Chemical And Entomogenous Fungi Control Techniques Of Seabuckthorn Carpenter Worm (Holcocerus Hippophaecolus)

Holcocerus hippophaecolus is one of the borers attacking seabuckthorn, which mainly harms the roots and stems of hosts. In recent years, the outbreaks of this pest in Liaoning, Inner Mongolia, Shanxi and Ningxia provinces made lots of seabuckthorn trees dead and reduced their ability to conserve soil and water, furthermore, this caused a serious economic loss for seabuckthorn industry.The downtree transferring characteristics of larvae hatched in the new year were investigated in this paper. The result showed, from September 1st to October 22th, the great majority of larvae transferred between 9 a.m. and 4 p.m., the few minority of larvae transferred before 8 a.m. and after 8 p.m.. The larvae crawled out from the frass site , transferred down along the trunk to earth ground, then digged into the layer of soil, finally cached in a fitting site of cortex.With the use of downtree transferring characteristics, prevention tests were conducted. The result showed, By drawing a circle 4cm wide pesticide ring around the trunk with a brush in the height of 30cm to 40cm from the ground, the mortality of larvae reached 100 percent after 5 days, and can still reach 80 percent above after 30 days.The indoor experiment results of the pathogenicity of entomogenous fungi to larvae telled that under 25℃and concentration of 1×106conidia per ml,the 3-instar larvae was infected most quickly by B01(Verticillium Nees) and the infection rate was the highest, on the ninth day after being dealt with the larvae was firstly infected, on the 24th day the infection rate reached the highest 40 percent. As the temperature turned higher or lower than 25℃,the larvae was infected slowly. The bigger the instar was,the larvae were lessly infected.