铁杉球蚜的生物学及空间分布

通过对铁杉(Tusga chinensis Pritz)-云杉(Picea retroflexac Mast)、铁杉-华山松(Pinus armardi Franch)、云南铁杉(Tusga domosa Eichler)-槭树(Acer mono Maxim)-桦木(Betula platyphylla Suk)四川主要铁杉林类型中铁杉球蚜Adelges tsugae Annand林间定株、种群随机抽样、室内饲养研究表明,铁杉球蚜在四川1年发生2代(越冬代和第1代),世代重叠,成虫营孤雌生殖。越冬代从4月上旬至第2年的4月下旬,产卵盛期在5月下旬,平均产卵量为15.58粒,1龄若虫具有滞育越夏习性;第1代从12月下旬至8月中旬,产卵盛期在3月下旬,平均产卵量为67.37粒,并可产生有翅成虫,但无转主危害现象。种群的发育与温度有相关性,温度高林分种群发育进度快于温度低林分。该虫的危害与生境有一定相关性,铁杉针阔混交林危害重于铁杉针叶林;同一树冠不同层次之间、不同方位之间危害程度差异不显著;当年受害严重的树株第2年受害不严重。

Biology of the hemlock woolly adelgid, Adelges tsugae, and its spatial distribution

Both laboratory observation and field sampings of the hemlock woolly adelgid (HWA), Adelges tsugae Annand (Hemiptera: Adelgidae) among three foret types(Tusga chinensis Pritz-Picea retroflexa Mast; Tusga chinensis Pritz-Pinus armardi Franch;Tusga domosa Eichler-Acer mono Maxim-Betula platyphylla Suk) showed that there were two parthenogenetic generations overlapping on hemlock in Sichuan Province. The first nymphs of overwinter generation aestivated throughout the summer and the winged adults of first generation appeared on hemlock in June,but did not migrate to spruce. The overwinter generation developed from early April to late April of next year with peak oviposition in late May (average 15.58 eggs per female). The first generation developed from late December to mid Augest with peak oviposition in late March(average 67.37 eggs per female). HWA development was positively correlated with temperature, faster in warmer sites. HWA infestation was also related to forest type, more severe in hemlock forests mixed with broadleaf hardwood. Within a tree, there was no difference in HWA infestation at significant statistical levels among cardinal directions.