Insects have more species ( over million already described ) than any other for of animal life and are in many ways to most indestructible form. About 1 percent of the species offer hazard to humans ans animals , but this means that the US harbour 600 troublesome species. Humans and pests fight a continuous battle for food and shelter; insects alone claim about 10 percent of crops in the US , and about 14 percent worldwide. Various misery-causing diseases are carried by insects : malaria yellow fever, typhus, and plague to name a few . For us to survive at current population levels , pesticides must be used and new ones constantly developed. When insecticides are applied widely , all about few of the local insects are destroyed, but the remaining ones are those most resistant to the destroying agents. After several generations , this selection makes the surviving insects increasingly resistant to the destroying agent. Eventually complete resistant may occur Safety Regulations Chemis...