Pyemotes sp.and Scleroderma guani were used to control the larvae of Semanotus bifasciatus.The results as follows:(1) the suitable control time of Pyemotes sp.was from early April to early May.The reason was that in this time,the larvae of S.bifasciatus were young and not bored into xylem that was so easy to be parasitized by Pyemotes sp.With the parasitic rate 80% in average.Indoor experiment showed that the Pyemotes sp.had the same tropism selection to every instar for the host,but the parasitic rate was higher in low instar than other instars.(2)Using Scleroderma guani to control S.bjfasciatus,the suitable time was from mid May to mid June,the optimal ratio of host and parasite was 1∶1.Indoor experiment showed that Scleroderma guani had strong tropism toward middle-aged and elder larvae,the parasite linger around them and choose suitable position on hosts where they could lay eggs successfully.This behavior showed that Scleroderma guani had strict selectivity for their hosts.In experiment,the authors found a phenomenon that in one trap wood,both the Pyemotes sp.and Scleroderma guani could be found at the same time,they themselves did not affect each other and otherwise they could increase the parasitic rate for host.So,the authors suggested that in practice to control pests especially for boring pests,the Scleroderma guani and Pyemotes sp could be used at the same time.
