Impact of fall armyworm (Lepidoptera: Noctuidae) in the performance of corn crops associated to insecticides in lowland environment.
Brazil, in lowland environment, corn has the potential for crop rotation with irrigated rice to minimizing infestations of red rice. The use of resistant cultivars associated to the use of insecticides are the main methods of control of the fall armyworm, Spodoptera frugiperda (Smith, 1797) (Lepidoptera: Noctuidae). However, there are lack of field studies that assess the crop's production chain. The objective of this study was to evaluate the performance of corn cultivar, the conventional AG 9045 and the isogenic AG 9045 PRO2 Bt on the control of S. frugiperda, as well as to analyze the cost of production in the lowland environment. The cultivars were sown in the 2014/2015 and 2015/2016 harvests with adopted spacing of 0.7 meters and length of 5 meters. The application of insecticides was performed when the index of 10% of plants attacked by S. frugiperda was reached. Percentage (%) of attacked plants, corn productivity (kg ha-1) and cost of production (US$ ha-1) were evaluated. In the final analysis, the AG 9045 PRO2 isogenic Bt in conjunction to the chlorfenapyr+zeta-cypermethrin treatment show better efficiency on the control of S. frugiperda caterpillars, by a combination of two different control methods and active principles in the control of S. frugiperda, higher productivity indexes (3,155.58 kg ha-1) and profitability (-112.08 US$ ha-1).