Effect of Trichoderma isolates on Sclerotium rolfsii Sacc.

Sclerotium rolfsii Sacc. is one of the most important plant pathogens commonly causing root rot, stem rot, wilt and foot rot in various crop species. A wide range of host, profuse mycelial growth, and ability to produce persistent sclerotia makes them difficult to control. Biological control using Trichoderma could provide a sustainable tool for the management of diseases caused by S. rolfsii. One hundred four Trichoderma isolates were evaluated against S. rolfsii in vitro by dual culture. Of them, 30 Trichoderma isolates found effective were selected to study parasitization of sclerotia of S. rolfsii in vitro. Similarly, four Trichoderma isolates found effective in vitro were used to study their ability to parasitize sclerotia of the pathogen in soil. Trichoderma isolates varied significantly (p<0.001) for both the inhibition percentage and biocontrol index. However, they showed a differential effect as Trichoderma isolate T73, Forest soil had highest inhibition (96.96%), while Trichoderma isolate T49, Bhaktapur showed the highest bio-control index (99) against S. rolfsii. Trichoderma isolates T49, Bhaktapur and T87, Forest soil showed promising results in controlling S. rolfsii in vitro. Both isolates were also able to parasitize and reduce the germination of sclerotia in the soil. The present study demonstrated that selected Trichoderma had potential in controlling Sclerotium rolfsii.