Sclerotium rolfsii Sacc. is a destructive soil-borne pathogen causing collar rot in chili (Capsicum spp.) and several other diseases in many economically important crops. This study evaluated the efficacy of nine fungicides representing different chemical classes (triazoles, strobilurins, benzimidazoles, dithiocarbamates, and contact fungicides) against S. rolfsii using the poisoned food technique under in vitro conditions at 25, 50, and 100 parts per million (ppm) concentrations. Most systemic fungicides significantly inhibited mycelial growth compared to the untreated control, whereas captan, copper oxychloride, and mancozeb showed poor inhibition at lower concentrations. The highest inhibition of mycelial growth over control was observed with carboxin + thiram (91.25%) at 50 ppm and maintained approximately 90% inhibition across all tested concentrations. Triazole-based fungicides, including propiconazole and hexaconazole, as well as the triazole-strobilurin combination fungicide, tebuconazole + trifloxystrobin, also showed substantial inhibition (41–74%) compared to control. In addition, complete suppression of sclerotia formation was observed with carboxin + thiram, hexaconazole, propiconazole, and tebuconazole + trifloxystrobin at all tested concentrations. These findings suggest that carboxin + thiram and selected triazole- and strobilurin-based fungicides could be effectively integrated into collar rot management programs in chili for improved disease management.
Gurung et al. (Wed,) studied this question.