Use of Copper-Based Pesticides to Control Fungal Diseases of Soybean in Northern Brazil

Abstract

At level word fungal diseases that affect soybean crop are one of the main causes of low productivity and annual losses may reach 21% of total production. In this context, the objective of the study was to evaluate the efficiency of copper-based protectors associated with fungicides to control soybean diseases such as: asian soybean rust (Phakopsora pachyrhizi), target spot of soybean (Corynespora cassiicola) and cercospora leaf blight (Cercospora kikuchii) + frogeye leaf spot (Cercospora sojina) + brown spot (Septoria glycines), which together were considered as late-crop cycle diseases, with impact on grain yield, in the region of Aparecida do Rio Negro – TO, Brazil. Treatments were composed of different rates of copper-based pesticides associated with fungicides like Azimut® (first application), Orkestra® (second application), Ativum® (third application) and Horos® (fourth application) in soybean. Diseases were identified and crop damage evaluations on leaves were performed using LI-COR® portable meter 7 days after the fourth application. At physiological maturity, grain yield was evaluated. Combined rates of fungicides + Unizeb Gold® (1.5 kg ha-1), Difere® (0.5 L ha-1), and NHT® Copper Super at a rate higher than 0.109 L ha-1, were effective to control late crop-cycle diseases in soybean. Associated applications of fungicides + 0.219 L/ha of NHT® Copper Super reduced the severity of Asian soybean rust, target spot of soybean and late crop-cycle diseases with a greater increase in grain yield (4.5 Mg ha-1).