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
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.
