Pesticides insect repellents

Use and exposure There are three forms of xylene meto-xylene, ortho-xyltnt, and para-xylene (m-, o-, and p-xylene). These different forms are referred to as isomers. Xylene is a colorless, sweet-smelling liquid that catches tire easily. It occurs naturally in petroleum and coal tar. Chemical industries produce xylene from petroleum. Xylene is used as a solvent in the printing, rubber, and leather industries. It is also used as a cleaning agent, a thinner for paint, and in paints and varnishes. It is found in small amounts in airplane fuel and gasoline. Xylene is used extensively in the manufacture of many other chemicals, such as plastics, synthetic fibers, pesticides, insect repellents, and leather goods. ... 

Substituted amides (not of the alkanolamide variety) are sold to diverse low volume markets. They have some utility in polymers such as polyethjiene, ethjiene-vinji acetate copolymers, acryUc polymers, PVC, polyamides, and polyesters. They have been found effective as pharmaceutical processiog aids, defoamers (qv), antimicrobials, pesticides, insect repellents, dispersion stabilizers, and corrosion inhibitors. 

Biological larvicides have been introduced for malaria and dengue control in many countries. Locally manufactured biological larvicides are available. Personal protection measures have been promoted by control programmes, including the use of insect repellents, mosquito coils, mats and aerosols. Household pesticide use is increasing in India, Indonesia, Sri Lanka and Thailand. 

SAFETY PROFILE Poison by intravenous route. Moderately toxic by ingestion and skin contact. Human systemic effects coma, convulsions, dermatitis, mydriasis (pupiUar dilation), nausea or vomiting, stiffness. An eye and skin irritant. Experimental reproductive effects by skin contact. Mutation data reported. Can cause central nervous system disturbances. A pesticide. DEET is the active ingredient in most commercial insect repellents. When heated to decomposition it emits toxic fumes of NO,. 

SAFETY PROFILE Moderately toxic by ingestion and intraperitoneal routes. Mildly toxic by inhalation. Experimental teratogenic and reproductive effects. Mutation data reported. An eye irritant. A pesticide and insect repellent. Combustible when exposed to heat or flame can react with oxidizing materials. To fight fire, use CO2, dry chemical. When heated to decomposition it emits acrid smoke and irritating fumes. See also ESTERS. 

The CBs used as pesticides are N-substituted esters of carbamic acid. CBs developed in the 1950s as insect repellents were found to have insecticidal activity, leading to the development of the napthyl CBs with high anti-ChE activity and selective toxicity against insects. One example is carbaryl it is widely used because of its low toxicity to mammals and its degradability. Aldicarb, a plant systemic, is more toxic than carbaryl. A few years ago aldicarb was associated with a July 4th holiday incident when West Coast residents complained of anticholinergic symptoms after eating aldicarb-contaminated watermelon. 

Naphthalene is commonly used in the manufacture of dyes, resins, and mothballs and may also be found in association with coal tar production and in wood preservatives. It is also used as a chemical intermediate in the synthesis of pharmaceuticals, insect repellents, and pesticides. 

Throughout history, various types of pests, such as insects, weeds, bacteria, rodents, and other biological organisms, have bothered humans or threatened human health. People have been nsing pesticides for thousands of years to try to control these pests. The Snmerians used sulfur to control insects and mites 5,000 years ago. The Chinese used mercury and arsenic compotmds to control body lice and other pests. The Greeks and Romans used oil, ash, sulfur, and other materials to protect themselves, their hvestock, and their crops from various pests. And people in various cultures have used smoke, salt, spices, and insect-repelling plants to preserve food and keep pests away. 

The biochemical reaction catalyzed by epoxygenase in plants combines the common oilseed fatty acids, linoleic or linolenic acids, with O2, forming only H2O and epoxy fatty acids as products (CO2 and H2O are utilized to make linoleic or linolenic acids). A considerable market currently exists for epoxy fatty acids, particularly for resins, epoxy coatings, and plasticizers. The U.S. plasticizer market is estimated to be about 2 billion pounds per year (Hammond 1992). Presently, most of this is derived from petroleum. In addition, there is industrial interest in use of epoxy fatty acids in durable paints, resins, adhesives, insecticides and insect repellants, crop oil concentrates, and the formulation of carriers for slow-release pesticides and herbicides (Perdue 1989, Ayorinde et al. 1993). Also, epoxy fatty acids can readily and economically be converted to hydroxy and dihydroxy fatty acids and their derivatives, which are useful starting materials for the production of plastics as well as for detergents, lubricants, and lubricant additives. Such renewable derived lubricant and lubricant additives should facilitate use of plant/biomass-derived fuels. Examples of plastics that can be produced from hydroxy fatty acids are polyurethanes and polyesters (Weber et al. 1994). As commercial oilseeds are developed that accumulate epoxy fatty acids in the seed oil, it is likely that other valuable products would be developed to use this as an industrial chemical feedstock in the future. 

MAJOR USES Used in the manufacture of solid rocket propellants lacquers plastics resins safety glasses rubber coating agents molding powders insect repellants pesticides solvent and plasticizer for cellulose acetate and cellulose acetate butyrate compositions. 

Products and Uses Insect repellents, solvent, and film former. Various uses, primarily as a pesticide or repellent. 

Pesticides are used to control cockroaches and other imdesirable pests. They come in many forms, such as ant powders, insect repellents, and slug pellets. They are used in the environment and in the household to ensure that our food supplies are protected while they are growing and while they are stored in our fruit bowls and vegetable racks. Pesticides are effective pest killers, but are also harmful to humans therefore, the use of these materials is covered by legislation and only those permitted within a country can be used legitimately at a controlled level. 

This Section (6.4) is divided into (6.4.1) insecticides, with further data on insect repellants and ectoparasites, (6.4.2) fungicides, (6.4.3) herbicides (weed killers), and (6.4.4) other pesticides, including defoliants, plant antiviral agents, anthelmintics, molluscicides, and rodenticides. 

The two most important varieties of pesticides are insecticides and herbicides. There are also other crop-protection agents such as fungicides, acaricides, rodenticides, avicides, bactericides, nemati-cides, molluscides, fumigants, chemo-sterilants, insect repellents and other specialised products. It is usually convenient to group, with these, certain crop-improvement agrochemicals which are not fertilisers. 

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