探明造成作物损失的原因,是建立确保子孙后代吃穿战略思想的基础。象昆虫、杂草、植物的病害、线虫、啮齿类动物及某些鸟类等有害生物,是生物因素引起绝大部份作物损失的重要原因。这些有害生物在作物产前为害一般可使作物的潜在产量损失30％以上。在美国,有害生物至少包括160种细菌、250种病毒、800种真菌、2000种杂草以 Identifying the causes of crop losses is the basis for establishing the strategic thinking that will ensure that future generations will eat and wear. Pests such as insects, weeds, plant diseases, nematodes, rodents and certain birds are important causes of most crop losses due to biological factors. Harmfulness of these pests in prenatal crops can generally result in the loss of more than 30% of the potential crop yield. In the United States, pests include at least 160 bacteria, 250 viruses, 800 fungi and 2000 weeds