Evaluation of fungal antagonists for control of onion white rot in soil box trials

Four fungi ( Chaetomium globosum, Trichoderma viride, T. harzianum, Trichoderma sp.) were capable of reducing the incidence of onion white rot relative to the untreated control in two soil-box trials. When applied as a soil additive (sand: bran: fungal homogenate, 1:1:2) at the rate of 0-1% wheat bran/g dry soil, all fungal isolates provided levels of disease control equivalent to the fungicide (procymidone 0-5 g a.i./100g seed) treatment. The best results were achieved with the Chaetomium globosum and Trichoderma (C62) isolates which gave 78% and 73% control of white rot. respectively, in trial 1 and 67% and 73% control, respectively, in trial 2. Reduced control was observed when the test fungi were applied as seed coatings or incorporated into alginate pellets.