Biological Control of Trichoderma harzianum on Agaricus bisporus by Tea Tree Oil and Bacillus subtilis

摘要

Green mould caused by Trichoderma harzianum have been detected in Agaricus farms in Serbia. The disease symptoms were rusty spots and necrotic lesions on mushroom pilei and stipes. Progressive symptoms were white-colored mould, rapidly invading the casing after few days, becoming pale green and intensive green due to sporulation of the pathogen. The aims of the study were to evaluate biological efficacy and effectivness of the organic biofungicides tea tree oil and Bacillius subtilis in comparison with that of the commercial fungicide prochloraz-manganse against T. harzianum. Plastic bags, filled with 18 kg of compost spawned with A. bisporus strain Sylvan A15, were used. Plots were inoculated with a total volume of 10 mL of conidial suspension of T. harzianum at a rate of 1 000 conidia/m2. After artificial inoculation of T. harzianum in experimental growing room, rusty spotted diseased fruiting bodies of A. Bisporus were obsereved on the 16th day. Small white colonies appeared on the casing surface on the 29th day. Tea tree oil showed lower biological efficacy than in combination with fungicide. On the other hand, B. subtilis applied alone attained higher biological efficacy than together with prochlorazmanganese. Both B. subtilis and prochloraz-manganese applied alone have higher biological efficacy than combined together. Contrary, tea tree oil and fungicide applied together exhibited better biological efficacy than used alone. Prochlorazmanganese exhibited higher effectivness applied alone than used in combinations with biofungicides. Tea tree oil combined with fungicide had no negative influence on A. bisporus productivity although displeyd strong antagonism in disease control. Bacteria B. subtilis and prochloraz-manganese revealed less antagonism then previous, but had negative influence on mushroom yield.