Pesticide resistance is the adaptation of pest species targeted by a pesticide resulting in decreased susceptibility to that chemical. An adaptation is a characteristic of an Organism that has been favored by Natural selection and A pesticide is a substance or mixture of substances used to kill a pest. In other words, pests develop a resistance to a chemical through artificial selection; after they are exposed to a pesticide for a prolonged period it no longer kills them as effectively. Artificial selection is the intentional breeding for certain traits or combinations of traits over others and is synonymous with " Selective breeding " The most resistant organisms are the ones to survive and pass on their genetic traits to their offspring. Genetics (from Ancient Greek grc-Latn genetikos, “genitive” and that from grc-Latn genesis, “origin” a discipline of Biology, is [1]
More specific definitions of pesticide resistance often apply to particular classes of pesticides. Manufacturers of pesticides tend to prefer a definition that is dependent on failure of a product in a real situation, sometimes called field resistance. For example, the Insecticide Resistance Action Committee (IRAC) definition of insecticide resistance is 'a heritable change in the sensitivity of a pest population that is reflected in the repeated failure of a product to achieve the expected level of control when used according to the label recommendation for that pest species'. An insecticide is a Pesticide used against Insects in all developmental forms [2]
Pesticide resistance is increasing in occurrence. In the 1940s, farmers in the USA lost 7% of their crops to pests, while since the 1980s, the percentage lost has increased to 13, even though more pesticides are being used. The 1940s decade ran from 1940 to 1949 Events and trends The 1940s was a period between the radical 1930s and the conservative 1950s which also leads the period to be The United States of America —commonly referred to as the The 1980s was the decade spanning from January 1 1980 to December 31 1989. [1] Over 500 species of pests have developed a resistance to a pesticide. [3] Other sources estimate the number to be around 1000 species since 1945. Year 1945 ( MCMXLV) was a Common year starting on Monday (link will display the full calendar [4]
Rachel Carson predicted the phenomenon in her 1962 book Silent Spring. Rachel Louise Carson (May 27 1907 – April 14 1964 was an American marine biologist and Nature writer whose writings are credited with advancing the global Silent Spring is a book written by Rachel Carson and published by Houghton Mifflin in September 1962 [1]
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Factors
Pesticides that fail to break down quickly and remain in the area contribute to resistance even after they are no longer being applied. [5]
In response to pesticide resistance, farmers may resort to increased use of pesticides, exacerbating the problem. [6] In addition, when pesticide use decreases populations of species that feed on or compete with pests, their populations expand further, requiring more pesticides. [6] This is sometimes referred to as pesticide trap,[6] or a pesticide treadmill, since farmers are continually paying more for less benefit. [4]
Insect predators and parasites which live on other insects are much less likely to develop resistance than insects such as mosquitoes and those that feed on plants, which can compound the problem because these species normally keep pest populations in check. [5] But resistant predators of pest species can be bred in laboratories, which can help keep pest populations down. [5]
The less sources of food a pest has the more likely it is to develop resistance, because it is exposed to higher concentrations of pesticides and has less opportunity to breed with populations that have not been exposed. [5] Other factors in the speed with which a species develops resistance is generation time and fecundity (shorter generations and more offspring lead to resistance more quickly). The doubling time is the period of time required for a quantity to double in size or value Fecundity, derived from the word fecund, generally refers to the ability to Reproduce. [5]
Examples
Resistance has developed in a variety of different pest species:
- The first known case of pesticide resistance occurred with DDT in Sweden in 1946 shortly after the chemical was first used. "Sverige" redirects here For other uses see Sweden (disambiguation and Sverige (disambiguation. Year 1946 ( MCMXLVI) was a Common year starting on Tuesday (link will display full 1946 calendar of the Gregorian calendar. [5]
- In the US, studies have shown that fruit flies that infest orange groves were becoming resistant to malathion, a pesticide used to kill them. Malathion is an Organophosphate Parasympathomimetic which binds irreversibly to Cholinesterase. [7]
- In Hawaii and Japan, the diamondback moth developed a resistance to Bacillus thuringiensis about three years after it began to be used heavily. The State of Hawaii ( or həˈwaɪʔiː Hawaiian: Mokuāina o Hawaii) is a state in the United States located on an Archipelago in the For a topic outline on this subject see List of basic Japan topics. The Diamondback moth ( Plutella xylostella) sometimes called cabbage moth, is a European moth believed to originate in the Mediterranean region that has since spread Bacillus thuringiensis is a Gram-positive, soil dwelling Bacterium of the Genus Bacillus. [5]
- In England, rats in certain areas have developed such a strong resistance to rat poison that they can consume up to five times as much of it as normal rats without dying. [1]
- DDT is no longer effective in preventing malaria in some places, a fact which contributed to a resurgence of the disease. Malaria is a vector -borne Infectious disease caused by Protozoan Parasites It is widespread in tropical and subtropical regions including [4]
Multiple resistance
Multiple resistance is the phenomenon in which a pest is resistant to more than one class of pesticides. [5] This can happen if one pesticide is used until pests display a resistance and then another is used until they are resistant to that one, and so on. [5] Cross resistance, a related phenomenon, occurs when the genetic mutation that made the pest resistant to one pesticide also makes it resistant to other pesticides, especially ones with similar mechanisms of action or ones in the same class. [5]
Physiology
Frequently a pest becomes resistant to a pesticide because it develops physiological changes that protect it from the chemical. [5] In some cases, a pest may gain an increased number of copies of a gene, allowing it to produce more of a protective enzyme that breaks down the pesticide into less toxic chemicals. History See also History of genetics The existence of genes was first suggested by Gregor Mendel (1822-1884 who in the 1860s studied inheritance Enzymes are Biomolecules that catalyze ( ie increase the rates of Chemical reactions Almost all enzymes are Proteins [5] Such enzymes include esterases, glutathione transferases, and mixed microsomal oxidases. An esterase is a Hydrolase Enzyme that splits Esters into an Acid and an Alcohol in a Chemical reaction with water The glutathione S -transferase (GST family of Enzymes comprises a long list of Cytosolic, Mitochondrial, and Microsomal [5] Alternately, the number of biochemical receptors for the chemicals may be reduced in the pest, or the receptor may be altered, reducing the pest's sensitivity to the compound. In Biochemistry, a receptor is a Protein molecule embedded in either the Plasma membrane or Cytoplasm of a cell to which a mobile signaling [5] Behavioral resistance has also been described for some chemicals; for example, some Anopheles mosquitoes developed a preference for resting outside that prevented them from coming in contact with pesticide sprayed on interior walls. [8]
Blowfly maggots produce an enzyme that confers resistance to organochloride insecticides. Scientists have researched ways to use this enzyme to break down pesticides in the environment, which would detoxify them and prevent harmful environmental effects. [9] Later they discovered a similar enzyme produced by soil bacteria that also breaks down organochloride insecticides but which works faster and remains stable in a variety of conditions. Applications The simplest form of organochlorides are chlorinated Hydrocarbons These consist of simple Hydrocarbons in which one or more hydrogen atoms have [9] The product, called Landguard is used in Australia to decontaminate spray equipment, soil and water after pesticide spraying and spills. [9]
Management
Pest resistance to a pesticide is commonly managed through pesticide rotation, which involves alternating among pesticide classes with different modes of action to delay the onset of or mitigate existing pest resistance. [10] Different pesticide classes may have different effects on a pest. [10] The U. S. Environmental Agency (EPA or USEPA) designates different classes of fungicides, herbicides and insecticides. Pesticide manufacturers may, on product labeling, require that no more than a specified number of consecutive applications of a pesticide class be made before alternating to a different pesticide class. This manufacturer requirement is intended to extend the useful life of a product.
Tankmixing pesticides is the combination of two or more pesticides with different modes of action in order to improve individual pesticide application results and delay the onset of or mitigate existing pest resistance. [11]
Another strategy is to avoid using pesticides more often than necessary. [11]
See also
References
- ^ a b c d PBS (2001), Pesticide resistance. Antibiotic resistance is the ability of a Microorganism to withstand the effects of Antibiotics. Vavilovian mimicry (also crop mimicry or weed mimicry) is a form of Mimicry in Plants where a Weed comes to share one or more characteristics Retrieved on September 15, 2007. Events 668 - Eastern Roman Emperor Constans II is assassinated in his bath at Syracuse Italy. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century.
- ^ Insecticide Resistance Action Committee (2007), Resistance Definition. Retrieved on September 15, 2007. Events 668 - Eastern Roman Emperor Constans II is assassinated in his bath at Syracuse Italy. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century.
- ^ grapes. msu. edu. How pesticide resistance develops. Excerpt from: Larry Gut, Annemiek Schilder, Rufus Isaacs and Patricia McManus. Fruit Crop Ecology and Management, Chapter 2: "Managing the Community of Pests and Beneficials. " Retrieved on September 15, 2007. Events 668 - Eastern Roman Emperor Constans II is assassinated in his bath at Syracuse Italy. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century.
- ^ a b c Miller GT (2004), Sustaining the Earth, 6th edition. Thompson Learning, Inc. Pacific Grove, California. Chapter 9, Pages 211-216.
- ^ a b c d e f g h i j k l m n Daly H, Doyen JT, and Purcell AH III (1998), Introduction to insect biology and diversity, 2nd edition. Oxford University Press. New York, New York. Chapter 14, Pages 279-300.
- ^ a b c Marten, Gerry “Non-pesticide management” for escaping the pesticide trap in Andrah Padesh, India. ecotippingpoints. org. Retrieved on September 17, 2007. Events 1176 - The Battle of Myriokephalon is fought 1462 - The Battle of Świecino (or Battle of Żarnowiec Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century.
- ^ Doris Stanley (January 1996), Natural product outdoes malathion - alternative pest control strategy. Retrieved on September 15, 2007. Events 668 - Eastern Roman Emperor Constans II is assassinated in his bath at Syracuse Italy. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century.
- ^ Berenbaum M (1994) Bugs in the System. Perseus Books, New York.
- ^ a b c Marino M. (August 2007), Blowies inspire pesticide attack: Blowfly maggots and dog-wash play starring roles in the story of a remarkable environmental clean-up technology. Solve, Issue 12. CSIRO Enquiries. Retrieved on 2007-10-03. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 42 BC - First Battle of Philippi: Triumvirs Mark Antony and Octavian fight an indecisive battle with Caesar's
- ^ a b Graeme Murphy (December 1 2005), Resistance Management - Pesticide Rotation. Ontario Ministry of Agriculture, Food and Rural Affairs. Retrieved on September 15, 2007
- ^ a b Chris Boerboom (March 2001), Glyphosate resistant weeds. Events 668 - Eastern Roman Emperor Constans II is assassinated in his bath at Syracuse Italy. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Weed Science - University of Wisconsin. Retrieved on September 15, 2007
External links
- IRAC, Insecticide Resistance Action Committee
- FRAC, Fungicide Resistance Action Committee
- RRAC, Rodenticide Resistance Action Committee
- HRAC, Herbicide Resistance Action Committee
- UK Resistance Action groups
- Arthropod Pesticide Resistance Database
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