Management of rice blast with modern combination fungicides against Magnaporthe oryzae

Blast of Rice ( Oryza Sativa L.) caused by Magnaporthe oryzae is a devastating disease that restrain significant yield under field conditions. The efficacy of modern combination fungicides against blast disease of rice was evaluated under in vitro and in UBN (Uniform Blast Nursery) from Telangana at ICAR-IIRR (Indian Institute of Rice Research), Rajendranagar, Hyderabad during Rabi-2022, on the var. HR-12. All fungicides exhibited the considerable levels of inhibition during the study, however, Tricyclazole 70% WP @ 600 ppm was found to be the best concentration with complete inhibition after 14 DAI (Days after inoculation) compared with control. Triazole chemical group in combination with strobilurin group molecules such as Hexaconazole 5% EC, Difenconazole 25% EC, Tebuconazole 250 EC and Azoxystrobin 11% + Tebuconazole 18.3% (w/w) SC) were effective at 500 ppm. Various strobilurin group of molecules in combination with Triazole molecules (Azoxystrobin 18.2% + Difenconazole 11.4% SC; Metiram 55% + Pyraclostrobin (5%) WG; Tebuconazole 50% + Trifloxystrobin 25% w/w (75 WG) were tested for their efficacy under UBN conditions at a constant dosage of 1.0 ml/1 and effectively reduced the blast disease PDI to 26.66%, 20.63% and 14.6%, respectively compared to control PDI of 54.46%. with AUDPC and r 324.8 units −1 and an average of 0.04 units −1 day when compared with control.