首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Pest Control P1: Pest control is at least as old as agriculture, as there has always been a need to keep crops free from pests.
Pest Control P1: Pest control is at least as old as agriculture, as there has always been a need to keep crops free from pests.
admin
2018-10-18
36
问题
Pest Control
P1: Pest control is at least as old as agriculture, as there has always been a need to keep crops free from pests. Many pest species that are native to North America, such as white-footed mice and ground moles, are more nuisance pests and are usually regulated by native predators and parasites. This situation is not true for non-indigenous pests in North America, such as brown rats and cockroaches. It is evident that measures must be undertaken to eradicate these pests. One of the most popular methods of pest control is using chemical pesticides, which can be dated back 4,500 years, when the Sumerians used sulfur compounds as insecticides. However, chemical control has its downsides. For one thing, chemical pesticides have many unintended consequences through their effects not just on the target species, but on a wide array of non-target species as well, often eliminating them and thereby upsetting the existing food webs, especially through the suppression of native predator species. For another, living organisms evolve and increase their resistance to chemical pesticides unless the target population is completely exterminated or is rendered incapable of reproduction.
P2: Importation or classical biological control involves the introduction of a pest’s natural enemies to a new locale where they do not occur naturally. Farmers long ago observed that enemies of pests act as controls. As early as 300 C.E., the Chinese were introducing predatory ants into their citrus orchards to control leaf-eating caterpillars. Early instances of such pest control methods were often unofficial and not based on research, and some introduced species became serious pests themselves. When they adapt to the new environment and leave their enemies behind, these species can quickly get out of control and become a real problem for local populations. Because serious pests are often non-native species, biological control involves the introduction of a non-indigenous predator or parasite to control the pest. For instance, the introduction of the cactus-eating moth, a native of Argentina, into Australia effectively reduced and controlled the rapidly spreading prickly pear, which had been introduced into Australia in 1901.
P3: But biological control, like chemical control, can backfire. The success of the cactus-feeding moth in controlling prickly pear numbers in Australia encouraged its introduction to several West Indies islands to control prickly pear there. In time, the moth made its way to Florida, where it now threatens the existence of several native prickly pear species. The moral is that sometimes when a non-native bioagent is introduced to control a non-native pest species, it, in turn, becomes a threat that must be assessed before it can be released.
P4: To make up for the drawbacks of both chemical and biological control methods, entomologists have invented a broad-based approach that integrates practices for economic control of pests, which is known as "Integrated Pest Management" (IPM). IPM involves the careful consideration of all available pest control techniques and subsequent integration of appropriate measures that discourage the development of pest populations and keep pesticides and other interventions to levels that are economically justified and reduce or minimize risks to human health and the environment. The objective of IPM is to control the pest not at the time of a major outbreak, but at an earlier time, when the size of the population is easier to control. The approach is to rely first on natural mortality caused by weather and natural enemies, with as little disruption of the natural system as possible, and to use other methods only if they are needed to hold the pest below the economic injury level.
P5: IPM emphasizes the growth of a healthy crop with the least possible disruption to agro-ecosystems and encourages natural pest control mechanisms. Entomologists and ecologists have urged the adoption of IPM pest control since the 1970s IPM allows for safer pest control. This includes considerable field work managing insects, plant pathogens, and weeds, and the intensity of control or no control is based on the degree of pest damage that can be tolerated, the costs of control, and the benefits to be derived.
P1: Pest control is at least as old as agriculture, as there has always been a need to keep crops free from pests. Many pest species that are native to North America, such as white-footed mice and ground moles, are more nuisance pests and are usually regulated by native predators and parasites. This situation is not true for non-indigenous pests in North America, such as brown rats and cockroaches. It is evident that measures must be undertaken to eradicate these pests.
■ One of the most popular methods of pest control is using chemical pesticides, which date back 4,500 years, when the Sumerians used sulfur compounds as insecticides. However, chemical control has its downsides.
■ For one thing, chemical pesticides have many unintended consequences through their effects not just on the target species, but on a wide array of non-target species as well, often eliminating them and thereby upsetting the existing food webs, especially through the suppression of native predator species. ■ For another, living organisms evolve and increase their resistance to chemical pesticides unless the target population is completely exterminated or is rendered incapable of reproduction. ■
According to paragraph 5, each of the following helps to determine how intensely to apply pest control measures EXCEPT
选项
A、how much pest damage can be tolerated
B、the cost of pest control measures
C、what can be gained through pest control measures
D、whether pest control measures have been used before
答案
D
解析
【否定事实信息题】末句最后提到控制的强度或零控制是基于害虫的损害程度可否容忍、控制的成本和能得到的好处。D选项未提及。
转载请注明原文地址:https://jikaoti.com/ti/YchYFFFM
0
托福(TOEFL)
相关试题推荐
ChooseTWOletters,A-E.WhichTWOsubjectsdidMartinalikebestbeforegoingtouniversity?AArtBHistoryCFrenchDEnglish
AsystemwasdevelopedtocontroltrafficcongestionontheM25motorway.Expertsuse【L5】________informationfromthemotorw
AsystemwasdevelopedtocontroltrafficcongestionontheM25motorway.Expertsuse【L5】________informationfromthemotorw
LaughterThenatureoflaughterlaughterisa【L31】________process—involvesmovementandsounditiscontrolledbyour【
In1974thespaceprobeMariner10discovered______Mercury’ssurfaceiscrateredbymeteoriteimpacts.
Whatdoesthepassagemainlydiscuss?Theword"rudimentary"inline21isclosestinmeaningto
(When)precipitationoccurs,(some)ofitevaporates,somerunsoff(the)surfaceitstrikes,andsome(sinking)intotheground
Theterm"iceage"referstoanyofseveralperiodsoftimewhenglacierscoveredconsiderablymoreofEarth’ssurface______
随机试题
某公司经销家用清洗机,年销售量6000台,采购单价800元/台,订购成本300元/次,每台清洗机的年持有成本为10元。若供应商要求的订购提前期为10天,年工作时间以250日计算,不设安全库存量。最大库存量为()台。
患者,女,70岁。心绞痛发作持续3小时,含硝酸甘油无效来院急诊。心电图示Ⅱ、Ⅲ、aVF导联ST段呈弓背向上型抬高6mm,V1~V3导联ST段水平型压低4mm,偶发室性期前收缩1次,拟诊急性心肌梗死入院。(假设信息)如果出现急性乳头肌功能不全,心脏检查可
根管机械预备的目的如下,除外
______是指通过采用技术和管理手段使事故不发生。______是通过采取技术和管理手段使事故发生后不造成严重后果或使后果尽可能减少。
会计核算软件应具备初始化功能,其中应进行初始化的内容包括()。
下列关于错觉的说法不正确的是()
我们通过守正创新形成了中国特色社会主义理论体系,守正就不能偏离马克思主义、社会主义,但不是________,还要往前发展、与时俱进,否则就是僵化的、陈旧的、过时的。
在日常生活中,价格变动对需求量影响较小的一组商品是()。
RIPv2对RIPvl协议的改进之一是采用水平分割法,以下关于水平分割法的说法中,错误的是()。
IsCollegeReallyWorththeMoney?TheRealWorldEsteGriffithhaditallfiguredout.WhenshegraduatedfromtheUn
最新回复
(
0
)