Sustainable Silage Maize Integrated Protection against the European Corn Borer Ostrinia nubilalis and the Corn Earworm Helicoverpa armigera Employing the Farm Irrigation System

Abstract

Silage corn is an important source of feed in animal husbandry, often affected by the feeding action of diverse corn borers that can compromise harvest quality and quantity. According to the need to reduce the use of chemical insecticides, the main purpose of this study was to evaluate the efficacy of different IPM programs comparing microbial (Btk and baculovirus) and chemical control methods, alone or combined, against O. nubilalis and H. armigera. Assessments were based on counting the number of larvae, inspecting plants superficially and inside the stem, and estimating the derived damages. All tested products proved to be effective in containing the density of these lepidopteran species, with microbial control agents having comparable efficacy in respect to the reference chemical substances (lambda-cialotrina and chlorantraniliprole), even if periodic treatment repetition was required to ensure over-time protection until harvest. Both Btk and HaNPV were successfully applied by the irrigation system during flowering and fruit development periods, when plant height did not allow the use of a tractor-mounted spray bar. This biocontainment approach appears to be sustainable and technically compatible with farm needs.