Inhibition and control effects of the ethyl acetate extract of Trichoderma harzianum fermented broth against Botrytis cinerea

Botrytis cinerea is a widespread parasitic fungus that infects many crops and reduces their productivity. Trichoderma harzianum, also a fungus, has been commercially used as a biofungicide to control B. cinerea. The spores of T. harzianum, currently used in the application, have some drawbacks such as efficacy affected by the environmental condition and sensitivity to chemical fungicides. Instead of using the living microbe, the extract from T. harzianum fermented broth may be applied to control B. cinerea. It was found that the extract could inhibit mycelial growth (EC50 = 13.6 mg/L), conidia germination (EC50 = 17.5 mg/L) and conidia production (EC50 = 23.6 mg/L) of B. cinerea. In vitro, the extract showed excellent control effects on tomato grey mould caused by B. cinerea and the protective effect (EC50 = 99.6 mg/L) was better than the therapeutic effect (EC50 = 135.8 mg/L). In pot experiments, the extract also showed persistent protective (EC50= 99.0 mg/L at day 7 and EC50 = 142.7 mg/L at day 15) and therapeutic (EC50 = 195.0 mg/L at day 7 and EC50 = 393.7 mg/L at day 15) effects over 15 days. This study showed that the extract was equivalent or superior to the commercial dicarboximide fungicide, procymidone. In conclusion, the ethyl acetate extract of T. harzianum fermented broth is effective in the treatment of tomato grey mould caused by B. cinerea.   Key words: Botrytis cinerea, fungicide, tomato grey mould, trichodermin,Trichoderma harzianum.