Herbicides, also commonly known as weed killers, are substances used to control undesired plants, also known as weeds. Selective herbicides control specific weed species while leaving the desired crop relatively unharmed, while non-selective herbicides kill plants indiscriminately. The combined effects of herbicides, nitrogen fertilizer, and improved cultivars has increased yields of major crops by three to six times from 1900 to 2000.
Glyphosate is a broad-spectrum systemic herbicide and crop desiccant. It is an organophosphorus compound, specifically a phosphonate, which acts by inhibiting the plant enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSP). Glyphosate-based herbicides are used to kill weeds, especially annual broadleaf weeds and grasses that compete with crops. Monsanto brought it to market for agricultural use in 1974 under the trade name Roundup. Monsanto's last commercially relevant United States patent expired in 2000.
Pesticides vary in their effects on bees. Contact pesticides are usually sprayed on plants and can kill bees when they crawl over sprayed surfaces of plants or other areas around it. Systemic pesticides, on the other hand, are usually incorporated into the soil or onto seeds and move up into the stem, leaves, nectar, and pollen of plants.
Pesticide residue refers to the pesticides that may remain on or in food, after they are applied to food crops. The maximum allowable levels of these residues in foods are stipulated by regulatory bodies in many countries. Regulations such as pre-harvest intervals also prevent harvest of crop or livestock products if recently treated in order to allow residue concentrations to decrease over time to safe levels before harvest.
Diphenylamine is an organic compound with the formula (C6H5)2NH. The compound is a derivative of aniline, consisting of an amine bound to two phenyl groups. The compound is a colorless solid, but commercial samples are often yellow due to oxidized impurities. Diphenylamine dissolves well in many common organic solvents, and is moderately soluble in water. It is used mainly for its antioxidant properties. Diphenylamine is widely used as an industrial antioxidant, dye mordant and reagent and is also employed in agriculture as a fungicide and antihelmintic.
Dicamba is a selective systemic herbicide first registered in 1967. Brand names for formulations of this herbicide include Dianat, Banvel, Diablo, Oracle and Vanquish. This chemical compound is a chlorinated derivative of o-anisic acid. It has been described as a "widely used, low-cost, environmentally friendly herbicide that does not persist in soils and shows little or no toxicity to wildlife and humans."
Trifluralin is a common pre-emergent selective herbicide, a dinitroaniline. With about 14 million pounds (6,400 t) used in the United States in 2001, and 3–7 million pounds (1,400–3,200 t) in 2012, it is one of the most widely used herbicides. Trifluralin is also used in Australia, and New Zealand, previously in the EU. Introduced in 1964, Trifluralin was the first organofluorine compound used as an agrochemical.
Bromacil is an organic compound with the chemical formula C9H13BrN2O2, commercially available as a herbicide. Bromacil was first registered as a pesticide in the U.S. in 1961, and by 1974 1,017,000 pounds (461,000 kg) was used annually in the US, largely by government and industry. It is used for brush control on non-cropland areas. It works by interfering with photosynthesis by entering the plant through the root zone and moving throughout the plant. Bromacil is one of a group of compounds called substituted uracils. These materials are broad spectrum herbicides used for nonselective weed and brush control on non-croplands, as well as for selective weed control on a limited number of crops, such as citrus fruit and pineapple. Bromacil is also found to be excellent at controlling perennial grasses.
Thiamethoxam is the ISO common name for a mixture of cis-trans isomers used as a systemic insecticide of the neonicotinoid class. It has a broad spectrum of activity against many types of insects and can be used as a seed dressing.
Chlorpropham or CIPC is a plant growth regulator and herbicide used as a sprout suppressant for grass weeds, alfalfa, lima and snap beans, blueberries, cane fruit, carrots, cranberries, ladino clover, garlic, seed grass, onions, spinach, sugar beets, tomatoes, safflower, soybeans, gladioli and woody nursery stock. It is also used to inhibit potato sprouting and for sucker control in tobacco. Chlorpropham is available in emulsifiable concentrate and liquid formulations.
2,4-Dichlorophenoxyacetic acid is an organic compound with the chemical formula Cl2C6H3OCH2CO2H. It is usually referred to by its ISO common name 2,4-D. It is a systemic herbicide that kills most broadleaf weeds by causing uncontrolled growth, but most grasses such as cereals, lawn turf, and grassland are relatively unaffected.
Benfluralin is a herbicide of the dinitroaniline class. The mechanism of action of benfluralin involves pre-emergent inhibition of mitosis, root and shoot development, same as trifluralin, from which benfluralin was developed in 1963.
Chlormequat is an organic compound with the formula ClCH
2CH
2N(CH
3)+
3 that is used as a plant growth regulator. It is typically sold as the chloride salt, chlormequat chloride (C5H13Cl2N), a colorless hygroscopic crystalline substance that is soluble in water and ethanol. It is an alkylating agent and a quaternary ammonium salt. Chlormequat is one of the onium-type growth regulators.
A pesticide, also called Plant Protection Product (PPP), which is a term used in regulatory documents, consists of several different components. The active ingredient in a pesticide is called “active substance” and these active substances either consist of chemicals or micro-organisms. The aims of these active substances are to specifically take action against organisms that are harmful to plants. In other words, active substances are the active components against pests and plant diseases.
Glyphosate-based herbicides are herbicides made of a glyphosate salt usually combined with other ingredients needed to stabilize the formula and allow penetration into plants. Roundup was the first glyphosate-based herbicide, developed by Monsanto in the 1970s. It is used most heavily on corn, soy, and cotton crops that have been genetically modified to be resistant to the herbicide. Some products include two active ingredients, such as Enlist Duo which includes 2,4-D as well as glyphosate. As of 2010, more than 750 glyphosate products were on the market. The names of inert ingredients used in glyphosate formulations are usually not listed on the product labels.
Prosulfocarb is a pre-emergent herbicide used agriculturally in Australia, the EU, Japan, New Zealand,, Morocco and Iran, for control of annual ryegrass and toad rush in wheat and barley crops. It was introduced to the EU in 1988 and is rapidly growing in use, with sales increasing by over 500% in France since 2008.
Nitralin is a selective pre-emergent dinitroaniline herbicide that is closely related to trifluralin, and released two years later in 1966. Today it is largely obsolete. It was used in the USA, France and Australia to control annual grasses and broad-leaved weeds, and was applied on vines, crops and turf.
Profluralin is a dinitroaniline herbicide used preëmergently to control annual grasses and broadleaf weeds, in cotton, soybeans, peanuts, sunflower, cabbage, cauliflower, tomato and others. Profluralin has largely fallen out of use. It rose out of the related, still in common use, trifluralin.
Chlornidine is a preemergent herbicide. It is a dinitroaniline used in China and India on soybeans, corn, cotton, sorghum, and peanuts.
Dinitramine is a preëmergent dinitroaniline herbicide incorporated into soil to control weeds for months after. It is no longer approved in the United States, and is not in the European Union, though in Iran it has been used to control annual grasses and broadleaf weeds in cotton and soybeans, as it was in the U.S. as of 1975, where it was also used on sunflower.
