Abstract:

Crude protein, crude fat, crude fiber, starch, reducing sugar, total soluble sugar, free amino acids, four major inorganic elements (Na，K，Ca，Mg) and four trace elements (Fe，Cu，Mn，Zn) in the phloem of healthy and a blue stain fugus-infected Pinus armandii, and in the excrement of Chinese white pine beetle (Dendroctonus armandi) were measured. The results showed that the utilization efficency of nutrition by D. armandi was: reducing sugar>crude fat> total soluble sugar> crude fiber> starch> crude> protein. There were 17 free amino acids in the phloem of P.armandii, among which nine are requaired by D.armandi. In D.armandi’s excrement, K content was the highest among the major elements of Na,K,Ca,Mg, and Fe content was higher that of the other trace elements probably because it has great influence on the growth of blue stain fungus. Meanwhile, the blue stain fungus was able to decompose the nutrients from the phloem to the xylem, which provided more nutrients for the bark beetle, thus accelerating the weakness and death of the attacked host tree.

Key words: Dendroctonus armandi, Pinus armandii, phloem, blue stain fungus, utilization of nutrition