Sâu bệnh, theo nghĩa rộng, là bất kỳ sinh vật - thực vật, động vật, hoặc vi sinh vật đó là phá hoại hay phiền hà, hoặc sống mà nó là không mong muốn. Thuốc trừ sâu tham khảo cho bất kỳ hóa chất dự định để phòng ngừa, ngăn chặn, phá hủy, hoặc nếu không làm suy yếu khả năng của các dịch hại đối với cạnh tranh với các sinh vật mong muốn, chẳng hạn như các loại cây trồng, động vật, hoặc con người. Thuốc trừ sâu có thể được phân loại theo nhiều cách khác nhau, chẳng hạn như mục. | Chapter 13 Pesticides and Related Materials INTRODUCTION A pest broadly defined is any organism - plant animal or microorganism -that is destructive or troublesome or living where it is unwanted. Pesticides refer to any chemicals intended to prevent deter destroy or otherwise impair the ability of pests to compete with desired organisms such as crops animals or humans. Pesticides can be classified in different ways such as by their target chemical nature physical state and mode of action. Classification based on the target is perhaps the most widely known insecticides herbicides fungicides and rodenticides Table .This chapter considers the chemistry characteristics and health effects of several representative groups of pesticides and herbicides. It then discusses several halogenated hydrocarbons that have become of much concern in recent years including polychlorinated biphenyls PCBs and dioxins. INSECTICIDES Introduction Insecticides are those compounds that are effective against insects. Many insecticides have been developed and used to control various species of insects. While most insecticides are applied as sprays others are applied as dusts aerosols fumigants and baits. The majority of insecticides used today are synthetic organic chemicals and most of them are nerve poisons. They act by inhibiting the organism s enzymes or interacting with other target sites vital to Table Classification of Pesticides Method of classification Example By target Insecticides herbicides fungicides rodenticides algaecides nematocides By chemical nature Natural organic compounds inorganic compounds chlorinated hydrocarbons organophosphates carbamates By physical state By mode of action Dusts dissolved solutions suspended solutions volatile solids Contact poisons fumigants stomach poisons 2005 by CRC Press LLC the proper functioning of the insect s nervous system. Other insecticides act by blocking essential processes such as respiration. Although there
