Isolation and in-vitro evaluation of bioagents and fungicides for the management of early leaf blight of tomato (Alternaria solani)

Abstract

Early blight of Tomato incited by Alternaria solani is considered to be the most devastating disease occurring all over the world. The present investigation on " Isolation and In-vitro Evaluation of Bioagents and Fungicides for the Management of Early Leaf Blight of Tomato (Alternaria solani)." was undertaken during 2024-2025 on the aspect viz., isolation, in vitro evaluation of bioagents, systemic, non-systemic and combi-product fungicides of fungicides and bioagents at Department of Plant Pathology, VNMKV, Parbhani. Typical early blight symptoms observed in the Department of Horticulture field at COA, Parbhani, included circular brown spots with concentric rings, which later coalesced, causing blighting, defoliation, stem cankers, and fruit rot under severe infection. The pathogen’s identity was confirmed as Alternaria solani (Ellis and Martin) Jones and Grout based on symptoms, cultural and morphological features, microscopic examination on the susceptible Tomato local variety. in vitro evaluation of fungicides and bioagents revealed that the systemic fungicide Difenoconazole, the non-systemic fungicide Mancozeb and the combi-fungicides Azoxystrobin + Tebuconazole and Azoxystrobin + Difenoconazole showed the highest inhibition of mycelial growth (100%), with the least colony diameter (6.66 mm). Among bioagents, Trichoderma harzianum was most effective, completely inhibiting the mycelial growth (0.00 mm, 100% inhibition), followed by T. asperellum (16.00 mm & 82.21%).