Pesticides pyrethrum-rotenone

Certainly, in the case of the insecticides, past experience has shown this approach to be successful, with synthetic pyrethroids as the best example. Other commercially useful botanical pesticides include nicotine, pyrethrum, rotenone and several other alkaloids. Similarly, other natural compounds modifying feeding behavior or inhibiting the growth of insect larvae, are considered viable alternatives to acute toxins, for insect control (3). One of the most successful examples so far is Neem, extracted from the seeds of the tree Azadirachta indica. 

Plants have provided several other important pesticides. The group of insecticides called pyrethrums was harvested and refined from chrysanthemums. The plant nux vomica contains strychnine, which was used to kill rodents. Rotenone, another important insecticide was extracted from the root of Denis eliptica. Plant extracts were useful, but difficult to purify and obtain in quantity. Significant increases in the use of pesticides occurred with advances in synthetic chemistry and our understanding of biology. 

Pesticides derived from natural sources include nicotine, rotenone, and pyrethrum. Nicotine is obtained from the dried leaves of Nicotiana tabacum and N rustica. It is rapidly absorbed from mucosal surfaces the free alkaloid, but not the salt, is readily absorbed from the skin. Nicotine reacts with the acetylcholine receptor of the postsynaptic membrane (sympathetic and parasympathetic ganglia, neuromuscular junction), resulting in depolarization of the membrane. Toxic doses cause stimulation rapidly followed by blockade of transmission. These actions are described in Chapter 7. Treatment is directed toward maintenance of vital signs and suppression of convulsions. 

Since 2500 BC, farmers have used pesticides to prevent damage to their crops. The first known pesticide was elemental sulfur, used to dust crops in Sumeria about 4500 years ago. By the fifteenth century, pesticides containing arsenic, mercury, and lead were being applied to crops. In the seventeenth century, nicotine was extracted from tobacco leaves as nicotine sulfate for use as an insecticide. In the nineteenth century, two more natural pesticides were introduced pyrethrum (extracted from chrysanthemums) and rotenone (extracted from the roots and stems of several tropical and subtropical plant species of the genus Lonchocarpus or Derris) [Miller (21A46)]. 

Plant derived pesticides Azadirachtin A and B (obtained from Azadirachta indica), Bacillus thuringiensis, Denis (rotenone), Neem oil (obtained from Azadirachta indica), nicotine, pyrethrum, Spinosad (a mixture of spinosyn A and spinosyn D) derived from soil bacterium Saccharopolyspora spinosa. 

During the 1930s, the need to increase crop yields and boost food production stimulated the development of new, cheap and selective synthetic pesticides as alternatives to naturally occurring materials such as nicotine, rotenone and pyrethrum. In Germany during... 

In reality, pesticides of botanical origin have been used for centuries to protect crops and stored products and to repel pests from human habitations. Among the most well known are pyrethrum, neem, rotenone, nicotine and plant essential oils, although more than 2,000 plant species have been found to possess insecticidal activity [3-4]. However, while most botanical pesticides are known solely for their insecticidal activity, plant essential oils are also known for their uses as fragrances, flavorings, condiments or spices, and many are also considered to have medicinal uses. Given this widespread use, numerous plant essential oils are already widely available and their chemistry is generally well-understood. 

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