The small brown rice planthopper is an injurious insect on food crop of Ningxia.

灰飞虱是宁夏粮食作物上的一大害虫。

Clanis bilineata tsingtauica is a kind of argricultral injurious insect, distributing in the west and north of china.

豆天蛾是一种大型的农业害虫，在我国西部和北部地区广泛分布。

The prerequisite for the natural enemies to be able to control insect pest is that the increase of injurious insects is restrained by the density of the latter.

捕食天敌能防治病害的前提是害虫猎物数量增长受害虫自身密度的制约。

Entomogenous fungi constitute the largest taxonomic group of insect pathogens. They can usually lead to suppression of injurious insect populations in nature without any help from man.

昆虫病原真菌在自然环境中对害虫数量起着抑制作用，在害虫的微生物防治中也占有独特的地位。

One-way movement of the gut contents prevents accumulation of toxic substances to injurious levels, enabling the insect to favourably tolerate hydrogen cyanide in cassava leaves.

肠溶物的单向流动可以防止有毒物质的积累，使臭腹腺蝗成功耐受木薯叶中的氰化氢。