Abstract
The known amounts of the active ingredients of Dithane, Phygon, Spergon, SR-406 and Arasan solved in solvents put into petri dishes respectively, and then exposed under dried and moist conditions in a greenhouse (average temp. 24°C-25°C.) for 1 to 7 days.
The petri-dish germination was used for the determination of the ED 95 values for each ingredients with rice blast fungus, Piricularia oryzae.
The decrease of fungitoxicity was observed in all chemicals under both conditions, but it was more remarkable under moist than dried condition. Among the tested chemicals, Phygon, Spergon and Arasan were relatively tolerant to the effect of weathering.
