Submitted to: USDA Mexico International Workshop on Agricultural Biotechnology
Publication Type: Proceedings
Publication Acceptance Date: October 24, 2003
Publication Date: December 1, 2003
Citation: Tamez-Guerra, P., McGuire, M.R., Behle, R.W. 2004. Microencapsulation of the major classes of bioinsecticides and techniques for evaluating Bacillus thuringiensis and baculoviruses in Lepidoptera (Microcapsulacion para mejorar la calidad de bioinsecticidas y tecnicas para... In: Galan-Wong, L.J., Elias-Santos, M., Tamez, P., Quintero-Ramirez, R. Quintero-Zapata, I. (Editors). Proceso Biotecnologicos, Primera Edicion. Universidad Autonoma de Nuevo Leon, Mexico. Chapter 12. p. 157-169. Technical Abstract: Commercially, most world-wide available bioinsecticides are based on the bacteria Bacillus thuringiensis (Bt). Bt has to be ingested by the target insect in order to be activated, and usually is active against larvae. Similar to Bt, bioinsecticides based on baculoviruses must be ingested to infect larvae. Because they must be ingested, Bt and baculovirus formulated products are designed to be applied where the larvae usually feed, and might contain phago-stimulants. Most of these formulations, however, suffer from a rapid loss of residual insecticidal activity because the active agent is degraded by sunlight, washed-off by rain, or is distasteful to the target insect. Several ingredients, when tank mixed as adjuvants, have shown promise in protecting Bt from adverse environmental conditions. A spray dry process has been used to produce microgranulated formulations with Bt or baculovirus. Microgranules include protective ingredients (natural polymers), which provided solar protection when tested as adjuvants. This chapter described the microencapsulation technology, which combines the active agent with the protective ingredients in order to prevent disassociation during the mixing and application. The chapter also describes the bioassays, tested against species of Lepidopteran larvae, to evaluate the efficacy of the formulation based on stability after solar radiation and rain exposure.