Journal of Agricultural Science; Vol. 10, No. 12; 2018 ISSN 1916-9752 E-ISSN 1916-9760 Published by Canadian Center of Science and Education 139 Phytotonic Effect of Fungicide Mixtures Applied at Different Periods in Sweet Corn Estevam M. Costa 1 , Matheus V. A. Ventura 1 , Bruno M. Nunes 2 , Roberto K. Mortate 3 , Mirian Nomura 2 , Jaíza F. R. Chagas 4 , Bruno H. T. Arantes 1 , Marcio M. Bessa 5 , Victor H. Moraes 1 , Rafael M. da Silva 6 , Alessandra P. A. Lima 7 & Marcia R. Oliveira 8 1 Postgraduate Program in Agrarian Sciences-Agronomy, Goiano Federal Institute, Rio Verde, Brazil 2 School of Agronomy, University of the State of Minas Gerais, Ituiutaba, Brazil 3 Postgraduate in Agronomy Sustainability in Agriculture, State University of Mato Grosso do Sul, Cassilandia, Brazil 4 Postgraduate Program in Plant Production, Federal University of Tocantins, Gurupi, Brazil 5 Postgraduate Program in Geography, Paulista State University, Marilia, Brazil 6 Postgraduate Program in Irrigation in the Cerrado, Goiano Federal Institute, Ceres, Brazil 7 School of Agronomy, Evangelical Faculty of Goianesia, Goianesia, Brazil 8 School of Environmental Engineering, Federal University of Tocantins, Gurupi, Brazil Correspondence: Estevam Matheus Costa, Postgraduate Program in Agrarian Sciences-Agronomy, Goiano Federal Institute, Rio Verde, Brazil. Tel: 55-64-98406-8548. E-mail: estevammcosta@yahoo.com.br Received: July 23, 2018 Accepted: September 12, 2018 Online Published: November 15, 2018 doi:10.5539/jas.v10n12p139 URL: https://doi.org/10.5539/jas.v10n12p139 Abstract The fungicides belonging to the chemical groups of strobilurins and triazoles have their contribution to increase the productivity of the crop by a phytotoxic effect. The objective of this study was to evaluate the effects of fungicides at different times on the quality and quality of the spikes. The experiment was conducted at the Universidade do Estado de Minas Gerais and the experimental design was in randomized blocks, with 4 replicates, factorial factorial 3 × 3 + 1, the first factor being composed of 3 combinations of fungicides and the 2 applications (49, 56 and 63 days after sowing-DAS) + 1 witness. The lot was composed of 4 rows spaced 0.45 m and the harvest was done manually at 83 DAS. The height of the plant, the height and the diameter of the glue in the first ear, total mass of ears with and without straw, grain mass per ear, length and diameter of the ears and productivity were evaluated. The data were analyzed by variance and as means compared by the Tukey test. The height of a plant was significantly affected throughout its life in the treatments at 63 days. The series were concentrated by the treatments are a non-spike mass, grain mass per spike and productivity, and pressure levels were loaded when they were performed at 63 DAS. Keywords: ear quality, physiological effect, Zea mays 1. Introduction Sweet corn (Zea mays subsp. saccharata) is a species of olive oil that has high added value and short cycle, since it is harvested green and is destined for human consumption, in natura or after industrial processing, due to its remarkable organoleptic characteristics like flavor sweetness of its grains. Sweet corn is unlikely to have occurred in the wild as a wild breed similar to other types of maize. It can be considered as a product of mutation, followed by domestication, as a new source of sugar would probably not be ignored by the indigenous tribes of various regions of South America, who would use sweet corn as a source of sugar (Parentoni et al., 1990). The sweet character of the corn is due to the presence of mutant genes such as sugary, brittle and shrunken, which in homozygousness lead to a change in plant metabolism, resulting in the blockade of the conversion of sugars into starch in the endosperm (EMBRAPA, 1992). The difference between sweet corn and common corn is in the sugar and starch content of the endosperm. Thus, while common corn has around 3% sugar and between 60 and 70% starch, sweet corn has 9 to 14% sugar and 30 to 35% starch and the superdoce has around 25% sugar and 15 to 25% starch (Luz et al., 2014).