Utilização de modelos matemáticos para estimar a interferência e nível de dano econômico de papuã em híbridos de milho

Abstract

The identification of the competitive ability of corn hybrids and the level of economic damage (LED) caused by the alexander grass (Urochloa plantaginea) becomes important for the adoption of the integrated management of this weed. The objective of this study was to evaluate the interference and LED of alexander grass and maize hybrids. The treatments were composed of maize hybrids, Syngenta Status - VIP 3, Syngenta SX8394 - VIP 3, Pioneer - P1630H, Pioneer - 30F53 YH and Dow -135021 and 12 alexander grass populations for each hybrids. To describe the relationship between corn grain yield loss and explanatory variables, plant population (PP), dry mass of the aerial wall (DM), soil cover (SC) and leaf area (LA) model of the rectangular hyperbola. LED determination was performed using grain yield, control cost, corn price and herbicide efficiency. The PP presents a better fit to the model of the rectangular hyperbole than the AF, CS and MS, and grain yield losses due to weed interference can be satisfactorily estimated by this model. The hybrids, Pionner - 30F53 YH and Pionner - P1630H presented higher competitiveness and higher LEDs. The sowing of the Pioneer - P1630H, Pioneer - 30F53 YH and Dow - 135021 hybrids increases the level of economic damage, justifying the adoption of alexander grass control measures at higher densities. Increases in grain yield, maize price, herbicide efficiency, and reduction in control costs decrease LED values, justifying the adoption of control measures at low alexander grass densities.