Efficacy of Bioagents and Fungicides Against Pyricularia setariae Causing Blast of Foxtail Millet Under In Vitro and Field Conditions

Foxtail millet (Setaria italica) is a climate-resilient minor cereal valued for its nutritional profile and adaptability to rainfed systems, yet its productivity is severely hindered by blast disease caused by Pyricularia setariae and P. grisea. This study evaluated the efficacy of selected fungicides and bioagents against Pyricularia spp. through in vitro and field trials at Mahatma Phule Krishi Vidyapeeth during the Kharif 2024–2025 season. In vitro assays revealed that Trichoderma harzianum achieved complete mycelial inhibition (100%), while Pseudomonas fluorescens showed moderate inhibition (63.51%). Among fungicides, Tebuconazole 50% + Trifloxystrobin 25% WG, Tricyclazole 75% WP, and Carbendazim 12% + Mancozeb 63% WP exhibited total inhibition of fungal growth. Field evaluations demonstrated that Tebuconazole 50% + Trifloxystrobin 25% WG significantly reduced disease intensity (PDI ~15%) and achieved the highest disease control (65.59%), followed by Carbendazim 12% + Mancozeb 63% WP and Tricyclazole 75% WP. Bioagents provided moderate disease suppression but were less effective than chemical treatments under field conditions. Notably, Pseudomonas fluorescens significantly enhanced grain yield (11.75 q/ha), indicating its dual role in disease suppression and plant growth promotion. The results underscore Tebuconazole 50% + Trifloxystrobin 25% WG as the most potent fungicidal treatment and highlight the promise of T. harzianum and P. fluorescens for integration into eco-friendly and sustainable blast management strategies in Foxtail millet. Together, these findings advocate for an integrated disease management approach combining chemical and biological agents to mitigate blast incidence and enhance Foxtail millet productivity.

⓿ Tebuconazole + Trifloxystrobin achieved the greatest blast suppression in Foxtail millet, delivering the lowest disease intensity and highest yield improvement under field conditions, outperforming all other fungicidal treatments.

⓿ Trichoderma harzianum completely inhibited Pyricularia setariae in vitro, demonstrating strong antagonism, while Pseudomonas fluorescens provided moderate inhibition and contributed to yield enhancement through growth-promoting effects.

⓿ Integrated evaluation revealed that fungicides ensured superior field protection, whereas bioagents offered sustainable complementary activity, supporting their combined use in environmentally compatible Foxtail millet blast management strategies.