Interaction of silicon with growth regulating insecticide in the management of fall armyworm Spodoptera frugiperda (J. E. SMITH, 1797) (Lepidoptera: Noctuidae) in corn plants

The objective of this work was to evaluate the effect of sprayed silicon via soil and leaf as well as its interaction with growth regulating insecticide (lufenuron) in the management of Spodoptera frugiperda on corn plants. The trials were carried out in greenhouse and laboratory conditions and consisting of nine treatments with five replicates. In the laboratory, the preference of fall armyworms on detached leaves of corn plants from different treatments was evaluated, as well as the consumption and mortality of this pest. In the greenhouse, the damage caused by the insect on the leaves were evaluated by using a visual scale of injuries proposed by Davis & Williams (1989). In the greenhouse on the control treatment, both the number and weight of the larval were also determined. According to the results, silicon, the insecticide lufenuron and the interaction between silicon and lufenuron did not affect the preference of fall armyworm in a free choice test. The silicon x lufenuron interaction is positive in the management of S. frugiperda when compared to the insecticide only, probably due to a mechanical resistance by the silicon on the leaves surface.