Vol. 9, Special Issue 12, Part H (2025)

Onion (Allium cepa L.) indeed holds significant importance globally, not just as a culinary staple but also for its numerous health benefits. Amongst all important diseases, purple blotch disease incited by Alternaria porri is the major hurdle in successful and profitable cultivation of onion. In recent years, purple blotch disease is an important emerging disease of onion in Konkan region as well as rest of the Maharashtra causing considerable yield losses. The effectiveness of phytoextracts, bioagents and fungicides against Alternaria porri were assessed in vitro using the standard "Dual culture technique." All the bio-agents evaluated were significantly effective in inhibiting the mycelial growth of A. porri. Pseudomonas fluorescens was shown to have the greatest (78.88%) mycelial growth inhibition of A. porri. Soapnut rind extract (10%) outperformed all treatments, with the highest suppression of mycelial growth (75.73%) of A. porri. Among the systemic fungicides, Tebuconazole 25.9% EC, Hexaconazole 5% EC and Propiconazole 25% EC each @ 0.1% concentration were found most significantly effective and caused complete inhibition of A. porri. Among the contact and combi fungicides, Tebuconazole 50% + Trifloxystrobin 25% WG (0.05%) and Copper oxychloride 50% WP (0.25%) were found most significantly effective in inhibiting the mycelial growth of Alternaria porri with complete inhibition over control.