啄木鸟对黄斑星天牛自然控制作用的林间调查

A Forestry Investigation on the Natural Control of Anoplophora nobilis Ganglbauer by Woodpecker

根据 1 996～ 1 998年在陇西县的野外多点调查 ,表明黑枕绿啄木鸟、大斑啄木鸟均为黄斑星天牛的优势天敌鸟类 ,有效控制面积为 31 33hm2 ,捕食率达 5 4 %～ 60 %。3年间虫口密度由1 5 .5头 /株降至 3.2头 /株 ,其中 ,嗜食类杨树寄主的虫口密度由 2 6.6头 /株降至 5 .1头 /株 ;非嗜食类杨树寄主的虫口密度由 6.5头 /株降至 1 .7头 /株 ;共挽回直接经济损失 65 3.7万元 ,基本实现“有虫不成灾”的良好控制效果。同时 ,也客观地反映出啄木鸟防治能力有限 。

Field studies during 1996～1998 in Longxi County confirmed that both Picus canus Gmelin and Dendrocopos major Beicki were dominating natural enemy birds of Anoplophora nobilis Ganglbauer in 3 133 hm 2 populus forest,and 54%～60% of the scale population of the larvae and egg of longicorns borers on the sampling trees were attacked by them.In three years,the average population density of A.nobilis Ganglbauer was reduced from 15.5/tree to 3.2/tree, and then from 26.6/tree to 5.1/tree on the preferable host,from 6.5/tree to 1.7/tree on the non preferable host 6.537 million yuan was saved. Although it was possible that the population density of A.nobilis Ganglbauer would be under the ecoconomic injury level 2/tree by the biological control,the limitations were revealed.