Management of Powdery Mildew of Blackgram through Novel Fungicides and Bioagents

Aim: Powdery mildew, caused by obligate biotrophic fungi of the order Erysiphales, is a major yield-limiting disease in blackgram, leading to losses of 20–30%. While cultural and biological methods offer partial control, they are often insufficient and reliance on conventional fungicides poses risks of resistance development. This study aims to evaluate the efficacy of novel fungicides and bioagents against powdery mildew in blackgram, in comparison with a standard recommended fungicide and to identify effective and sustainable management strategies. Methodology: Field experiments were conducted during two consecutive years of rabi 2023–2024 and 2024–2025 to evaluate the efficacy of novel fungicides and biocontrol agents in managing powdery mildew disease of blackgram at RARS, Lam, Guntur, India. Results: The pooled analysis of both the years resulted that, among the tested treatments, the novel fungicide, Cyflufenamid @1.0 ml l-1 exhibited the highest reduction in disease severity (70.81%) followed by Hexaconazole @ 2.0 ml l-1 (chemical check) with 40.77% when compared to the untreated control. Whereas, the biocontrol agents Ampelomyces quisqualis @ 5.0 ml l-1 and Bacillus subtilis @ 5.0 ml l-1 were statistically on par, reducing disease severity by 31.89% over the control. The lower AUDPC values were recorded in the chemical and bioagent treated plots when compared with the untreated control. Yield enhancement was significantly higher in Cyflufenamid-treated plots, recording a 60.19% increase over the control with a maximum cost-benefit ratio of 2.36. Conclusion: The study highlights the growing need for novel fungicides due to rising resistance in powdery mildew pathogens and combining novel fungicides and bioagents as an integrated approach for ensuring sustainable disease management.