In order to understand the occurrence and development of Semanotus bifasciatus （Motschulsky）, a borer insect of Platycladus orientalis in parts of northern and eastern China and to improve its prediction, the develo...In order to understand the occurrence and development of Semanotus bifasciatus （Motschulsky）, a borer insect of Platycladus orientalis in parts of northern and eastern China and to improve its prediction, the developmental threshold temperature （C1） and effective accumulated temperature （K） of S. bifasciatus were determined under conditions of constant and variable temperatures. The results show that under constant temperatures the value of C1 has a range of 8.90±1.77℃and the value of K lies between 95.19±13.14 degree-day for eggs; the values for larvae are C1= 13.26±3.06℃ and the number of degree-day is K 2,885.07±187.87 degree-day; for pupae the ranges are C1 = 8.93±2.49℃ and K= 131.20±25.63 degree-day. Under the condition of ambient temperatures, the values for eggs are C1= 17.33±1.24℃ and K= 70.79±8.99 degree-day. It is suggested that S. bifasciatus adults over-winter in a state of dormancy, not at a diapause. Warm winter may accelerate the life cycle ofS. bifasciatus. Equations can be used to predict an early occurrence ofS. bifasciatus.展开更多
Based on an analytical TCT-GC/MS method, volatile compounds of branches of Platycladus orientalis under three physiological states （healthy, weak and baited trees） were analyzed. The results showed that α-pinene, ...Based on an analytical TCT-GC/MS method, volatile compounds of branches of Platycladus orientalis under three physiological states （healthy, weak and baited trees） were analyzed. The results showed that α-pinene, β-phellandrene, 3-careen, limonene and thujopsene were released under all three physiological states. There were other kinds of volatiles released from branches of weak P. orientalis trees, such as camphene, γ-terpinene, （＋）-4-carene and cedrene, but these four volatiles compounds were not released from the branches of healthy P. orientalis. Volatile components from the physically damaged branches of P. orientalis had changed. β-terpinene, mycrene, isocaryophillene and caryophyllene were identified in both healthy and weak branches of P. orientalis. Only cedrene was identified in the baited wood. Electroantennogram （EAG） tests were conducted with nine volatile compounds from the branches of P. orientalis. Antennnae of male and female Semanotus bifasciatus （Motschulsky） were highly sensitive to these nine volatile compounds. Cedrene elicited the strongest response, whereas β-terpinene the lowest. Males and females showed no signifi-cant difference in their EAG responses to the nine volatile compounds.展开更多
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 t...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.展开更多
文摘In order to understand the occurrence and development of Semanotus bifasciatus （Motschulsky）, a borer insect of Platycladus orientalis in parts of northern and eastern China and to improve its prediction, the developmental threshold temperature （C1） and effective accumulated temperature （K） of S. bifasciatus were determined under conditions of constant and variable temperatures. The results show that under constant temperatures the value of C1 has a range of 8.90±1.77℃and the value of K lies between 95.19±13.14 degree-day for eggs; the values for larvae are C1= 13.26±3.06℃ and the number of degree-day is K 2,885.07±187.87 degree-day; for pupae the ranges are C1 = 8.93±2.49℃ and K= 131.20±25.63 degree-day. Under the condition of ambient temperatures, the values for eggs are C1= 17.33±1.24℃ and K= 70.79±8.99 degree-day. It is suggested that S. bifasciatus adults over-winter in a state of dormancy, not at a diapause. Warm winter may accelerate the life cycle ofS. bifasciatus. Equations can be used to predict an early occurrence ofS. bifasciatus.
文摘Based on an analytical TCT-GC/MS method, volatile compounds of branches of Platycladus orientalis under three physiological states （healthy, weak and baited trees） were analyzed. The results showed that α-pinene, β-phellandrene, 3-careen, limonene and thujopsene were released under all three physiological states. There were other kinds of volatiles released from branches of weak P. orientalis trees, such as camphene, γ-terpinene, （＋）-4-carene and cedrene, but these four volatiles compounds were not released from the branches of healthy P. orientalis. Volatile components from the physically damaged branches of P. orientalis had changed. β-terpinene, mycrene, isocaryophillene and caryophyllene were identified in both healthy and weak branches of P. orientalis. Only cedrene was identified in the baited wood. Electroantennogram （EAG） tests were conducted with nine volatile compounds from the branches of P. orientalis. Antennnae of male and female Semanotus bifasciatus （Motschulsky） were highly sensitive to these nine volatile compounds. Cedrene elicited the strongest response, whereas β-terpinene the lowest. Males and females showed no signifi-cant difference in their EAG responses to the nine volatile compounds.
文摘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.
