1、U1 有害生物问题及其防治对策要 点有害生物是什么？有害生物和人类竞争食物或空间、传播病原体、以人为食，或用不同方法威胁人类健康、舒适或安宁。野草可能包括在这个定义内。有害生物最重要特征之一，是它们通常被它们的天敌调节到高的水平。有害生物是经常能逃避它们天敌的物种，可能是由于它们迁入世界新的地区。有害生物 “入侵 ”上海Pests compete with humans for food of shelter, transmit pathogens, feed on humans or otherwise threaten human health, comfort or welfare. W
2、eeds may be included in this definition. One of the most important characteristics of pests is the high degree to which they are normally regulated by their natural possibly due to their importation to new regions of the world. Key NotesWhat is a pest?U1 THE PEST PROBLEM AND CONTROL STRATEGIES有害生物防治
3、目标尽管在有些情况下，有害生物防治的目标是根除有害生物种，然而通常有害生物的防治目的总是降低有害生物种群到一个水平上，在这个水平上进一步降低是无利可图的。这被称为有害生物的经济损害水平（ EIL）， 如果考虑到社会的和环境的舒适利益，或许它被称为美学损害水平（ AIL）。 就疾病而言，根除全部有害生物能够被认为是有理的，这是基于救活一个人远超过任何经济的价值。在实践有害生物的防治中， EIL不像防治活动阈值（ CAT） 那样重要，在经济活动阈值这个有害生物密度上，其作用应该被理解是阻止即将来临的有害生物的爆发。Although in some instances the aim of pest
4、 control is to eradicate the pest species, generally the aim of pest control is to reduce the pest population to a level at which on further reductions are profitable. This is known as the economic injury level (EIL) for the pest, or if social and amenity benefits are included, the aesthetic injury
5、level (AIL). In the case of disease, total eradication can be justified on the basis that the saving of one single life far exceeds any economic costs. In practical pest control ,the EIL is not as important as the control action threshold (CAT) the pest density at which action should be taken in ord
6、er to prevent an impending pest outbreak.The aim of pest control 相关主题 捕食的性质（ J1） 杀虫剂和问题（ U2）捕食行为和猎物反应（ J2） 生物防治和害虫综合治理（ U3）有害生物防治类型限制有害生物损伤粮食作物的方法已被采用数千年，特别是用于栽培防治（例如改变播种日期、或避免在同一地区重复种植相同的作物）。生物防治（利用天敌 捕食者与寄生物）也具有悠久的历史。本世纪以来，化学防治变成主要的途径，尽管存在着严重的毒性和其他一些问题。抗有害生物的作物品种的培育是另一类有价值的对策。Approaches to limit p
7、est damage to food crops have been adopted for thousands of years, particularly using cultural control (e.g.altering the sowing date or avoiding repeatedly replanting the same crop in the same place). Biological control (the use of natural enemies predators and parasites) has also had a long history
8、. This century, chemical control became a key approach, although there are serious toxicity and other problems. The development of pest resistant crop varieties is another valuable strategy.Types of pest controlRelated topics The nature of predation (J1) Pesticides and problems (U2) Predator behavio
9、r and prey Biological control and integrated response (J2) pest management (U3)U2 杀虫剂和问题要 点化学杀虫剂和除莠剂无机化合物是除莠剂的惯用试剂，但由于具有持久性和非特异性的问题，如像硼酸盐和含砷制剂的化合物是极少应用的。化学杀虫剂一般用于处理特殊地点上的特殊害虫。可是问题出现了，因为这些化合物对其他动物是有毒的，并且很多化学物持续存在于环境中。Inorganic compounds were traditional herbicides, but due to problems with persistenc
10、e and nonspecificity, compounds such as borates and arsenicals are rarely used. Chemical pesticides are generally used to treat a particular insect pest at a particular location. However, problems arise because these chemicals are toxic to other animals, and because many chemicals persist in the environment.Key NotesChemical insecticides and herbicidesU2 PESTICIDES AND PROBLEMS
