Submitted to: Journal of Economic Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/15/1999
Publication Date: 4/15/2002
Citation: TAMEZ-GUERRA, P., MCGUIRE, M.R., BEHLE, R.W., HAMM, J.J., SUMNER, H.R., SHASHA, B.S. SUNLIGHT PERSISTENCE AND RAINFASTNESS OF SPRAY-DRIED FORMULATIONS OF THE ANAGRAPHA FALCIFERA BACULOVIRUS. JOURNAL OF ECONOMIC ENTOMOLOGY. 2002. v. 93(2). p. 210-218. Interpretive Summary: Insect pests are generally controlled by the application of synthetic chemical pesticides. The chemical may affect non- target organisms or otherwise cause undesired effects in the environment. Alternatives to chemicals are currently under development and include microorganisms that infect and kill a very small number of insect pest species. Viruses are one such group of microorganisms that are just entering the pest control market. However, the length of time the viruses stay active in the field after application is unacceptable. Our manuscript reports the use of abundant farm commodities as materials that can be used to formulate the viruses to improve the residual activity. A novel method was developed to combine the virus with the protective materials. We demonstrated in the laboratory that corn flour and lignin can protect viruses from artificial light and rainfall compared with unformulated virus. This information should be useful to scientists conducting work on mechanisms that affect virus persistence and to companies interested in developing viruses as biopesticides.
Technical Abstract: Nuclear polyhedrosis viruses such as the one isolated from the celery looper Anagrapha falcifera (Kirby) (AfMNPV), have the potential to be successful bioinsecticides if improved formulations can prevent rapid loss of insecticidal activity from environmental conditions such as sunlight and rainfall. We tested 16 spray-dried formulations of AfMNPV to determine the effect of different ingredients (e.g., lignin, corn flour, etc.) on insecticidal activity after simulated rain and simulated sunlight (at Peoria, IL) and natural sunlight exposures (at Tifton, GA). The most effective formulation contained pregelatinized corn flour and potassium-lignate, which retained more than half of its original activity after 5 cm of simulated rain, and almost full activity after 8 h of simulated sunlight. In Georgia, formulations made with and without lignin were compared for persistence of insecticidal activity when exposed to natural sunlight. In addition, the effect of fluorescent brighteners as formulation components and spray-tank additives was tested. Results showed that the formulations with lignin had more insecticidal activity remaining after sunlight exposure than formulations without lignin. The inclusion of brighteners in the formulation did not improve initial activity or virus persistence. However, a 1% tank mix significantly enhanced activity and improved persistence. Results demonstrated that formulations made with natural ingredients could improve persistence of virus-based biopesticides.