Agrochemicals

GreatVista Chemicals is engaged in the marketing of crop protection products such as pesticides, insecticides, herbicides, fungicides, miticides, and fertilizers.

Pesticide is biological, physical, or chemical agent used to kill plants or animals that are harmful to people; in practice, the term pesticide is often applied only to chemical agents. Various pesticides are known as insecticides, nematicides, fungicides, herbicides, and rodenticides, i.e., agents primarily effective against insects, nematodes (or roundworms), fungi, weeds, and rodents, respectively. Among the biological agents, parasites and predators feed on pests; pathogens sicken them. Physical agents crush, wound, smother, or otherwise injure pests. Chemical pesticides are usually contact, stomach, or fumigant poisons. Contact poisons may have immediate or delayed effects after physical contact with a pest. DDT, the use of which is now illegal in many places, is both a contact and a stomach poison. Fumigants, which may initially have the form of a solid, liquid, or gas, kill pests while in a gaseous state. For example, paradichlorobenzene, used against moths, comes as a solid cake that vaporizes when exposed to air. Some insecticides and fungicides are systemic, i.e., they are translocated by a plant from the area of application to other plant parts, where they affect only pests that feed on the crop. Two rodenticides that are relatively selective and reasonably safe are red squill and warfarin. Other rodenticides include arsenic compounds, strychnine, and ANTU. The most important nematicides presently in use are 1,3-dichloropropene and 1,2-dibromoethane. Pesticides are applied in various forms: wet sprays, dusts, atomizable fluids, low pressure aerosols, smokes, and seed dressings. Because of concern about their harmful effects on humans and on ecological systems, chemical pesticides undergo exhaustive and expensive trials prior to government registration and release. Efforts are being made to reduce chemical-pesticide use in favor of Integrated Pest Management (IPM), biological controls, and plant-breeding for inherent pest resistance.

Fungicide is any substance used to destroy Fungi. Sulfur compounds, long used to destroy fungi on plants, have been supplemented for some time by other chemicals, especially by compounds of copper, such as Bordeaux mixture. Organic salts of iron, zinc, and mercury are also synthesized as fungicides. Fungicides, including formaldehyde, are applied also to seeds and soil for the destruction of vegetative spores. Plant fungicides are usually applied by spraying or dusting. Fungicides used on wood, including creosote, prevent dry rot, and certain compounds are used to make fabrics resistant to mildews. Antibiotic and sulfa drugs are used for human fungus diseases as well as for fungus diseases of plants. Most agricultural fungicides are preventive; those applied after infection are called eradicant, or contact, fungicides. In the United States, fungicides must be registered with the Food and Drug Administration and must conform to specifications; e.g., they must control the disease without injuring the plant and must leave no poisonous residue on edible crops.

Herbicide is chemical compound that kills plants or inhibits their normal growth. A herbicide in a particular formulation and application can be described as selective or nonselective. In agriculture, selective herbicides are often used instead of tillage, or in combination with tillage and other agronomic practices, to control weeds without damaging crops. For these low-till or no-till systems, scientists are using biotechnology to develop crop varieties with increased tolerance for herbicides. Nonselective herbicides, toxic to all plants, are used where complete control of plant growth is required. Contact herbicides kill only the parts of the plant they touch; systemic herbicides are absorbed by foliage or roots and translocated to other parts of the plant. Some herbicides, mixed into the soil, will kill germinating seeds and small seedlings. Early chemical herbicides were inorganic compounds. Herbicides such as ashes, common salts, and bittern have been used in agriculture since ancient times. Observation in 1896 that Bordeaux mixture, a fungicide, also provided control of certain weeds, led to the use of copper sulfate as a selective weed killer to control charlock in cereals. By 1900, solutions of sulfuric acid, iron sulfate, copper nitrate, and ammonium and potassium salts were known to act as selective herbicides; soon thereafter sodium arsenite solutions became the standard herbicides, and they were used in large quantities until about 1960. Other popular inorganic herbicides include ammonium sulfamate, carbon bisulfide, sodium chlorate, sulfuric acid solutions, and formulations containing borate. Organic herbicides began in earnest with dinitrophenol compounds in 1932. A breakthrough occurred in the 1940s with 2,4-D (2,4-dichlorophenoxyacetic acid), a compound similar to plant hormones, which is a highly selective systemic herbicide when used in very small quantities. 2,4-D was quickly adopted to control broadleaved weeds in corn, sorghum, small grains, and grass pastures, as well as in lawns and other ornamental turf. The phenoxyaliphatic acids and their derivatives, another major group of organic herbicides, succeeded because of their selectivity and ease of translocation. Other groups of organic herbicides include organic arsenicals, substituted amides and ureas, nitrogen heterocyclic acids, phenol derivatives, triazines, and sulfonylureas.

Fertilizer is organic or inorganic material containing one or more of the nutrients—mainly nitrogen, phosphorus, and potassium, and other essential elements required for plant growth. Added to the soil or other medium, fertilizers provide plant nutrients that are naturally lacking or that have been removed by harvesting or grazing, or by physical processes such as leaching or erosion. Organic fertilizers include animal and green manure, fish and bone meal, and compost. Microorganisms in the soil decompose organic material, making its elements available for use by plants. Inorganic or artificial fertilizers (also called chemical or mineral fertilizers) are formulated in appropriate concentrations and combinations for various crops and growing conditions. The most popular inorganic fertilizers include: anhydrous ammonia, a gas that is 82% nitrogen; urea, a solid compound containing 46% nitrogen; superphosphate; and diammonium phosphate, containing 18% nitrogen and 46% phosphate. Fertilizers may be spread over the soil surface or plowed under, drilled into deep or shallow layers of the soil, applied in bands under the rows where the seeds are to be sown, drilled into the bands at the time of planting, or side-dressed between planted rows. Nitrogen fertilizer washing from farms into surface waters promotes overgrowth of aquatic vegetation, which degrades water quality and can cause eutrophication. Use of inorganic nitrogen suppresses nitrogen- fixing soil bacteria, making agriculture increasingly dependant on artificial fertilizer.