Mitigation of rice blast (Pyricularia grisea) by integrating chemical and biological management strategies

Regarded as one of the most significant fungal infections affecting rice is rice blast. Though resistant cultivars used to manage with the disease with vertical resistance but the pathogen Pyricularia oryzae has quickly been able to overcome single gene resistance resulted in susceptible reactions. Since a long time, chemical control remains the most effective disease management strategy for minimizing the yield losses. Integrated applications of chemical with biocontrol agents have been exercised from last few decades showed to be a heterogeneous approach. In the current study, a field experiment was conducted for two consecutive years of 2022 and 2023 using chemicals, biological control agents and their combinations. All the fungicides and biocontrol agents successfully reduced the severity of leaf blast as well as the neck blast and increased crop yield. Tricyclazole + hexaconazole proved most effective against leaf and neck blast and recorded with least disease severity of 8.15 and 10.23 percent respectively. Integrated application of Trichoderma harzianum and propiconazole also found effective with recorded severity of 11.83 and 14.79 percent respectively. Results showed the synergistic effects of 'fungicide-fungicide' or 'fungicide-biocontrol agent' proved to be best to manage blast disease of rice.