to recommending them as seed dressers for the control of anthracnose on the crop. In view of this, three fungicides, benomyl at 1.5g a.i./l, metalaxyl at 1.0g a.i./l and mancozeb at 6.25g a.i./l were evaluated under labopratory conditions to assess their effects on the mycelia growth of Colletotrichum graminicola, arranged in a completely randomized design. The three fungicides inhibited mycelia growth of Colletotrichum graminicola. Conpared to the control check (sterile distilled water) which covered the plate (6.7cm), benomyl, metalaxyl and mancozeb caused a reduction in the mycelia growth to 34.3%, 20.9% and 58.2%, respectively. The colony diameter of the fungus was significantly reduced to 2.3cm, 1.4cm and 3.9cm , respectively (p=0.05) by these fungicides at lower concentrations of benomyl (0.19g a.i./l), metalaxyl (0.13g a.i./l) and mancozeb (0.78g a.i./l). Thus, metalaxyl gave the most effective control of the fungus at P=0.05.