Abstract: The analysis showed that 58 species of trees,short-trees and shrubs in Neilingding Island of Guangdong Province were damaged byM.micrantha,of which,woody trees accounted for 67%.Short-trees and sunny shrubs were damaged most seriously,followed by the communities with low canopy density consisted of only 2 dominant species,and those with high canopy density consisted of 5 or 6 dominant species.The coverage of M.micrantha mainly related to the vertical structure of plant communities.The taller the community height and the more the synusia,the lesser was the coverage of M.micrantha.The damaging ratio mainly related to species diversity and community density.The higher the species diversity and community density, the lower the damaging ratio was.The damaging degree mainly related to the coverage of other liana.The more the coverage of other liana,the higher was the damaging degree of M.micrantha.

Key words: Spodoptera litura, Larval instar, Nuclear polydedrosis virus, Disease epizootic, Distribution of disease time, Complementary log log model