黄杨绒蚧的生物学特性及卵期预测预报

黄杨绒蚧Eriococcus abeliceae Kuwana是危害园林树木的重要害虫之一。该蚧在西宁地区1年发生1代,以2龄若虫在树干裂皮缝中越冬。翌年3月下旬2龄若虫蜕皮变为3龄若虫,开始为害,雌虫5月上旬开始产卵,卵期18~23d,每雌虫产卵量134~424粒,平均287粒。6月上旬卵开始孵化,孵化率100%。雌虫3龄,雄虫2龄。在室内自然变温条件下,对黄杨绒蚧卵的发育起点温度和有效积温进行测定。结果表明:卵发育起点温度12.98℃,有效积温39.03日.度;预测式为N=(39.03±2.66)/T-(12.98±0.18)。

Biological characteristics and ovipositing time forecast of Eriococcus abeliceae

Eriococcus abeliceae Kuwana is one of the most important pests attacking many kinds of garden trees. It occurred one generation per year in Xining, and overwintered as 2nd instar nymphs in bark crevices. It began to damage trees when 2nd instar nymphs developed into 3rd instar nymphs in late March of next year. Adult females started to lay eggs in early May, and the duration for eggs was 18-23 days. The fecundity was from 134 to 424 eggs per female with the average of 287 eggs. Eggs began to hatch in early June and the hatching rates was 100% . It was found 3 instars in females and 2 instars in males. The developmental threshold temperature and effective accumulated temperature for egg were determined under natural temperature in lab. The results showed that the threshold temperature was 12.98℃ and the effective accumulated temperature was 39.03 degree-day. The predicting equation for the rate of development was N = (39.03 ± 2.66)/T-( 12.98 ± 0.18) .