Eficiência do controle químico preventivo da ferrugem asiática (Phakopsora pachyrhizi) da soja em semeadura tardia na região sudoeste do Paraná

Abstract

Soybean is one of the main commodities on the world economy and we can consider the Asian rust as the main disease of culture, there are decreases in productivity of up to 70-90% already registered, which is caused by the phytopathogen (phakpsora pachyrhizi). The control of the disease is mostly done by the use of fungicides, they are asked about the sensitivity of the fungus to be controlled or develop some mechanism of resistance in relation to the products and the way they are applied. Crop monitoring makes a preventive control early in the infection, thus preventing the damage caused by the disease are exacerbated. In late sowings for high inoculum pressure and causes a lower sensitivity of the fungus to products for the control of the disease. The experiment in the experimental area Federal Technological University of Paraná - Campus Pato Branco. The applications of fungicides were carried out fromcthe first symptoms of Asian Rust. The experimental design was of randomized blocks where there were six treatments: witness, Ativum ® EC (pyraclostrobin + epoxiconazol + fluxapiroxade), Fox ® (trifloxystrobin + protioconazol), Ativum ® (pyraclostrobin + epoxiconazol + fluxapiroxade) + Unizeb Gold ® (mancozeb), Fox ® (trifloxystrobin + protioconazol) + Unizeb Gold ® (mancozeb) and Unizeb Gold ® (mancozeb) and four replicates. The severity was evaluated with the aid of diagrammatic scale and evaluated from the data using analysis of variance, and Scott-Knott test at 5% level of significance. Preventive applications through a monitoring are efficient for achieving productivity in the use of multisite products, not taking into account the cost of the applications by the fact that there are a large number of applications.