Atrazine usage

Similarly to usage patterns in the USA, 75% of the pesticides used in Ontario in 1998 were herbicides [26]. Furthermore, herbicides applied on field corn and soybeans accounted for 65% of the total pesticide used in 1998 in Ontario. Metolachlor, glyphosate, atrazine, dicamba, and bentazon were the major herbicides used in Ontario agriculture in 1998. These five herbicides accounted for 76% of the total herbicide usage in Ontario. Atrazine usage on... 

Taking all findings together, atrazine resistant biotypes obviously have a high positive selection value under conditions of continous atrazine usage in agricultural areas. But in the absence of atrazine and other triazines their (mostly) reduced photosynthetic capacity diminishes their superiority. 

Khan, S.U. and W.J. Saidak. 1981. Residues of atrazine and its metabolites after prolonged usage. Weed Res. 21 9-12. 

In comparison with OC pesticides, the current-use OP and carbamate pesticides are relatively more water soluble and less bioaccumulative. However, because of the high volume of their usage, there is a potential for these compounds to be present in the environment. Herbicides such as atrazine, metolachlor, and alachlor have been surveyed in the Great Lakes [59] and along the margins of fields, streams, and tributaries within the Great Lakes Basin [5,60]. 

Table 5.3 Usage of atrazine in forage com in the United Kingdom from 1974 to 1997 (Thomas, 2001)...

Soil persistence of triazines is important in forest usages. Much literature confirms that significant gains are made by reducing herbaceous plant cover for more than 1 year following planting. The triazines (e.g., simazine, atrazine,... 

The triazines are very widely used herbicides. The best known and the most widely used of these compounds is atrazine. This compound ranks second in terms of usage in the United States (just behind glyphosate) 35-40 million kilograms of atrazine was used in 2001. This compound has been manufactured by Ciba-Geigy since... 

Figure 1.2 Usage of selected pesticides in the United Kingdom between 1983 and 1997. The data are expressed as kilogrammes of active substance applied. The compounds included are carbaryl, dicofol, quinalphos, parathion, gamma-HCH, DDT, methoxy-chlor, amitrole, metribuzin, atrazine, linuron, diuron, 2,4,5-T, 2,4-D, nitrofen, trifluralin, fenarimol, sodium 2-phenylphenoxide, vinclozolin, ziram, zineb-ethylenethiuram disulfide zineb, thiram, maneb and mancozeb. Each has been alleged to exhibit some endocrine-disrupting properties...

A close examination of this usage table shows that the herbicide atrazine has held the number one spot for the last 20 years. This compound is often used in nonfood crops such as cotton. However, some compounds are notably absent from the 1993 tabulation, including toxaphene, methyl-parathion, car-baryl, propachlor, DSMA, linuron, aldrin, carbofuran, chloramben, maneb, sodium chlorate, propanil, DBCP, malathion, dinoseb, and chlordane. It should also be noted that DDT, the pesticide on which Silent Spring was focused and which continues to be used as the example of man s folly with chemicals, is not on either list. The one generalization that can be made concerning this fist of deletions is that most of these pesticides are more persistent than the compounds that replaced them and a significant number of them are chlorinated hydrocarbons. It is important to keep these compounds in mind since popular press accounts of pesticide contamination often quote incidences of exposure to unnamed pesticides and then focus most discussion... 

The triazines make up the final general class of herbicides. This class includes the most prevalent pesticide in use for over two decades, atrazine. It also includes prometon, propazine, and simazine. Acute poisoning with the triazines results in anorexia, depression, and muscular symptomology. The oral doses in rodents required for toxic effects are greater than 1.74 gAg, again making these compounds extremely safe. There is no evidence of toxicity from field usage reports. 

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