Pest controls

Time of sowing can be very important for reducing pest problerrrs. Cereal growers in high-risk areas normally drill winter cereals after the rrtiddle of October to reduce aphid attack arrd trarrsfer of barley yellow dwarf virus (BYDV). MairKrop carrots are sown at the end of May or in early Jrme to avoid the first generation of carrot fly. 

On a Umited scale, crop covers are used over susceptible crops when there is likely to be damage. These crop covers form veiy effective barriers against pests such as carrot and cabbage root fly and caterpillars. Other than cost the problem with crop covers is that they have to be removed before weeding can be carried out. 

Pheromone traps are sometimes used as an aid to warn of possible pest problems. There are also a limited number of permitted treatments including soap sprays a inst aphids and the bacteria treatment, Bacillus thuringiensis for control of caterpillars such as the cabbage white. There are several other permitted, naturally occurring, biological control agents mainly for use in glasshouses. 

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Grandisol, with a four-membered ring, is another insect hormone, the male sex hormone of the boll weevil to be precise. It may also be useful as a highly specific pest control. How might it be made ... 

Every continent, except Antarctica, grows com 40% of the present world crop is produced in the United States. In the 1987—1988 crop year, 12 states (Iowa, HI., Nebr., Minn., Ind., Ohio, Wis., Mo., S. Dak., Mich., Kans., and Tex. in order of production) produced 157.5 million metric tons (6.2 biUion bushels) that was 88% of the United States and 36% of the world s crop (66). Yield is influenced by many factors, including climate, pest control, planting density, and fertilization. Yield in the United States has increased from about 1.5 metric tons /hectare in the 1930s to about 7.5 metric tons /hectare. In 1985, a test plot produced 23.2 metric tons /hectare and yields approaching 40 metric tons /hectare are considered possible com is the most productive of the principal food crops. 

Most emphasis is placed on a program of rigorous preventive maintenance. Appropriate climate conditions can help to prevent mold attack, which typically only occurs at elevated relative humidity. Storage furniture which provides an effective barrier for insects, regular inspection of the collections, monitoring of all collection areas with insect traps, and access control measures which minimize the chance of insect entry into the collection areas, are some aspects of an effective pest control management program (175). 

L. A. Zycherman and J. R. Richard, M Guide to Museum Pest Control, Poundation of the American Institute for Conservation of Historic and Artistic Works and the Association of Systematic CoUections, Washington, D.C., 1988. 

Fluoroacetic acid [144-49-OJ, FCH2COOH, is noted for its high, toxicity to animals, including humans. It is sold in the form of its sodium salt as a rodenticide and general mammalian pest control agent. The acid has mp, 33°C bp, 165°C heat of combustion, —715.8 kJ/mol( —171.08 kcal/mol) (1) enthalpy of vaporization, 83.89 kJ /mol (20.05 kcal/mol) (2). Some thermodynamic and transport properties of its aqueous solutions have been pubHshed (3), as has the molecular stmcture of the acid as deterrnined by microwave spectroscopy (4). Although first prepared in 1896 (5), its unusual toxicity was not pubhshed until 50 years later (6). The acid is the toxic constituent of a South African plant Dichapetalum i mosum better known as gifirlaar (7). At least 24 other poisonous plant species are known to contain it (8). 

P. A. Hedin, Use ofiNaturalProducts in Pest Control, developing Research Trends, ACS Symposium Series 449, American Chemical Society, Washington, D.C., 1991, pp. 1-11. 

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 primary goals of 1PM are (/) to determine how the life system of the pest needs to be modified to reduce the numbers to tolerable levels, ie, below the economic threshold (2) to apply biological knowledge and current technology to achieve the desired modification, ie, appHed ecology and (2) to devise procedures for pest control compatible with economic and environmental control aspects, ie, economic and social acceptance (9). 

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. 

C. B. Huffaker, ed., Neiv Technology of Pest Control, John Wiley Sons, Inc., New York, 1980. 

D. A. Nordlund, R. L. Jones, and W. J. Lewis, eds., Semiochemicals Their Role in Pest Control, Wiley-lnterscience, New York, 1981. 

NPCA Tech. Release No. 15-69, National Pest Control Association, Vienna, Va., 1969. 

J. E. Besser, Proceedings of the 7th Vertebrate Pest Control Conference, Monterey, Calif., 1976, p. 11. 

Many factors affect the mechanisms and kinetics of sorption and transport processes. For instance, differences in the chemical stmcture and properties, ie, ionizahility, solubiUty in water, vapor pressure, and polarity, between pesticides affect their behavior in the environment through effects on sorption and transport processes. Differences in soil properties, ie, pH and percentage of organic carbon and clay contents, and soil conditions, ie, moisture content and landscape position climatic conditions, ie, temperature, precipitation, and radiation and cultural practices, ie, crop and tillage, can all modify the behavior of the pesticide in soils. Persistence of a pesticide in soil is a consequence of a complex interaction of processes. Because the persistence of a pesticide can govern its availabiUty and efficacy for pest control, as weU as its potential for adverse environmental impacts, knowledge of the basic processes is necessary if the benefits of the pesticide ate to be maximized. 

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