Dual-shell microencapsulation enhances nucleopolyhedrovirus stability and insecticidal activity

Insect viruses are a type of environmentally friendly and safe microbial insecticide. However, they are prone to deactivation in the environment due to exposure to light. In this study, to enhance the insecticidal activity and UV resistance of the Spodoptera exigua nucleopolyhedrovirus (SeNPV), chitosan and polydopamine were selected as embedding materials, A chitosan-dopamine SeNPV (CS / PDA-NPV) microcapsule was successfully developed, and characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and Zeta potential analysis. The results show that CS / PDA-NPV microcapsule exhibit a well spherical morphology with a particle size range of 3-5μm. Compared to free SeNPV viruses, CS / PDA-NPV microcapsule exhibit enhanced thermal stability. After UV treatment, the insecticidal activity of the virus microcapsule was 1.5 times higher than that of the non-encapsulated viruses, demonstrating that the chitosan-polydopamine bilayer structure provides effective UV shielding for SeNPV.