Developing Countries

Bloand botanical pesticides are often grouped together in developing countries as possible alternatives to chemical pesticides. In reality, botanic pesticides are no different from chemical pesticides, but blopestlcides are all far removed from them. Botanical pesticides derived from tobacco ( Nicotiana tabacum ), pyrethrum ( Chrysanthemum cznerariaefolium ), derrls roots, neem, and so on, have been known for many decades, but occupy only a very small fraction of the overall pesticide market, which is now worth almost $28 billion, and is likely to grow to $34 billion by the year 1998. Some of the well-known botanical pesticides will fail today’s strict and exhaustive reglstratlon requirements. However, the botanical pesticides gave ideal models for sclentlsts to modify structure and optimize biological activity The synthetic pyrethroids revolutionized the pesticide industry in the 1970s, and today share more than a $2 billion market. In the 1980s and 1990s, based on mcotine and strobilurin, major inventions were made in bringing to the market compounds, such as Bayer’s (Germany) imidacloprid ( 1 ) and ICI (UK) A5504 (azoxystrobm) ( 2 ), shown in Fig. 1 . In addition, BASF also has invented a strobilurin analog called kresoxlme methyl (BAS490F). These will have a big impact in the plant fungicide market. In these mventlons, traditional structure-activity relationship, partition coefficients, mode-of-action studies, and computer graphics have been utilized by synthetic chemists to invent key molecules that could fit the relevant enzyme surface, like lock and key, to invoke the needed biological activity and at the same time not interfere with mammalian and aquatic species and not accumulate in the environment.

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