tailieunhanh - Pesticide profiles : Toxicity, environmental impact and fate - Chapter 2

Pyrethroids và thực vật khác Lớp cái nhìn tổng quan và bối cảnh mô tả chung Pyrethroids và thuốc trừ sâu thực vật khác được nhóm lại với nhau không phải bởi vì họ có đặc tính tương tự như độc tính như organophosphates hoặc carbamate, nhưng vì tất cả họ đều có nguồn gốc sinh học. Thuốc trừ sâu có thể được chiết xuất từ tự nhiên vật liệu, hoặc họ có thể được tổng hợp trong phòng thí nghiệm thương mại. Các vật liệu tự nhiên phổ biến nhất đến từ các nhà máy. Một số nhà máy đã. | Section II Pesticide profiles 2000 CRC Press LLC chapter two Pyrethroids and other botanicals Class overview and general description Background Pyrethroids and other botanical pesticides are grouped together not because they have similar toxicological properties like the organophosphates or carbamates but because they all have biological origins. Pesticides may be extracted from naturally occurring materials or they can be synthesized in commercial laboratories. The most common natural materials come from plants. Some plants have developed over long periods of time substances that deter plant-eating insects. The plants use these compounds as protection from insects. Researchers have isolated a number of compounds from plants that are effective insecticides or fungicides. Development of these botanical pesticides is one of the fastest growing areas in the pesticide industry. The World Health Organization in 1967 stated that all of the most poisonous materials so far known are in fact of natural origin 1 . Whether this is still true or not is unimportant however the comment points out that just because something is found in nature does not mean that it is harmless 1 . Pesticides extracted from plants or synthesized to mimic compounds found in plants are powerful and effective control agents. Plant-derived pesticides fall into several different broad classifications. By far the largest group of such pesticides consists of pyrethrum and its related synthetic compounds pyrethroids. Pyrethrum comes from chrysanthemums. There are currently over 20 pyrethroids and they constitute the single largest group of natural insect chemical control agents in the world 2 . Another class of botanicals is the rotenoids. They are found in several plants in the bean family. Rotenone is one of six compounds in this group. It is used as a fish poison. A third important category of botanicals the nicotinoids comes from tobacco and several other plants. Nicotine is the most commonly used