![]() A virus lethality study performed in 1977 demonstrated that a particular pesticide did not increase the lethality of the virus. The application of pest control agents is usually carried out by dispersing the chemical in an (often hydrocarbon-based) solvent- surfactant system to give a homogeneous preparation. : 335 Many commonly used pesticides are not included in these families, including glyphosate. : 300 Triazines interfere with photosynthesis. The phenoxy and benzoic acid herbicides function similar to plant growth hormones, and grow cells without normal cell division, crushing the plant's nutrient transport system. Phenoxy compounds tend to selectively kill broad-leaf weeds rather than grasses. 2,4-D), triazines (e.g., atrazine), ureas (e.g., diuron), and Chloroacetanilide (e.g., alachlor). Prominent families of herbicides include phenoxy and benzoic acid herbicides (e.g. : 136–137 Thiocarbamate and dithiocarbamates are subclasses of carbamates. Organophosphates are quite toxic to vertebrates and have in some cases been replaced by less toxic carbamates. Both operate through inhibiting the enzyme acetylcholinesterase, allowing acetylcholine to transfer nerve impulses indefinitely and causing a variety of symptoms such as weakness or paralysis. : 239–240 Organophosphate and carbamates largely replaced organochlorines. Their toxicities vary greatly, but they have been phased out because of their persistence and potential to bioaccumulate. They operate by disrupting the sodium/potassium balance of the nerve fiber, forcing the nerve to transmit continuously. Organochlorine hydrocarbons (e.g., DDT) could be separated into dichlorodiphenyl ethanes, cyclodiene compounds, and other related compounds. Prominent insecticide families include organochlorines, organophosphates, and carbamates. Many pesticides can be grouped into chemical families. These include the pyrethroids, rotenoids, nicotinoids, and a fourth group that includes strychnine and scilliroside. Plant-derived pesticides, or " botanicals", have been developing quickly. Biopesticides include microbial pesticides and biochemical pesticides. Pesticides can be classified by target organism (e.g., herbicides, insecticides, fungicides, rodenticides, and pediculicides – see table), chemical structure (e.g., organic, inorganic, synthetic, or biological (biopesticide), although the distinction can sometimes blur), and physical state (e.g. Also used as substances applied to crops either before or after harvest to protect the commodity from deterioration during storage and transport. The term includes substances intended for use as a plant growth regulator, defoliant, desiccant, or agent for thinning fruit or preventing the premature fall of fruit. The Food and Agriculture Organization (FAO) has defined pesticide as:Īny substance or mixture of substances intended for preventing, destroying, or controlling any pest, including vectors of human or animal disease, unwanted species of plants or animals, causing harm during or otherwise interfering with the production, processing, storage, transport, or marketing of food, agricultural commodities, wood and wood products or animal feedstuffs, or substances that may be administered to animals for the control of insects, arachnids, or other pests in or on their bodies. Along with these benefits, pesticides also have drawbacks, such as potential toxicity to humans and other species. Target pests can include insects, plant pathogens, weeds, molluscs, birds, mammals, fish, nematodes (roundworms), and microbes that destroy property, cause nuisance, or spread disease, or are disease vectors. In general, a pesticide is a chemical (such as carbamate) or biological agent (such as a virus, bacterium, or fungus) that deters, incapacitates, kills, or otherwise discourages pests. As an example, the fungus Alternaria solani is used to combat the aquatic weed Salvinia. Most pesticides are intended to serve as plant protection products (also known as crop protection products), which in general, protect plants from weeds, fungi, or insects. The most common of these are herbicides, which account for approximately 50% of all pesticide use globally. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampricide. Pesticides are substances that are meant to control pests. A Lite-Trac four-wheeled self-propelled crop sprayer spraying pesticide on a field
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