Abstract: The paper determined the biomass and the productivity of Beefwood ( Casuarina equisetifolia) shelter belt in Pingtan island, Fujian, by investigating the tree layer and the litter layer using the method of stadard tree within stem step.According to the materials,we established the regression model for single tree's various organ's dry weight from Beef wood shelter belt.The relationship appeared very significant.The paper also studied the biomass distribution, struture, and increasing trends and judged the ecosystem quality and productivity of the shelter belt . The result showed that the average biomass in Beefwood shelter belt was 141.17t·ha^-1, and the annual net primary productivity was 24～396t·ha^-1, in which the stem's biomass accounted for 61～8percent of the total output mass of the tree,the root biomass was 19.02pecent,and the leaf was 7.74percent.

Key words: Frankliniella occidentalis, imidacloprid, phoxim, emamectin benzoate, resistance selection, resistance risk, resistance stability.