Studies On The Pathogeny Causing Disease To Monochamus Alternatus

Monochamus alternatus is a serious forest pest which not only attacks pine trees but also drills in the host tree stems and branches, and it is also a major vector of pine wood nematode (Bursaphelenchus xylophelus).It has already endangered our country's pines seriously. Microsporida is a kind of unicellular protozoa which parasitizes in the living cell specially and it is a kind of important entomopathogen.It's efficient to control the insect populations persistently and it's safe for the enviroment as a bio-pestcide. It can cause insect's disease to prevail through propagate or transmit vertically and levelly.So it is one of the important factors which restricts insect's populations in the nature. But there is no report using Microsporida to control the longhorn beetles both at home and abroad. Beauveria sp is a kind of important biological control agent which has been widely applied to control insect pest. It is for some years to control M. alternatus by Beauveria sp. But it is limited to control pest because only spore powder or liquid can be used.This research includes two parts mainly: 1)Microsporida was extracted from Monochamus alternatus and its characteristic and ultrastructure were observed in order to define its categorised position. And its epidemic situation was investigated in the field in order to provide the theory and practice basis for biological control of the Monochamus alternatus. 2) Extracting toxic proteins to M. alternatus from Beauveria sp will reveal the mechanism how the fungi infect their host from the view of biochemistry and molecular biology and it is also the foundation for cultivating anti-longhorn beetles trees .Through observing its exterior characteristic and ultrastructure we think this kind of Microsporida is belong to Nosema and name it Microsporida of Monochamus alternatus (Nosema alternatus Zhang ) Field investigation prove there are Microsporida infection to the Monochamus alternatus in different places. And Microsporida which exist in the nature extensively is one of the restriction factors of the insects .Twelve representative Beauveria sp strains were choosed from the collections in our laboratory. The result of bioassy for 12 strains shows that Bb6 and Bb8 have high toxic to Monochamus alternatus under 25℃, Bb6 and Bb8's LC50 is3.34×10~7spores/ml and 5.76×10~7 spores/ml; There are significant difference in zymograms of esterase isozymes between the host larvae infected with Bb6 and the control. The zymograms of the treated increase band E5, and the color of the band E1, band E2, band E3, bandE4 is heavier than the...