Researches on Biological Characters of Semanotus bifasciatus

Semanotus bifasciatus (Matsch) is not only a main trunk pest of Cupressaceae plants and a main pest of Cumninghamia lanceolata (Lamb) Hak,but also a kind of quarantine objects in China.This result shows that this pest has one generation within one or two years in Dabie Mountains forests.The imago or the larva hides in the trunks for 173～189 days in winter.In late March of the next year,the imago comes out of the emergence holes by biting the bark and live for 34～47 days.The mean natural living rate is only 6 45%～21 05%. The imago begin to mate in 52 hours and the mated females begin to lay in 18 hours. The hatching period is 16～20 days. The hatching rate is influenced by the temperature in April. The proper mean temperature per five day is 18 6～20 6℃,which makes the hatching rate higher ranging from 74 74% to 82 35%.The larva appears in the mid and late April. The largest eating amount appears in July and August and the eating area is 1 2～1 6 cm 2 each larva per day.The living period of the larva is 132～144 days.The living rate is 14 71%～44 44%. After the middle September,they begin to pupate.The period of the pupa is 12～15 days. They begin to emerge in the late Sep, to the early or mid Oct. The longevity of the adult is 207～236 days.