Assessment of Effective Chemical Fungicide for Managing Spot Blotch Disease in Wheat

<p><span>A field experiment was conducted from November 2022 to March 2023 at the University Research Farm, Uttar Banga Krishi Viswavidyalaya, Pundibari, West Bengal, to evaluate the efficacy of eight chemical fungicides for managing spot blotch disease in wheat caused by <em>Bipolaris sorokiniana</em>. The experiment included systemic and contact fungicides <em>viz.,</em> Propiconazole, Tebuconazole, Mancozeb, Carbendazim, and their combinations. The wheat variety RAJ 4015, highly susceptible to spot blotch, was used under a randomized block design. The pathogen was isolated, purified, and mass-multiplied for artificial inoculation. Fungicides were applied twice at heading and anthesis stages. Disease progress was monitored, and data on disease severity, AUDPC (Area Under Disease Progress Curve), percent disease reduction index (PDRI), percent increase in yield (PIY), and benefit-cost (B: C) ratio were recorded. All the fungicide treatments significantly reduced disease severity compared to the untreated control. The combination of Propiconazole 13.9% + Difenoconazole 13.9% proved most effective, resulting in the lowest AUDPC (476), highest PDRI (49.82%), and PIY (52%). However, sole Propiconazole 25% EC recorded the highest B: C ratio (1.37), suggesting greater economic viability despite slightly lower disease suppression. The findings indicated that while Propiconazole + Difenoconazole offered superior disease control and yield enhancement, Propiconazole 25% EC emerged as the most cost-effective option for integrated spot blotch management in wheat.</span></p>