Analysis of combined strategies for the management of Asian soybean rust

Abstract

Asian soybean rust, if not well managed, can reduce grain yield up to 90%. Due to the severe damage caused by the disease, especially in Brazil, it is important to evaluate management strategies combined with fungicides, to minimize the losses. The aim of the work was to evaluate the effect of adopting different combined management strategies on the severity of soybean rust and its impact on the performance of the crop. Research was carried out at 2016/2017 and 2017/2018 growing seasons. Soybean cultivar NA 5909 RG® (susceptible to Asian rust), LG 60163 IPRO® (highly tolerant) and TMG 7062 IPRO® INOX® (resistant) were evaluated with different combinations of fungicide, copper and potassium phosphites foliar fertilizers applications, in two development stages, R1 (early flowering) and R5.1 (early grain filling). Disease severity assessments were performed at R1 and repeated every 14 days (up to R5 + 14 days) to determine the area under the Disease Progress Curve (AUDPC). The genetics of resistance to Asian soybean rust contributed to the less progress of the disease in plants. Even with differential responses between cultivars and treatments applied to the severity of Asian soybean rust, the disease did not compromise grain yield in both growing seasons.   Key words: Phakopsora pachyrhizi, fungicide, foliar fertilizers, genetic resistance.