Efficacy of a mixture fungicide tricyclazole + thiophanate methyl in comparison with some commonly used fungicides in controlling of rice blast disease in northern Iran

Blast disease caused by Pyricularia oryzae is the principal disease of local rice cultivars innorthern Iran. Because of this, its chemical control is being in possession of special priority.Application of various fungicides and fungicides mixture is an important strategy on the chemical management of this disease. In this study efficacy of Vista®, as a fungicide mixture (tricyclazole + thiophanate methyl WP 72.5%) was evaluated in controlling of rice leaf, panicle, neck and node blast disease with dose rates of 400, 500 and 600 g/ha, in comparison with recommended fungicides, tricyclazole (WP 75%), carpropamid (SC300 50%) and edifenphos (EC 50%) with dose rates of 500g, 400 ml and 1000 ml per hectare respectively, in randomized complete block design under field condition in 2010 and 2011. In Rasht county, the results revealed that the effects of fungicides Vista® with all three dosages, carpropamid and tricycalazole were more significant to control of leaf blast on Hashemi cultivar in comparison with control treatment, at both time ofevaluation. All fungicides had significant effect to reduce panicle and node blast (exceptedifenphos) in first year and neck blast (except edifenphos) in second year. In second year node blast was seriously developed and application of tested fungicides was not significantly effective to reduce of node blast in comparison with control treatment. In Amol county, edifenphos was the least effective of all the fungicides in controlling of leaf blast disease as similarly found in Rasht county.