Effect of temperature and two drying processes on the insecticidal activity of a nucleopolyhedrovirus of Spodoptera frugiperda

 

J.E. Camacho, M.I. Gómez and L.F. Villamizar

 

 

The effectiveness and potential use of Baculovirus for controlling different insect pests have been shown in several studies. However, their evaluation under field conditions has presented inconsistent results, possibly because of the deleterious effect of environmental conditions such as temperature. Considering the potential of a Colombian isolate of Spodoptera frugiperda nucleopolyhedrovirus SfMNPV003 for developing a biopesticide, the objective of this study was to evaluate the effect of temperature and two drying processes over viral insecticidal activity, in order to use process conditions that allow to design efficient formulation. The nucleopolyhedrovirus, was exposed to temperatures between 30°C and 60°C for 30, 45, 60, 120 and 180 minutes. Processes tested were oven drying and spray drying in fluid bed, evaluating pH, moisture content, content of microbial contaminants, viral concentration, yield and insecticidal activity (LC50) of dry virus. The insecticidal activity of the virus decreased when it was exposed to temperatures above 50°C. Oven drying process was selected for presenting the highest yield, also because it did not affect the virus pathogenicity and allowed to obtain a dry powder with a lower microbial contaminants content.