Field evaluation of some fungicides for controlling false smut of rice

Rice false smut disease caused by Ustilaginoidea virens (Cooke) Takahashi was known as one of the diseases of rice in some paddy fields of Guilan province in recent years. The present study was conducted to chemical control evaluation of rice false smut by application of tricyclazole (WP 75%), carbendazim+iprodion (Rovral-T-S® WP 52.5%), copper oxychloride (WP 35%), propiconazole (Tilt® EC 25%), and azoxystrobin+cyproconazol (Amistar Xtra® SC 28%) fungicides with dose rates of 0.5, 1, 3kg, 1 and 0.6 liter per hectare, respectively on a rice susceptible cultivar, namely Khazar at the mid boot and beginning of panicle emergence stages, in a field having multi-year infection in Abkenar location near the Anzali lagoon for two years. Data analysis showed that propiconazole, copper oxychloride and azoxystrobin+cyproconazol fungicides had significant effects on reducing of infected tillers (panicles) and pathogen sporeballs number per square meter and disease severity in first year (2011). Whereas the effects of tricyclazole and carbendazim+iprodion were not significantly differ from control treatment. In second year (2012) the disease severity was seriously developed in the field, but the application of propiconazole was more effective than other fungicides to reduce number of infected tillers (panicles) and pathogen sporeballs per square meter and disease severity in comparison with control treatment by percentage rates of 80.62, 83.92 and 83.01 respectively. So application of propiconazole at booting stage can be introduce to reduce disease incidence of false smut in paddy fields of northern Iran.