Chitosan Oligochitosan is made of quality chitosan ,which is extracted from shell of crabs. It is an easily-absorbed substance with high solubility after special technological treatment on chitosan. It has excellent water solubility, anti-virus and antibacterial action. It can start and regulate the immunization of plants at gene level and induce anti-virus substance production. Chitosan Oligosaccharide reduces and eliminates the infections of pathogenic agents especially against epiphytes, which are difficult to control. It has no toxicity, no residue and is suitable for non-pollution agricultural ecological system and sustainable development of agriculture.