Mechanical, physical and biological control measures

Abstract

Modern synthetic insecticides have achieved excellent results in many spheres; in particular, they have revolutionized the control of insect-borne diseases, especially in the tropics. These successes are not unqualified, however, as their regular use frequently leads to the emergence of resistant strains of the pests. Furthermore, the extensive use of chemical poisons has been denigrated on account of their possible danger to man and animals. For these reasons, it may be desirable to review certain alternative measures, which may seem rather old-fashioned. It is worth remembering that certain insect-borne diseases which were formerly endemic in England were not eliminated by the skill or knowledge of doctors or entomologists, but died out as a result of the changing habits of the citizens. Thus, malaria receded as agricultural practices changed and improved; typhus died out when body lice became exceedingly rare; plague has long been extinct since better housing prevented close contact with the black rat and its fleas.