Application of organic waste material overgrown with Trichoderma atroviride as a control strategy for Sclerotinia sclerotiorum and Chalara thielavioides in soil

The effect of granulated organic waste material overgrown with Trichoderma atroviride TRS25 on the survival of Sclerotinia sclerotiorum and Chalara thielavioides in the soil was investigated. Application of this material into the soil at a dosage of 1% (w/v) reduced the survival of S. sclerotiorum sclerotia to almost zero after 2 months of incubation. The sclerotia were parasitized by T. atroviride fungus multiplied on granulates. The detrimental effect of granulates on Ch. thielavioides was observed after 4 months of incubation. The granulates, with Trichoderma and without the fungus, caused a decrease of the pathogen population in soil. Trichoderma atroviride introduced into the soil as a conidia suspension did not decrease the amount of Ch. thielavioides but the fungus parasitized S. sclerotiorum sclerotia. After the addition of granulated waste material, an increase of bacteria, especially the Pseudomonas group in the soil was observed.