Fungicidas no controle de doenças foliares e produtividade do milho

Abstract

Corn is an important crop, used for a variety of purposes — including animal feed, grain for human consumption, ethanol, as well as for high fructose corn syrup, sweeteners, starch, and for beverage/plastic/alcohol production. Diseases are among the major limiting factors for corn production. The aim of the research was to evaluate the efficiency of comercial fungicides on foliar diseases and corn yield. Experiment was conducted in Dourados, Brazil, in the 2019 corp season with Formula Viptera hybrid in a randomized complete block with four replications and eight treatments. The following fungicides were studied: Approve® (thiophanate-methyl + fluazinam), Aproach Prima® (picoxystrobin + cyproconazole), Ativum® (fluxapyroxad + pyraclostrobin + epoxiconazole), Fusão® (metominostrobin + tebuconazole), Nativo® (trifloxystrobin + tebuconazole), Orkestra® (fluxapyroxad + pyraclostrobin) e Priori Xtra® (azoxystrobin + cyproconazole). Fungicides were applied in the V8 and pre-tasseling stages. Two weeks after fungicide spray weekly evaluations of gray leaf spot (GLS) severity were initiated. Fungicide, regardless of product, were efficient for GLS control, Ativum®, Aproach Prima® and Nativo® resulted en 92%, 87% e 87% disease control, respectively. Ear diameter in plants sprayed with Ativum® e Fusão® were greater than the other treatments. Fungicides did not affect grain number per line nor line number per ear. Ativum® resulted in greater incidence of ears with poor kernel set. The number of ears per plot were affected by fungicides, Orkestra® e Priori Xtra® had greater number of ears per plot than Approve®. One-hundred grain mass was increased by Ativum® compared to control and Priori Xtra®. Aproach Prima® increased corn yield in 20% to the control but did not differ from the other fungicides studied.