Types of Pesticides

There are currently around 600 pesticides, both natural and synthetic. Natural pesticides include both chemicals derived from plant sources and biological agents such as parasitic wasps, mites, bacteria, and chemicals contained within or exuded by plants or bacteria. While there is no inherent reason why natural products should be any safer than synthetic ones (after all, insect venoms and toxins and poisonous plants are natural), it appears that the risks do lie in their potential impact on the environment rather than on their effect in food. There are also increasing numbers of cases where plants have been given a gene which expresses a natural pesticide (see Bacillus thuringiensis, below).

At the time of writing, naturally derived pesticides make up less than 5% of the world pesticide market, but a great deal of work is being devoted to the screening of natural sources and this proportion will certainly increase. The most successful natural product development so far has been that of the pyrethrin insecticides, of which 33 are currently available.

The largest classes of pesticides are pyrethrins, organochlorines, organophosphates, and carba-mates, although there are many smaller classes with only one or two members. The chemical structures of the key members of the major groups are given in Table 1.

New Mothers Guide to Breast Feeding

New Mothers Guide to Breast Feeding

For many years, scientists have been playing out the ingredients that make breast milk the perfect food for babies. They've discovered to day over 200 close compounds to fight infection, help the immune system mature, aid in digestion, and support brain growth - nature made properties that science simply cannot copy. The important long term benefits of breast feeding include reduced risk of asthma, allergies, obesity, and some forms of childhood cancer. The more that scientists continue to learn, the better breast milk looks.

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