Implementation of quality control techniques for the production of a biopesticide based on the granulovirus Phthorimaea operculella PhopGV

Abstract

The Guatemalan potato moth Tecia solanivora (Lep.; Gelechiidae) is one of the most limiting pests of this crop in Venezuela, Colombia and Ecuador and its control through the use of chemical insecticides has not been very effective. Its biological control with the granulovirus Phthorimaea operculella (PhopGV) has been one of the principal components of its management in Colombia and other Andean countries. Corpoica has a plant, registered through the Colombian Agricultural Institute, for manufacturing a biopesticide based on this virus. Given the importance of confirming product quality, the objective of this work was to standardize and implement quality control tests during the manufacturing process. Virus identity and concentration, physical-chemical characteristics of the product and biopesticide efficacy were established as critical parameters; methodologies for evaluating these parameters were then standardized and implemented in the production process. Virus identity was confirmed as P. operculella by microscopic, immunological, and molecular techniques. To control viral concentration, lethal viral concentrations were determined and acceptable limits for this variable were established. The biopesticide was elaborated based on these results.  The lethal concentration (LC₉₀) was 8 x 105  occlusion bodies (OB).mL-1  and based on this result, the final product was adapted to give a concentration of 10⁵  OB.g-1. Three batches of the product were manufactured and quality control showed low variability, indicating the repeatability of the process. Mean product characteristics were concentration 105  OB.g-1, moisture content 0.57%, voluminosity 0.93 mL.g-1, pH 9.52 and efficacy 97.25%.