In vitro exploration of bioagents and fungicides against stem rot of white onion (Allium cepa L.) caused by Sclerotium rolfsii Sacc.

Abstract

Stem rot caused by Sclerotium rolfsii Sacc. is a destructive disease that significantly affects white onion production in the Konkan region of Maharashtra. This study examined the efficacy of various bioagents, including Trichoderma harzianum, T. longibrachiatum, T. koningii, Pseudomonas fluorescens, Bacillus subtilis and Aspergillus niger and fungicides viz., captan 50% WP, azoxystrobin 23% SC, tebuconazole 25% EC, propiconazole 25% EC, hexaconazole 5% EC, carbendazim 12% + mancozeb 63% WP, tebuconazole 50% + trifloxystrobin 25% WG, thiophanate methyl 70% WP, carbendazim 50% WP, and copper oxychloride 50% WP for their in vitro efficacy against S. rolfsii. Among the bioagents, T. koningii showed the highest percent inhibition of 62.03% followed by T. harzianum (58.14%). In terms of fungicides azoxystrobin 23% SC, tebuconazole 25% EC, propiconazole 25% EC, hexaconazole 5% EC (each at 0.1% and 0.2%), and tebuconazole 50% + trifloxystrobin 25% WG (at 0.05% and 0.1%) were most effective, completely inhibiting the test fungus at both lower and higher concentrations.