Efficacy of Fungicides against Myrothecium roridum, the Causal Agent of Leaf Spot in Sesame (Sesamum indicum L.) under In vitro and In vivo Conditions

ABSTRACT Sesame (Sesamum indicum L.), a vital oilseed crop in India and worldwide, is frequently constrained by foliar diseases, particularly leaf spot caused by Myrothecium roridum. The pathogen causes severe yield losses and deteriorates oil quality, making its management critical for sustaining sesame production. The present study evaluated the efficacy of systemic and non-systemic fungicides through in vitro assays, seed treatment trials, and field experiments. Eighteen fungicides were screened against M. roridum using poisoned food technique, followed by seed treatment trials on naturally infected sesame seeds, and replicated field trials under Kharif conditions. In vitro results indicated complete inhibition (100%) of fungal growth by Benomyl, Bavistin, Metalaxyl, Vitavax, Topsin-M, and Thiram. In seed treatment studies, Vitavax and Bavistin recorded the highest reduction in seed-borne infection (94.0% and 90.2%, respectively). Field experiments over two years revealed Bavistin (0.10%) and Benomyl (0.15%) as the most effective foliar sprays, reducing disease incidence by 75–78%, followed by Metalaxyl (72%). The findings suggest that fungicides, especially Bavistin and Benomyl, can play a central role in integrated disease management modules for sesame. Keywords: Sesame, Myrothecium roridum, leaf spot, fungicides, seed treatment, field evaluation.