Rice blast control with a throw-in packed formulation containing pyroquilon

The properties of throw-in packed fungicide, packed fine granules containing pyroquilon 24% per pack in a water-soluble film (Coratop®-Pack, 50g/each pack), were investigated as a rice blast control agent. Analytical results on pyroquilon concentrations in surface water and soil after application of the formulation in paddy fields clarified that the diffusion of pyroquilon was fast and uniform within a field. The control efficacy of the formulation was remarkable against the blast at 120 to 156g a. i. of pyroquilon/10a. At the same dose rate, pyroquilon concentration in the leaves of rice plants peaked after 3 days, and was found to remain more than 0.1ppm up to 4 weeks after the application. Control of leaf blast was achieved by application of the formulation at 10 to 20 days before infection with long lasting efficacy for more than 40 days, which might contribute to the panicle blast control. Control of panicle blast was achieved by application of the formulation at 13 to 34 days before heading. These results show that the throw-in packed formulation of pyroquilon is not only useful for labor-saving application but also as effective to rice blast control as its granule formulation.