EFFICIENCY LOSS OF RECORDED FUNGICIDES FOR THE CONTROL OF ASIAN SOYBEAN RUST IN CENTRAL REGION OF BRAZIL

Abstract

Due to grower allege of low efficiency of triazole fungicides in recent years in Central Brazil on the control of Asian soybean rust (Phakopsora pachyrhizi), this study was undertaken to demonstrate the efficiency loss of products registered for rust and applied alone and to evaluate the efficiency of fungicides mixtures. The trials were carried out in five locations in Brazil, in the 2009/10 growing season. The experimental design was completely randomized blocks with four replications. Ten mixtures of triazole + strobilurin and two applications of pure triazoles were evaluated and the control without application. The application of fungicides started in the R1/R2 stage or in any vegetative stage if infections occurred early. The mixtures of fungicides were effective in controlling Asian soybean rust. Application of sole triazole fungicides was less effective in controlling the rust than the mixtures of triazoles + strobilurins. The use of commercial mixtures of triazole with strobilurin for rust control is recommended.