Immobilizing bifenthrin on wood for termite control

Termites are world-wide pests causing significant losses to annual and perennial crops, as well as damages to wooden components in buildings. Although various chemical, physical, and biological methods have been explored to prevent termite attack on wooden structures, new guiding principles are still needed for environmental protection. In this study, by combining the effective chemical control of bifenthrin and photo-immobilization technique of biomolecules, we developed chitosan as a carrier to embed bifenthrin, which was then immobilized by ultraviolet treatment on the surface of wood (Cunninghamia lanceolata). The immobilized bifenthrin embedded in the photoactive chitosan was characterized by Fourier transform infrared spectroscopy (FTIR), C.H.N analysis, ultraviolet, and fluorescence measurements. The surface structures and biological activity were examined by scanning electron microscopy (SEM), atomic force microscope (AFM), electron spectroscopy for chemical analysis (ESCA), and bioassays. The results indicated that the immobilized bifenthrin can be well protected from free and non-controlled releasing, and has a long-term stability allowing high efficiency against the termite at a dose of 2.5 μg/cm2. This study provides a novel and environmentally-benign technique for the termite control by photo-immobilizing the bifenthrin-embedded chitosan on the surface of C. lanceolata. This technique may be used in combination with the traditional methods for effective termite control.