Preliminary Study On Environment-harmonizing Control Techniques Of Seabuckthorn Carpenter Worm (Holcocerus Hippophaecolus)

Seabuckthorn carpenter worm (Holcocerus hippophaecolus Hua, Chou, Fang et Chen) 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.In this article, biological and ecological characteristics of seabuckthorn capenter were expatiated and a lot of field and indoor experiments were done based on the characteristics mastered to determine the effective way of controlling the worm. Chemical control and biological control were involved in the environment-harmonizing control techniques.The results showed that some methods, including chemical spray and chemical irrigating, are invalid. The mortality rate in corresponding experiment was no more than 20%. While fumigating with aluminium phosphide is much more effective and the highest mortality rate is 98.95%. Fumigating is proved to be a simple, convenient and low cost control method, especially in the intensively managed forest.Simultaneously, experiments with Steinernema carpocapsae were done. The indoor experiments got the highest mortality rate of 92.5%, but the field experiment didn't get a satisfying result because of the impact of natural temperature, humidity and the way in which we did the experiment. Further study is needed to show how to make better conditions for Steinernema carpocapsae to fully exert its control ability.We also found some dead larvae parasitized by a kind of fungus which we identified to be Verticillium sp.. Laboratorial experiment with this fungus got a mortality rate of 46.67%.The indoor experiment result predicted a prosperous future for controlling seabuckthorn carpenter with nematodes and fungi.