黄褐天幕毛虫幼虫食叶量观测及防治指标的测定

Observation on feeding quantities of Malacosoma neustria testacea larvae and determination of its control index

该文探讨了荒漠地区黄褐天幕毛虫ＭａｌａｃｏｓｏｍａｎｅｕｓｔｒｉａｔｅｓｔａｃｅａＭｏｔｓｃｈｕｌ－ｓｋｙ幼虫的食叶量。人工模拟不同摘叶强度对胡杨高、径生长量的方差分析及多重比较，Ｆ＞Ｆ０．０１，Ｄ＞Ｄ＊，摘叶３０％、５０％与摘叶１００％之间高、径生长量差异极显著。掌握了胡杨１００ｃｍ标准枝承受的害虫幼虫数及允许受害密度，建立了胡杨幼树单株材积生长量的一元回归方程：Ｙ＝２７．６８１８１＋２５１４２．３５９５７Ｘ。提出天幕毛虫幼虫防治指标：３．４头／１００ｃｍ标准枝，投入防治费用等于挽回经济损失的危害比例为３３．４％，即害虫幼虫危害大于摘叶３３．４％以上，则应立即防治。

In the present paper,feeding quantities of the larvae of Malacosoma neustria testacea in desert area are studied.It is proved that the difference of growth quantities for height and width among 30%,50% and 100% leaf removing is most remarkable,F>F 0.01 ,D>D 。Larval numbers that 100 cm standard branch can bear and the permitted density are known.Simple regression equation for growth quantities of the young individuals of Populus diversifolia is founded as follows:Y=27.68181+25142.35957X.Control index of the larvae is proposed as follows:3.4 individuals/100cm standard branch,i.e.control is needed at once when the harm made by the larvae is larger than that of 33.4% leaf removing.