榆绵蚜的生物学研究

利用振动试验台，进行了苹果运输振动损伤的模拟试验。结果表明：当振动频率为２Ｈｚ，加速度＞１．０×９．８ｍ／ｓ２时，包装箱内与各层包装箱的加速度均大于振动台面的加速度，且由底层向顶层递增；包装箱内损伤体积中层＞底层＞顶层；这两种工况的损伤体积均随加速度的增加而线性增加；加缓冲材料可使损伤体积减少５０％．

Biological Study of Eriosoma lanuginosum dilanuginosum (Zhang)

The researches based on artificial inoculation and field investigation for the frist time indicate that pear ( Pyrus spp.) is secondary host of Eriosoma lanuginosum dilanuginosum (Zhang,1980).The life history belongs to heteroceous holocycle type.From the midde of May to the middle of June alate fundatrigeniae fly and migrate to the pear and apterous viviparous female do the damage to the thin root of the pear.From the begining of October to the beginning of November sexuparae fly and migrate to the elm ( Ulmus spp.) and produce the sexuales of female and male.After mating the female sexuales lay an egg.The eggs hibernate.In spring the fundatrix, apterous fundatrigeniae and alate fundatrigeniae damage the leaves on the elm and produce pseudogalls.