Journal of Experimental Agriculture International

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).