Controle da ferrugem asiática da sola e suas relações com a planta, manejo e tecnologia de aplicação

Abstract

Asian soybean rust is a disease that more reduce crop productivity in Brazil. There is a positive correlation between healthy leaf area and grain yield damage. The control is based on the fungicidal application whose efficiency is dependent on proper technology application. The greatest difficulty in fungicidal application are the leaves located in the middle and lower crop canopy, where traditional spraying technologies fail to achieve the targets. The use of correct fungicides application can result in a better ASR control. The objective of this thesis was to address issues related to fungicide application technology to improve control. The field and laboratory experiments were carried out in 2013/2014, 2014/2015 and 2015/2016 growing seasons. In the first experiment the dry matter accumulation in grains and soybean yield components depending on healthy leaf area duration were quantified. In a second set of experiments applying auxiliary systems (Dropleg® and Vortex®), plant row spacing, and cultivars were evaluated. In the third group the effect of adjuvants added to fungicides on Asian soybean rust control performance, coverage and fungicidal suspension deposits were evaluated. The results showed that: a) variations in soybean leaf area and healthy leaf area duration infected by disease, showed effect on dry matter accumulation, yield components, grain yield and, seeds quality; b) the systems of tested fungicide application were not more efficient than the conventional system on covering and deposit in the lower crop canopy and on ASR control; c) there were yield increases with row spacing smaller than 0,51m, and genetic cultivar resistance decreased rust damage; d) Adjuvants showed improvement on biological effectiveness in the field, fungicide suspension pH, electrical conductivity, and target deposit and coverage.