Development of novel betabaculovirus (HycuGV-Hc1) as a biopesticide (HycuGV-TR61) and its efficacy on the fall webworm, Hyphantria cunea Drury (Lepidoptera: Erebidae) larvae

Abstract

Background The aim of this study was to develop an oil formulation from a local betabaculovirus. Hyphantria cunea Drury (Lepidoptera: Erebidae) granulovirus (HycuGV-Hc1) was isolated from the infected larvae to test its efficacy on the pest. The oil formulation was prepared by mixing the viral suspension with sunflower oil and some adjuvants and named HycuGV-TR61. Crude virus and the formulations were carried out on third instar H. cunea larvae using 1 × 104–8 OBs /ml concentrations and were exposed to temperatures (28, 35, and 42 °C) and UV-B light at different periods (0, 1, 3, 5 h). Results The mortality rate, which was 50% at the lowest concentration (1 × 104 OB/ml), reached 99.86% at the highest concentration (1 × 108 OB/ml). LC50 values of fresh and old forms were calculated as 0.64 × 104 and 0.87 × 104 OBs/ml, respectively. Application of shelf life showed that there was non-significant change in the pathogenic activity of the formulation with time. In the experiments, it was observed that the activity decreased as the temperature and time of exposure increased. Significantly difference in larval mortality was observed when fresh and old formulations were exposed to 0, 1, 3 and 5 h to UV-B, (old: 96.7, 86, 80 and 60%; fresh: 97.1, 90, 85 and 62%, respectively). Conclusions The results revealed superior aspects of HycuGV-TR61, which was developed as a local viral biopesticide, its resistance to abiotic factors and its potential to be used in pest control.