Herbicidal use

Herbicide Glasses and Databases. Herbicides can be classified as selective and nonselective. Selective herbicides, like 2,4-D (2,4-dichlorophenoxyacetic acid), metolachlor [51218-45-2] and EPTC [759-94 ] are more effective against some types of plants than others, eg, broadleaved plants vs grasses. Glyphosate [1071 -83-6] is representative of the nonselective herbicides used for total vegetable control. 

Metal Organics and Inorganics. The metal organic herbicides are arsenicals used for the selective, post-emergence control of grass and broadleaved weeds in cropland and noncroplands. These herbicides are particularly usehil for weed control in cotton and turf crops (2,296,294). CacodyUc acid is a contact herbicide used for nonselective weed control in cropland and noncropland (299). Ammonium sulfamate [7773-06-0] (AMS) is an inorganic herbicide used for control of woody plants and herbaceous perennials (2). 

Although the ratios have varied from year to year since 1979, the selective herbicides used in com production have accounted for approximately 21% of herbicide use on a per crop basis (24). Herbicide use in soybean and cotton production combined account for ca 23% of the selective herbicide market. Graminicides, which selectively kill grasses, constitute 40% of the total market, leaving a market share of approximately 16% for the nonselective herbicides. 

Alachlor zero 0.002 Eye, liver, kidney or spleen problems anemia increased risk of cancer Runoff from herbicide used on row crops... 

Dalapon 0.2 0.2 Minor kidney changes Runoff from herbicide used on rights of way... 

Dinoseb 0.007 0.007 Reproductive difficulties Runoff from herbicide used on soybeans and vegetables... 

Endothall 0.1 0.1 Stomach and intestinal problems Runoff from herbicide use... 

Chloroacetanilides are soil-applied herbicides used for pre- and early post-emergence control of annual grasses and broadleaf weeds in crops. Representative chloroacetanilide compounds, alachlor, acetochlor, and metolachlor, are extensively used worldwide. Other chloroacetanilides with limited usages include propachlor, bu-tachlor, metazachlor, pretilachlor, and thenylchlor. Public environmental concerns and government regulatory requirements continue to prompt the need for reliable methods to determine residues of these herbicides. There now exist a variety of analytical methods to determine residues of these compounds in crops, animal products, soil, and water. The chemical structures and major crops in which these compounds are used are summarized in Table 1. 

Stable in water and under light Bispyribac-sodium is a systemic post-emergence herbicide, used to control a broad range of weeds in rice... 

Use pattern Terbacil is a substituted uracil herbicide used primarily to control annual and perennial grass and broadleaved weeds in apple orchards, alfalfa, asparagus, mint and sugar cane. Other minor uses include blueberries, strawberries and seed grasses... 

Table 6 List of ions monitored for imidazolinone herbicides using in-source CID (HPLC/ESI-MS)...

The estimated cost of equipment, labor, and herbicides for weed control within a specific crop can be very expensive. For example, in 1980, cotton was planted on 5.2 million ha in the United States. The total cost for equipment, labor, and herbicides used to control weeds was estimated to be 547 million (20). Herbicides account for 32% of the total cost while equipment and labor costs were 34% each. 

Some of the metabolites arising from the breakdown of trifluraline (an herbicide used to treat cotton, soy, sunflowers, etc.) are far more stable and have a significant antibacterial expression. 

A serious and underestimated negative effect of herbicide use is acutely increased soil erosion. The lack of an herbaceous cover leaves the soil with no defense against wind, rain, and snowmelt. Erosion rapidly develops on slopes of just 1-2% when the soil has no covering. 

Herbicide use in forestry causes mineralization, thus decreasing the amount of organic compounds in the soil, as well as the overall nitrogen and calcium content. It is an immutable fact that pesticides negatively effect agricultural crops. And this influence is much more serious and varied than pesticide proponents believe. 

In fields where some weeds were cleared using herbicides, other, more herbicide-resistant, species have appeared, such as common horsetail, coltsfoot, foxtail, wild oats, false wheat, etc. As a result of herbicide use, scratchweed, which cannot be destroyed by any herbicide, is making inroads into cereal crops, and chamomile has taken over rapeseed [6]. Using herbicides on rice fields caused the spread of wild, pesticide-resistant, low-yield forms of red-grain rice. 

Used industrially as a chemical intermediate for pharmaceuticals and herbicides used in the manufacture of flame-resistant products used as a stabilizer for liquid sulfur trioxide. 

M.D. David, S. Campbell and Q.X.Li, Pressurized fluid extraction of nonpolar pesticides and polar herbicides using in situ derivatization. Anal. Chem. 72 (2000) 3665-3670. 

Uses Pre-emergence herbicide used in soil to control germinating broadleaf grasses and weeds in crops such as apples, cotton, grapes, pears, pineapples, and alfalfa sugar cane flowering depressant. 

Bentazone Acid 25057-89-0 2.55 1972 Herbicide A postemergence herbicide used for selective control of broadleaf weeds and sedges (a weed) in beans, rice, com, peanuts, mint, and others... 

Mecoprop Acid 7085-19-0 2.29 -1956 Herbicide A postemergence herbicide used to control broad-leaved weeds such as cleavers, chickweed, plantains, and clover... 

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