A Study of Bionomics and Control on Pissodes sp.(Coleoptera,Curculionidae)

The damage caused by Pissodes sp was lately recorded in Kunming district,Yunnan Province.The larvae of the pest feed on 2~3 year old branches of yunnan pine(Pinus yunnanensis Franch).The altitude of pest distribution is between 2200~2600 m above sea level in Kunming district.It has one generation per year,and overwinters by old larvae in branches of the host.It begins to pupate in the last ten days of March.The adults begin to emerge in the 1st ten days of May,complement nutrition on newly growing branches of the host,and lay eggs on 2~3 year old branches from June to August.The larvae begin to hatch in the last ten days of June.The natural enemy of the pest found out is a species of Bracon(Bracon sp,Hymenoptera,Braconidae),and the parasited rates of pissodes.was 16% to 330%.The technics of control were tested from 1995 to 1997.The result showed that the best suitable control stage is in the 2nd to last ten days of April,and the effect of control is good.