Herbicides and insecticides

Water-Soluble Films. Water-soluble films can be produced from such polymers as poly(vinyl alcohol) (PVOH), methylceUulose, poly(ethylene oxide), or starch (qv) (see Cellulose ethers Polyethers Vinyl polymers). Water-soluble films are used for packaging and dispensing portions of detergents, bleaches, and dyes. A principal market is disposable laundry bags for hospital use. Disposal packaging for herbicides and insecticides is an emerging use. 

Another significant use of 3-methylphenol is in the production of herbicides and insecticides. 2-/ f2 -Butyl-5-methylphenol is converted to the dinitro acetate derivative, 2-/ f2 -butyl-5-methyl-4,6-dinitrophenyl acetate [2487-01 -6] which is used as both a pre- and postemergent herbicide to control broad leaf weeds (42). Carbamate derivatives of 3-methylphenol based compounds are used as insecticides. The condensation of 3-methylphenol with formaldehyde yields a curable phenoHc resin. Since 3-methylphenol is trifunctional with respect to its reaction with formaldehyde, it is possible to form a thermosetting resin by the reaction of a prepolymer with paraformaldehyde or other suitable formaldehyde sources. 3-Methylphenol is also used in the production of fragrances and flavors. It is reduced with hydrogen under nickel catalysis and the corresponding esters are used as synthetic musk (see Table 3). 

In many respects, crop production has advanced little in the last two decades. More tools (herbicides and insecticides) are available for use by producers, but in many cases we have not fully utilized lessons learned earlier. Residue management seems to be one of those cases. In no-till agriculture, residue management techniques will have to be developed—by engineering, chemical, or biological means—for the system to function. 

Some azolides are distinguished by their practical applications, extending from their potential as fungicides, herbicides, and insecticides to their utility as textile auxiliaries, antiflammatory agents, or phase-transfer catalysts. The various azolides of these properties have been compiled below in five groups. 

Pesticides are one of the main environmental contaminants of the 20th Century. Only a small amount of the pesticides used actually reaches their targets. About 3% of herbicides and insecticides do so the rest is lost, falling on untargeted plants and animals, and into bodies of water. In other calculations, pesticides reach only about 0.1% of their targets. 

Used in the production of carbamates that are used to synthesize dyes, drugs, veterinary medicines, herbicides, and insecticides as a solvent in the photographic industry used as a stabilizer for PVC. 

Hanson, W.R. 1952. Effects of some herbicides and insecticides on biota of North Dakota marshes. Jour. Wildl. Manage. 16 299-308. 

Pesticides in wastewaters come typically from point sources of contamination such as disposal sites and landfills where industrial or agricultural wastes are buried without any consideration, as well as discharges from industrial effluents from pesticide production plants. Furthermore, nonpoint sources derived from regular agricultural activities, especially in intensive agricultural areas, and accidental spills can also be significant. Urban use of pesticides is also possible in large cities where the use of herbicides and insecticides may result in runoff into the sewers. These sewers in turn may expel pesticides into wastewater treatment plants (WWTPs). 

Another growing technique is super-critical fluid chromatography. Recent references to soil analysis include the following applications aliphatic hydrocarbons, polyaromatic hydrocarbons, polychlorobiphenyls, dioxins, alkyl and aryl phosphates, chloro, organophosphorus, triazine, substituted urea, phenoxy acetic acid, Dacthal herbicides and insecticides and mixtures of herbicides and pesticides and mixtures of organic compounds. 

Kadoum AM, Mock DE. 1978. Herbicide and insecticide residues in tailwater pits Water and pitottom soil from irrigated corn and sorghum fields. J Agric Food Chem 26(1) 45-50. 

In part, this insistence was linked to a growing understanding of just how dangerous many early herbicides and insecticides were. Lead arsenate is typical in this sense. As a chemical widely advocated for lawn use, despite a growing acknowledgment of its associated health risks, it would set the precedent for the ambivalence associated with lawn care inputs, those inputs we use and desire despite anxieties and concerns. 

This marketing revolution has proven successful by all accounts. Consumer spending on lawn chemicals has increased in many markets, and has remained steady despite declines in other areas of herbicide and insecticide sales. ... 

Mersch-Sundermann V, HofmeisterA, Mueller G, etal. 1989. [Examination of mutagenicity of organic microcontaminations of the environment. III. Communication The mutagenicity of selected herbicides and insecticides with the SOS-chromotest]. ZbI Hyg 189 135-146. (German). 

Uses Dormant ovicidal spray for fruit trees (highly phototoxic and cannot be used successfully on actively growing plants) selective herbicide and insecticide. 

Refined borax (Na B Op is an additive in laundry products such as soaps and water-softening compounds. Also used for cosmetics, body powders, and the manufacture of paper and leather. Borax is an environmentally safe natural herbicide and insecticide. 

Chemical compounds classified as pesticides (fungicides, herbicides and insecticides) total over 500. Others used as rodenticides, desiccants, defoliants, etc., increase that number. Agricultural uses include all crops and livestock on farms, plus those used as seed treatments, in greenhouses, parks, golf courses, nurseries and lavms in urban areas. Chemicals are applied by farmers, industry, or institutional employees, commercial applicators and individual citizens. 

The European Community has developed a very comprehensive regulatory framework, which regulates the marketing and use of PPPs and their residues in food (EU 2006d,f). Essentially, PPPs are the pesticides, e.g., fungicides, herbicides, and insecticides, aimed at protecting plants. 

This phenomenon of self-emulsification was first observed by Johannes Gad in 1878 when he gently layered a solution of lauric acid on top of an aqueous alkaline solution, thereby making a soap in situ but also forming an emulsion without the aid of external agitation. A laboratory curiosity for the next 50 or so years, the principle became recognized as being valuable for the formulation of herbicides and insecticides such as DDT. The concentrate could be reconstituted with ditch water and sprayed without the need to carry water to the site. 

Fairchild, J.F., Lapoint, T.W. and Schwartz, T.R. (1994) Effects of an herbicide and insecticide mixture in aquatic mesocosms. Arch Environ Contam Toxicol, 27, 527-533. 

The next group of compounds that we want to look at are derivatives of carbamic acid (HO-CO-NH2), that is, the carbamates. Carbamates are widely used as herbicides and insecticides. The carbamate function exhibits both an ester and an amide-type functionality (Montgomery, 1997) ... 

In the United States, farmers use about 100 million pounds of fungicides annually, meaning fungicides rank third after herbicides and insecticides in the amounts used. An example of a fungicide is thiram, widely used on fruits and vegetables and shown in Figure 15-23. 

The lipids of some organisms, such as Tetrahymena, contain aminoethylphosphonate, a compound with a C-P bond (Chapter 8). There are also many other naturally occurring phosphono compounds and huge quantities of synthetic phosphonates, present in detergents, herbicides, and insecticides, are metabolized by bacteria 297 Here we will consider only one step in the biosynthesis of phosphonates, the conversion of PEP into phosphonopyruvate (Eq. 13-54), a reaction catalyzed by PEP mutase. The phospho group is moved... 

Broad range of herbicides and insecticides (atrazine, bromacil, carbofuran, 2-4- D, DDT, diuron, malathion, methyl parathion, simazine)... 

Sun, Y. and J.J. Pignatello (1993). Activation of hydrogen peroxide by iron(III) chelates for abiotic degradation of herbicides and insecticides in water. J. Agile. Food Chem., 41 308-312. 

Thurman, E.M., K.C. Bastian, and Tony Mollhagan (2000). Occurrence of cotton herbicides and insecticides in Playa Lakes of the high plains of west Texas. Sci. Total Environ., 248 189-200. 

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