THE EFFECT OF ULTRAVIOLET RADIATION ON THE PLANT BIOPESTICIDE, Cryptophlebia Leucotreta GRANULOVIRUS

摘要

Cryptophlebia leucotreta granulovirus (CrleGV-SA) is pathogenic to the common citrus pest the false coddling moth, Thaumatotibia leucotreta. It has been formulated into a commercial biopesticide, Cryptogran produced by River Bioscience South Africa. The virus has a proteinaceous crystalline occlusion body (OB) largely composed of granulin that protects the nucleocapsid. Previously we have shown that the virus can be enumerated by scanning electron microscopy (SEM). The major setback with the use of Baculoviruses as biopesticides is their susceptibility to the ultraviolet component of sunlight. Studies have shown that some Baculoviruses can be greatly reduced in as little as 48 hours by UV exposure. The UVA and UVB components of sunlight are known to be most destructive to biological organisms. Previous studies have focused on the biological effect of UV alone on the Baculoviruses. To date no publication has reported the effect of UV exposure on the structure and virulence of CrleGV and the effectiveness of the occlusion body as a UV protectant. In this report we will show the effect of UV radiation on the structure and infectivity of CrleGV-SA using Raman spectroscopy, scanning electron microscopy (SEM) as well as a biological assay known as the droplet assay.