Copper disease control

In the European Union (EU) replacement of copper-based fungicides with other methods of disease control is a priority in organic farming policy (Anonymous, 2002). They were due to be prohibited by law for use in organic farming in the EU from March 2002 but the ban was delayed because of the increased risk of crop diseases and associated economic losses for organic producers in the medium to long term, until effective alternative... 

Toxic effects have not stopped copper spraying, because toxicities have been far outweighed by good results from disease control. However, toxic effects need more serious study. They may be more noticeable in warm moist coffee regions than in the dried cooler parts. 

The advances in disease control made in Europe and the associated increases in crop yields prompted further research in the US. Whilst the ensuing collaborative efforts of the French and American pathologists undoubtedly impacted upon the development of, in particular, copper and sulfur fungicides, such opportunities for travel between continents are never missed by Nature and it is likely that the appearance in France at that time of Guignardia bidwellii, another pathogen of vines native to the New World, was no coincidence. 

Most fungicides developed for plant disease control before 1965 are multisite biochemical inhibitors that lack the chemical properties and biological specificity required for internal therapeutic action in higher plants. This group of plant protectants include such compounds as the Inorganic copper fungicides, captan, chlorothalonil, dithiocarbamates and chlorinated quinones. 

The effectiveness of modern masks depends on both physical adsorption and chemical inactivation of the threat agent. For example, in the M17 protective mask the adsorbent, known as ASC Whetlerite charcoal, is charcoal impregnated with copper oxide and salts of silver and chromium.6 The M40 protective mask uses an ASZ impregnated charcoal, which substitutes zinc for the hexavalent chromium (CrVI). The Centers for Disease Control and Prevention and the National Institute for Occupation... 

H.T. Michels, S. A. Wilks, J.O. Noyce, C.W. KeevU. Copper alloys for human infectious disease control. In the Proceedings of the Materials Science and Technology Conference, Copper for the 21st Century Symposium, Pittsburgh, PA,September 25-28, 2005. 

Herbicides. An array of herbicides are registered for use in aquatic sites, but copper sulfate and diquat dibromide are of additional interest because they also have therapeutic properties (9,10). Copper sulfate has been used to control bacteria, fungi, and certain parasites, including Jchthjophthirius (ich). Diquat dibromide can control columnaris disease, but it also exhibits fungicidal properties (9,10). EPA recentiy proposed to limit the amount of diquat dibromide, endothaH, glyphosate, and simazine that can be present in drinking water therefore, the use of these compounds may be reduced if they cannot be removed from the effluent. 

Copper has been employed as a bactericide, moUuscicide, and fungicide for a long time and is of importance in the control of schistosomiasis (see also Antiparasitic AGENTS, ANTHELMINTICS FUNGICIDES, AGRICULTURAL). Addition of copper to lake water acts as an efficient deterrent to transmittal of the disease by eliminating snails that act as hosts for the responsible parasite. Copper is commonly utilized at ca 0.1 mg/L as an algicide. In fresh water, acute toxicosis in fish is unusual if the copper concentration is below 0.025 mg/L (70) (see Poisons, economic). 

Copper compounds are used routinely and widely to control freshwater snails that serve as intermediate vectors of schistosomiasis and other diseases that afflict humans (Hasler 1949 NAS 1977 Rowe and Prince 1983 Winger etal. 1984 Al-Sabri etal. 1993). These compounds include copper sulfate, copper pentachlorophenate, copper carbonate, copper-tartaric acid, Paris green (copper arsenite-acetate), copper oxide, copper chloride, copper acetyl acetonate, copper dimethyl dithiocar-bamate, copper ricinoleate, and copper rosinate (Cheng 1979). Also, many species of oyster enemies are controlled by copper sulfate dips. All tested species of marine gastropods, tunicates, echinoderms, and crabs that had been dipped for 5 seconds in a saturated solution of copper sulfate died if held in air for as little as a few seconds to 8 h mussels, however, were resistant (MacKenzie 1961). 

Copper discharges to the global biosphere are due primarily to human activities, especially mining, smelting, and refining copper and the treatment and recycling of municipal and industrial wastes. Some copper compounds, especially copper sulfate, also contribute to environmental copper burdens because they are widely and intensively used in confined geographic areas to control nuisance species of aquatic plants and invertebrates, diseases of terrestrial crop plants, and ectoparasites of fish and livestock. 

Humans given zinc supplements should be aware of possible complications (Fosmire 1990). Low intakes of 100 to 300 mg of zinc daily in excess of the recommended dietary allowance of 15 mg Zn daily may produce induced copper deficiency, impaired immune function, and disrupted blood lipid profiles. Patients treated with zinc supplements (150 mg daily) to control sickle cell anemia and nonresponsive celiac disease developed a severe copper deficiency in 13 to 23 months normal copper status was restored by cessation of zinc supplements and increased dietary copper (Fosmire 1990). 

This fungicide, as well as certain other organics, does not cause the tacky condition of latex said to be induced by copper contaminations. In Brazil and Costa Rica, rubber planters use much Dithane for nursery spraying. There are still some who prefer a certain amount of copper spray, but in Costa Rica, at least, the organic material is much more acceptable. It is also used for leaf disease on old trees in tap, being held for some special reason. Probably 10 tons of Dithane are used in the Western Hemisphere annually for control of South American leaf disease, and somewhat less than half as much of so-called insoluble copper sprays are still being applied. 

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