Pest control insecticides

This comprehensive definition makes it elear that a wide number of substances may be eonsidered to be pestieides, and that the eommonality among all pestieides is their ability to provide eontrol over pests. A variety of classifications for pesticides have been developed that are specific for the type of pest controlled. Insecticides, for example, are pesticides that control insects, while herbicides control weeds and fungicides control plant diseases (molds). In addition to these major classifications of pesticides, there are many other classifications. These include nematicides (for nematode control), acaracides (mite control), rodenticides (rodent control), molluscicide (snail and slug control), algacides (algal control), bacteriocides (bacterial control), and defoliants (leaf control). 

Since the early 1940s, insecticides have been of immeasurable value in curbing the ravages of insect pests. In the words of the National Academy of Sciences "...when their use is approached from sound ecological principles, chemical pesticides provide dependable and valuable tools for the biologist. Their use is indispensable in modem society. There are many problems of insect pest control for which the use of chemicals provides the only acceptable solution. Chemical pesticides will continue to be one of the most dependable weapons for the entomologist for the foreseeable future" (6). 

The development of malathion in 1950 was an important milestone in the emergence of selective insecticides. Malathion is from one-half to one-twentieth as toxic to insects as parathion but is only about one two-hundredths as toxic to mammals. Its worldwide usage in quantities of thousands of metric tons in the home, garden, field, orchard, woodland, on animals, and in pubHc health programs has demonstrated substantial safety coupled with pest control effectiveness. The biochemical basis for the selectivity of malathion is its rapid detoxication in the mammalian Hver, but not in the insect, through the attack of carboxyesterase enzymes on the aUphatic ester moieties of the molecule. 

The proper choice and appHcation of an insecticide for pest control are predicated upon factors, eg, the life history and ecology of the pest, the relation of pest population to economic damage, the effect of the insecticide on the pest or its plant or animal host, related organisms in the ecosystem, and proper timing of the appHcation to prevent illegal residues at harvest and to avoid damaging of bees and other pollinating insects. 

Pests and Insecticides. The most destmctive pests of the cotton plant are the boU weevil and the boUworm/budworm complex. They are serious threats to the cotton industry in countries around the world. The boU weevil migrated from Mexico around 1892 and spread over the entire cotton belt within 30 years. The domestic cotton crop lost to the weevil is worth 200 million a year. In addition, about 75 million a year is spent for pesticides to control this destmctive pest (8). Unfortunately, some insecticides used to control the weevil kill many beneficial insects. Among the undesired casualties are insects that help to control the boUworm and the tobacco budworm, pests that cause another 200 million loss in cotton. 

Scbadlings-bekai pfttilg i /. pest control, -be-kkmpftmgsmitt, n. pcst-controUing agent, pesticide, insecticide, etc. 

Basically growth hormones alter the normal growth of some insect species. The juvenile growth hormone worked effectively to kill some insects in the laboratory, but when applied in the field for pest control, the hormone was not effective. Its problems centered on its high cost, rapid rate of breakdown after application, and its broad spectrum effects. For example, the hormone was found to kill beneficial species as well as pest species, much like insecticides. Thus far, it has not proven to be a useful technology for pest control (42). 

The environmental fate and behavior of compounds depends on their physical, chemical, and biochemical properties. Individual OPs differ considerably from one another in their properties and, consequently, in their environmental behavior and the way they are used as pesticides. Pesticide chemists and formulators have been able to exploit the properties of individual OPs in order to achieve more effective and more environment-friendly pest control, for example, in the development of compounds like chlorfenviphos, which has enough stability and a sufficiently low vapor pressure to be effective as an insecticidal seed dressing, but, like other OPs, is readily biodegradable thus, it was introduced as a more environment-friendly alternative to persistent OCs as a seed dressing. 

Apart from the importance of OP resistance in pest control, ecotoxicologists have become interested in the development of resistance as an indication of the environmental impact of insecticides. Thus, the development of esteratic resistance mechanisms by aquatic invertebrates may provide a measure of the enviromnental impact of OPs in freshwater (Parker and Callaghan 1997). 

The Federal Insecticide, Fungicide, and Rodenticide Act affords added protection against the dangers inherent in the use of newer means of pest control. The manufacturer has greater responsibility for furnishing specific information as to how the product can be used effectively but without damage to the user, crops or animals, or the public. 

California, one of the first states to recognize the need for control, enacted legislation in 1901 governing the sale of insecticides. This was later broadened to include, under the term economic poisons, all materials used for pest control. In the almost 50 years of regulating these materials in California the law, which is the Economic Poisons Article of the Agricultural Code, has been modified from time to time, but the basic purpose has been to prevent sale of worthless products, to provide for adequate labeling, and to assure users that the products correspond to guarantee. 

Each insecticide, fungicide, rodenticide, herbicide, or other pest control product must be registered with the State Bureau of Chemistry as an economic poison before being offered for sale in California. Registration may be refused, after hearing, for a product that is of little or no value for the purpose intended, or that is detrimental to vegetation (except weeds), to domestic animals, or to the public health and safety, when properly used. 

The use of plant extracts for insect control dates into antiquity the use of Paris green as an insecticide for control of the Colorado potato beetle in 1867 probably marks the beginning of the modern era of chemical control of injurious insects. The development of lead arsenate followed later in the nineteenth century for gypsy moth control. The commercial production of nicotine insecticides, the production of calcium arsenate at the time of the first world war, and the use of fluorine, arsenical, and cyanide compounds, as well as other inorganic chemicals for insect control, were important steps in pest control. These chemicals were applied largely by dilute high pressure sprays or dusts. 

Andreas Buxtorf and Max Spindler. Fifteen Years of Geigy Pest Control. Basel, Switzerland J. R. Geigy S.A., 1954. Source for Geigy woolen specialty natural insecticides delousing during World War I pre-DDT insecticides pyrethrum and rotenone as controls and visit to United States. 

Trialkyltin and triaryltin compounds possess powerful biocidal properties. These are manifested to a high degree only when the tin atom is combined directly with three carbon atoms, as in trialkyl compounds (R3SnX) biocidal effects are at a maximum when the total number of carbon atoms attached to Sn is 12. These compounds are used as fungicides, insecticides and as pest control in agricultural applications29. 

Nonpoint source sampling occurs where the analyte of interest is dispersed over a large area such that a specific point of origin cannot be ascertained. The innate occurrence of analytes of interest would be an example of a nonpoint source. The occurrence of plant nutrients, either naturally occurring or from fertilization, is an example of a nonpoint source of agricultural analytes. Herbicides, insecticides, and pest-control agents are, once applied on a field scale, also potential nonpoint sources of analytes. It is common to think of crop... 

The insecticides and miticides mentioned are not the only ones known to be effective against cotton pests, but they include most of those used for that purpose in the United States. Many of them are imported in considerable quantities into Latin American countries and have proved their effectiveness there. Approximately 44,000,000 pounds of technical organic insecticides (DDT, BHC, toxaphene, aldrin, dieldrin, parathion, etc.), 3,600,000 pounds of calcium arsenate, and 82,000 pounds of nicotine sulfate were exported from the United States to these countries during 1953. Some insecticides are exported from Europe, particularly Folidol (methyl parathion) from Germany. Even though these imports represent considerable quantities of insecticides, they are still far short of the minimum needs for adequate cotton-pest control. 

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