insecticide n : a chemical used to kill insects [syn: insect powder]
- A substance used to kill insects
An insecticide is a pesticide used against insects in all developmental forms. They include ovicides and larvicides used against the eggs and larvae of insects respectively. Insecticides are used in agriculture, medicine, industry and the household. The use of insecticides is believed to be one of the major factors behind the increase in agricultural productivity in the 20th century. Nearly all insecticides have the potential to significantly alter ecosystems; many are toxic to humans; and others are concentrated in the food chain. It is necessary to balance agricultural needs with environmental and health issues when using insecticides.
Classes of agricultural insecticidesThe classification of insecticides is done in several different ways:
- Systemic insecticides are incorporated by treated plants. Insects ingest the insecticide while feeding on the plants.
- Contact insecticides are toxic to insects brought into direct contact. Efficacy is often related to the quality of pesticide application, with small droplets (such as aerosols) often improving performance.
- Natural insecticides, such as nicotine and pyrethrum, are made by plants as defences against insects. Nicotine based insecticides have been barred in the U.S. since 2001 to prevent residues from contaminating foods. http://pmep.cce.cornell.edu/profiles/insect-mite/mevinphos-propargite/nicotine/nicotine_tol_1201.html
- Inorganic insecticides are manufactured with metals and include arsenates copper- and fluorine compounds, which are now seldom used, and sulfur, which is commonly used.
- Organic insecticides are synthetic chemicals which comprise the largest numbers of pesticides available for use today.
- Mode of action -- how the pesticide kills or inactivates a pest -- is another way of classifying insecticides. Mode of action is important in predicting whether an insecticide will be toxic to unrelated species such as fish, birds and mammals.
Heavy metals, e.g. lead, mercury, arsenic, as well as plant toxins such as nicotine have been used for many years. Various plants have been used as folk insecticides for centuries, including tobacco and pyrethrum. Some farmers are reporting successfully using spray of crudely fermented alcohol as an effective insecticide.
OrganochloridesWith the rise of the modern chemical industry it was possible to form organochlorides, such as chlorinated hydrocarbons. The organochlorides used in chemical warfare tend to be more potent electrophiles than those used as insecticides. For instance mustard gas (sulfur mustard, HD) is a potent alklating agent which uses neighbouring group participation of the sulfur to make the alkyl chloride a stronger electrophile. It is likely that the chlorine in DDT is used to tune the lipophilicity of the compound, and to alter the shape and electrostatic effects involved in the interactions of the insecticide and the biomolecules in the target organism. For instance DDT works by opening the sodium channels in the nerve cells of the insect.
OrganophosphatesThe next large class was the organophosphates, both the insecticides and the chemical warfare agents (such as sarin, tabun, soman and VX) work in the same way. All these compounds bind to acetylcholinesterase and other cholinesterases. This results in disruption of nervous impulses, killing the insect or interfering with its ability to carry on normal functions. Carbamate insecticides have similar toxic mechanisms but have a much shorter duration of action and are thus somewhat less toxic.
Organophosphates have an additive toxic effect to wildlife, so multiple exposures to the chemicals amplifies the toxicity.
Sprayed insecticides may drift from the area to which it is applied and into wildlife areas, especially when it is sprayed aerially. in which worker bees from a beehive or Western honey bee colony abruptly disappear. Loss of pollinators will mean a reduction in crop yields. (bug found in stored cereal)
- International Pesticide Application Research Centre (IPARC)
- Pestworld.org - Official site of the National Pest Management Association
- Classification of insecticides
- Streaming online video about efforts to reduce insecticide use in rice in Bangladesh. on Windows Media Player, on Real Player
- How Insecticides Work - Has a thorough explanation on how insecticides work.
- University of California Integrated pest management program
insecticide in Arabic: مبيد حشرات
insecticide in Breton: Dilastezer
insecticide in Bulgarian: Пестицид
insecticide in Catalan: Insecticida
insecticide in Czech: Insekticid
insecticide in Danish: Insekticid
insecticide in German: Insektizid
insecticide in Estonian: Insektitsiid
insecticide in Spanish: Insecticida
insecticide in Esperanto: Pesticido
insecticide in French: Insecticide
insecticide in Galician: Pesticida
insecticide in Italian: Pesticida
insecticide in Hebrew: הדברת מזיקים
insecticide in Lithuanian: Insekticidas
insecticide in Dutch: Insecticide
insecticide in Japanese: 殺虫剤
insecticide in Norwegian: Insektmiddel
insecticide in Polish: Insektycydy
insecticide in Portuguese: Inseticida
insecticide in Romanian: Pesticide
insecticide in Russian: Инсектициды
insecticide in Simple English: Insecticide
insecticide in Slovenian: Pesticid
insecticide in Serbian: Инсектициди
insecticide in Finnish: Insektisidi
insecticide in Swedish: Bekämpningsmedel
insecticide in Vietnamese: Thuốc trừ sâu
insecticide in Ukrainian: Інсектициди
insecticide in Chinese: 殺蟲劑
aborticide, acaricide, anthelmintic, antibiotic, antiseptic, bug bomb, carbamate insecticide, chemosterilant, chlorinated hydrocarbon insecticide, contact poison, defoliant, disinfectant, eradicant, fratricide, fumigant, fungicide, genocide, germicide, herbicide, homicide, infanticide, insect powder, matricide, microbicide, miticide, organic chlorine, organic phosphate insecticide, parricide, patricide, pesticide, poison, rat poison, regicide, roach paste, roach powder, rodenticide, sororicide, stomach poison, suicide, systemic, systemic insecticide, toxic, toxicant, toxin, uxoricide, venin, venom, vermicide, virus, weed killer