Journal of Basic and Applied Research International

Groundnut (Arachis hypogaea L.) is an important oilseed crop, but its productivity is affected by stem rot caused by Sclerotium rolfsii Sacc. Biological control using antagonistic fungi offers a potential approach for reducing dependence on chemical disease management. The present study evaluated the in vitro inhibitory activity of cell-free culture filtrates from ten native isolates of Trichoderma viride against S. rolfsii. The pathogen was isolated from infected groundnut stem tissues and identified based on colony morphology and sclerotial characteristics. T. viride isolates were obtained from rhizosphere soil samples and maintained as Tv₁ to Tv₁₀. Culture filtrates were prepared from 10-day-old potato dextrose broth cultures and incorporated into potato dextrose agar at 10%, 20%, 30% and 40% concentrations using the poisoned food technique. All isolates reduced radial mycelial growth of S. rolfsii compared with the control and inhibition generally increased with filtrate concentration. Among the isolates tested, Tv₄ showed the greatest inhibitory effect, restricting pathogen growth to 27.79 mm, 19.56 mm, 12.26 mm and 0.00 mm at 10%, 20%, 30% and 40% concentrations, respectively. Complete inhibition was observed with Tv₄ at a 40% concentration. Tv₆, Tv₇ and Tv₈ also showed high inhibition at the highest concentration. These results indicate that T. viride culture filtrates can suppress S. rolfsii growth under in vitro conditions.