Time of application, adjuvants and directed spraying effects on the control of Spodoptera frugiperda (Lepidoptera: Noctuidae) in a maize crop.
The larvae phase of Spodoptera frugiperda (Lepdoptera: Noctuidae) has been the major cause of productivity losses in corn crops for many years. The aim of this study was to evaluate the control of S. frugiperda, in the first infestation, during the day and the night time, directing the spray toward the interior of the corn plant and the total area with insecticide spray liquids with and without adjuvant. This work was carried out with two application modes (located and total area), at two periods (8 a.m. and 8 p.m.), with three insecticide spray liquids (with insecticide, insecticide with vegetable oil and insecticide with nonyl phenol) and treatment without application, following a factorial (2×2×3)+1, conducted in a randomized block design. The sowings were proceeded in the seasons of 2012/13 and 2013/14, in which the factors: live larvae (4, 8 and 12 days after application) and dry matter (g plot-1) were evaluated. Better control of the insects was by the nocturnal spray directed to the interior of the corn plants, regardless of the spray liquid used.