PEDRO VITOR SCHUMACHER
Abstract:
Two experiments were undertaken aiming to evaluate the effects of the pyraclostrobin fungicide applied at different times and combinations on two simple corn hybrids in the first and second harvests at the Cerrado. The first experiment was undertaken during the 2013/14 harvest adopting a randomized block design in a factorial 2 x 9 (hybrid x pyraclostrobin applications), having four replications. The applications were performed in different combinations: presence or absence of pyraclostrobin + thiophanate methyl + fipronil (100g a.i. 100kg seed-1) in seed treatment (V0) combined with pyraclostrobin (150g a.i. ha-1) application before or after topdressing (V4 or V6) combined or not with pyraclostrobin + cyproconazole (137.25g a.i. ha-1) application in pre-bolting (VT) and a control (on which pyraclostrobin wasn’t used). The second experiment was undertaken during the second harvest of the year 2014, adopting a randomized block design in a factorial 2 x 8 (hybrid x pyraclostrobin applications), having four replications. The applications were performed as doses of 0, 150, 300 and 600g i.a. ha-1 in V6, combined or not with the application of pyraclostrobin + cyproconazole as a dose of 137.25g i.a. ha-1 in pre-bolting (VT). An F test was performed over the collected data to analyze the significance and a Tukey test was performed to compare the means, both tests being run at a 5% probability. No effects of the application of pyraclostrobin were observed in the first experiment, as well as no interactions among the analyzed factors. In the second experiment the application of pyraclostrobin affected the chlorophyll content positively during the reproductive stage and also affected positively the leaf senescence. In spite of the beneficial effects of the usage of pyraclostrobin on some characters there was no production increase in any of the two simple corn hybrids in the first and second harvests at the Cerrado.
