Synthetic pesticides selectivities

Selectivities to synthetic pesticides may be explained, in part, by preadaptations to toxic dietary chemicals. Leaf chewing pests, phloem-sucking pests, and entomophagous natural enemies should have very different exposures to dietary toxicants. Plant defensive chemicals are thought to be allocated mostly to specialized organelles or tissues of external structures, and only at low loadings... 

Nicotine is a highly poisonous alkaloid, extracted from special tobacco selected for its high nicotine content. When used as an insecticide, nicotine products are poisonous to most plant pests, including aphids, mealybugs, scales, and spider mites. However, nicotine is also highly toxic to mammals when taken internally or absorbed through the skin— more toxic, in fact, than many synthetic pesticides. It remains toxic on leaf surfaces for several weeks after an application. Also, nicotine products may contain the pathogen that causes tobacco mosaic virus in related... 

During the past decades the excessive use of synthetic pesticides has given raise to several problems including the selection of resistant pest... 

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 Japan, not a few studies to establish local IPM programs using natural enemies have been carried out over the last several years. This is because administrations, as well as consumers, expect to reduce the usage of synthetic pesticides. From the grower s point of view, IPM programs might reduce their work in pesticide applications. Under such circumstances, the selective insecticidal activity of pyridalyl was of interest to researchers and has been incorporated into such studies, mainly since 2002. Spray programs were then introduced and accepted well in some areas. 

Because process mixtures are complex, specialized detectors may substitute for separation efficiency. One specialized detector is the array amperometric detector, which allows selective detection of electrochemically active compounds.23 Electrochemical array detectors are discussed in greater detail in Chapter 5. Many pharmaceutical compounds are chiral, so a detector capable of determining optical purity would be extremely useful in monitoring synthetic reactions. A double-beam circular dichroism detector using a laser as the source was used for the selective detection of chiral cobalt compounds.24 The double-beam, single-source construction reduces the limitations of flicker noise. Chemiluminescence of an ozonized mixture was used as the principle for a sulfur-selective detector used to analyze pesticides, proteins, and blood thiols from rat plasma.25 Chemiluminescence using bis (2,4, 6-trichlorophenyl) oxalate was used for the selective detection of catalytically reduced nitrated polycyclic aromatic hydrocarbons from diesel exhaust.26... 

One approach to the discovery of new insecticides which fulfill the criteria of efficacy, safety, selectivity, etc., is through the study of the natural chemical defenses of plants. Extracts of plants have been used as Insecticides by humans since before the time of the ancient Romans, a practice that continues today with many of the 2000 species of plants known to have insecticidal properties (4-5). The use of insecticidal" plants is especially prevalent among subsistence farmers since plants grown locally are cheaper, and sometimes more accessible, than synthetic chemical pesticides. Commercially, however, only a few of these plants. Including those containing pyrethrins, rotenoids, and alkaloids, have been used to any extent in the United States as sources of insecticides (6-8). 

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