Selected fungicides and biocontrol agents for managing early blight of tomato caused by Alternaria solani

Abstract

The present research work was carried out for controlling early blight of tomato using selected fungicides i.e. Azoxystrobin 23% SC, Propiconazole 25% EC, Mancozeb 75% WP, Mancozeb 75%WP + Metalaxyl 35% WS and Copper oxychloride 50% WP, at three different concentrations (50, 75, 100 ppm) adopting poison food technique, and bio control agents (Trichoderma harzianum, T. koningii and T. virens) adopting dual culture technique. At the highest concentration of fungicide, the least average mycelial growth of Alternaria
solani was shown by Azoxystrobin 23% SC + APSA 80 (1%) (3.93 mm) followed by Propiconazole 25 % EC+ APSA 80 (1%) (7.93 mm), Mancozeb 75% WP + APSA 80 (1%) (19.94 mm), (Mancozeb 75% WP + Metalaxyl 35%WS) +APSA 80 (1%) (37.95 mm) and Copper oxychloride 50% WP+ APSA 80 (1%) (51.96 mm). Meanwhile at the same concentration i.e.,100 ppm added with APSA 80 @1%, Azoxystrobin 23% SC showed maximum inhibition of mycelial growth (95.63%), followed by Propiconazole25% EC (91.19%), Mancozeb 75% WP (77.84%), Mancozeb 75 %WP+ Metalaxyl 35% WS (57.83%). Least inhibition of
pathogen was observed in Copper oxychloride 50% WP (42.27%). Among bio control agents, the minimum colony growth of Aternaria solani was observed in Trichoderma harzianum (38.80 mm) followed by T. koningii (42.20 mm) and T. virens (45.80 mm). The highest inhibitory effect was observed after 7 days
with maximum inhibition in mycelial growth of (56.89%) shown by T. harzianum followed by T. koningii (53.11%) and T. virens showed less inhibition (49.11%).