Simplified and cool texturing diets for in vivo inoculation of Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV)

Abstract

The inoculation of viral entomopathogens in vivo requires study of each pathosystem. Several factors interfere in the cost of production and consequently in the availability of virus-based formulations. For the Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV), employed in the management of the fall armyworm Spodoptera frugiperda, factors such as host cannibal habit, temperature, and artificial diet of viral inoculation are important to research. In this work we propose to evaluate a diet based on textured soy protein, without heating during preparation, for viral inoculation and an artificial diet of simplified composition, based on wheat germ, to complete the feeding of larvaes during the stage of viral inoculation in groups of insects. S. frugiperda larvae were inoculated with SfMNPV virus in two diets: an artificial diet similar to that of mass rearing of the host and texturized soy protein at the following temperatures and respective ages: at 25 °C at 6 and 8 days after hatching and 31 °C at 4 and 6 days after larvae hatching. And, subsequently, viral inoculation was evaluated in a group of 300 larvae under different incubation times and temperature conditions, complementing feeding at this stage with a diet of simplified composition. The results show that it is possible to inoculate viruses without loss of viral polyhedra production in a textured soy protein-based diet and supplement the larvae diet with an artificial diet of simplified composition to complete the viral infection stage in groups of infected insects.