Study on the Dead Pine of Pinus yunnanensis in Occurrence Area and Non-occurrence Area of Bursaphelenchus mucronatu

The investigation result of 400 dead trees of Pinus yunnanensis reveals that Monochamus alternatus,Blastophagus piniperda and Pissodes yunnanensis are the main trunk borers causing death of the pine in occurrence area and non-occurrence area of Bursaphelenchus mucronatus.The main attacking way to the pine is the complex destruction of the three pests.In the complex destruction,one of the three pests always appears as dominant species.After a comparison of the destruction rate of the 3 pests,the longhorn beetle Monochamus alternatus can carry and spread the nematode Bursaphelenchus mucronatus.In the paper a control measure is proposed in accordance with the complex destruction of the three pests.