Pesticides

A plant protection product is a substance emitted in a culture to combat harmful organisms. It is a generic term which includes insecticides, fungicides, herbicides, parasiticides. They respectively tackle insect pests, mushroom, 'weeds' and parasitic worms.

They therefore include "phytosanitary" substances or "plant protection"..

In a wider sense, as the European regulatory, This can be the growth regulators, or substances that meet public health problems (for example cockroaches in homes), public health (insect parasites lice, bullets or disease vectors such as malaria and pathogenic bacteria of water destroyed by chlorination), veterinary health, or for non-agricultural surfaces (roads, airports, tracks, electrical networks…).

Summary

• 1 Etymology

• 2 History

• 3 Consumption

• 3.1 Agriculture

• 3.2 Weapon of war

• 4 Design of a pesticide

• 5 The other constituents : the formulation of a pesticide

• 6 Effects on the quality of the products

• 7 Effects on the environment

• 7.1 The dispersal of pesticides in soil

• 7.2 The effects on the environment

• 8 Effects on human health

• 8.1 Acute poisoning

• 8.2 Chronic poisoning

• 8.3 Prevention and control

• 9 Pesticide plants ?

• 10 Pesticide resistance in

• 10.1 Definition

• 10.2 Resistance to insecticides

• 10.3 Resistance factors

• 10.4 Strategy for limiting resistance

• 11 Residues

• 12 Labelling

• 13 Monitoring

Etymology

The word pesticide was created in French, on the model of the many words ending in the suffix - cide (Latin - cida, the verb latin caedo, caedere, «kill».), and on the basis of the word English pest (animal, insect or weed), which come from (as the french plague) pestis Latin which designated any kind of "curse"., calamity..

History

Chemical control has existed for thousands of years : the use of sulfur dates back to the ancient Greece (1000 BC) and arsenic is recommended by Pliny, Roman naturalist, as an insecticide. Plants known for their toxic properties have been used as pesticides (for example the pitted, in the middle ages, rodent). Treaties on these plants have been written (Ex : Treaty of poisons of Maimonides in 1135). Arsenical or lead-based (Lead arsenate) were used in the 16th century in China and Europe.

The insecticidal properties of tobacco were known as early as 1690. In India, gardeners used the roots of Derris and Lonchocarpus (rotenone) as an insecticide. Their use is widespread in Europe to 1900.

Inorganic chemistry developed in the 19th century, providing many pesticides mineral salts of copper-based. The fungicide copper sulfate-based spread, in particular the famous Bordeaux (mixture of sulphate of copper and lime) to combat the fungal invasions of the vine and potato, not without effects of pollution on soil (non-degradable copper). Mercury salts are used at the beginning of the 20th century for the treatment of seeds.

Chemical structure of an insecticide, DDT

Structural formula of atrazine, herbicide of the triazine family

Pesticides (Here the atrazine in the United States) subject use geographically and temporally targeted, What explains strong regional and seasonal variations in pollution of water and air by these products

The use and preparation of pesticides subject to regulations and precautions, due to their toxicity and sometimes the flammability of the solvent

The era of synthetic pesticides really began in the years 1930, taking advantage of the development of organic chemistry synthesis and research on chemical weapons during the first world war.

In 1874, Zeidler synthesises DDT (dichlorodiphenyltrichloroethane), including Müller in 1939 establishes the insecticidal properties. DDT is marketed as soon as 1943 and opens the way to the family of organochlorines. DDT has dominated the market until the beginning of the insecticides 1970.

In 1944, the 2,4-d herbicide, copied to a hormone of growth of plants and still strongly employee of our days, is synthesized.

World War II has generated, through the research undertaken to combat gas, the organophosphate family who, Since 1945, has seen a considerable yet to commence today development for some of these products, as malathion.

In 1950-1955 develops the United States family of substituted ureas herbicides (linuron, Diuron), followed shortly after by the Group quaternary ammonium and triazine herbicides.

Fungicides benzimidazole and deoxyribonucleosides type date from 1966, followed by fungicides imidazolic and fungicides so-called triazoliques IBS (inhibitors of the synthesis of sterols) which currently represent the largest market of fungicides.

In the years 1970-80 appears a new class of insecticides, pyrethroids which in turn dominate the insecticides.

Previously, Research of active substances was done randomly by submitting many biological tests products. When a product was selected for these qualities biocides, It sought to improve efficiency through the synthesis of analogues. This procedure has helped develop synthesis techniques that are today.

Now, emphasis is placed on the understanding of the modes of action and looking for new targets. Knowing the target, can then establish structure-activity relationships leading to the obtaining of active substances. This is possible thanks to the development of basic research in the fields of biology and chemistry and the new tools provided by quantum chemistry, Mathematics and computer science that allow modelling of these future molecules.

Currently, We are witnessing a consolidation of the market at the level of the families most recently discovered with new properties search. At the same time, new physiological targets of the animal or plant are explored with the aim of developing original modes of action products, products of biotechnology or chemical mediators.

Consumption

Since 1 July 2010 FAO was open free of charge to all (simple registration) its pesticide database in the FAOSTAT tool (the most comprehensive global database on food, agriculture and hunger).

Agriculture

The quantities of pesticides used in the world have been increasing regularly since 60 years. They appear to be decreasing in some countries in Europe, but to dose or equal weight, the active ingredients of today, are generally much more effective than those of earlier decades ; the France remains, in 2006, the second world consumer of pesticides, and third in 2007. Almost as much as the United States but with an agricultural area 10 times smaller.

Marketed molecules evolve, to circumvent resistance (insects, fungi or plants), to replace products banned because of their toxicity, or when interesting priori molecules come to replace other.

The most commonly used pesticides (in terms of quantity) are herbicides.

The molecule activates the best-selling as weed killer and most used in the world is glyphosate.

The France is (with the Netherlands) among those who consume the most of pesticides per hectare. In 2007 the France was threatened with a fine of 28 EUR million, by the European commission, for non-compliance of the European pesticide rules [4]The Grenelle of the environment (2007) asked to reduce from of 50% the amounts used, If possible before 2018. A reduction of 30% pesticides would be possible in France, with changes in practices important but without bouleveser production systems, According to a study “Ecophyto R&D”, commissioned by the Ministers in charge of Agriculture and the environment to a team coordinated by INRA, following the Grenelle of the environment. Nevertheless, According to IUPAP (Union des industries for the protection of plants), with 63.700 active material sold in the year t, the market has fallen by 19 % (volume in 2009). Manufacturers rely on price increase, less parasitic pressure, good climate conditions (including a cold spring) or the fall of revenues for the farmers of crops. The Grenelle II Act provides that "the Government shall forward annually to the Parliament and makes public a report on the monitoring of uses agricultural and non-agricultural pesticides in France., as well as the advances in agricultural research in this area.. This report will make a point annual dissemination of alternatives to pesticides to farmers, on the applied research and training, but also "the health of farmers and farm employees., and the results of epidemiological monitoring as defined in article 31 Act No. 2009-967 the 3 August 2009 programming relating to the implementation of the Grenelle of the environment. This report evaluates the health impact, environmental, of these uses social and economic. It clarifies the scope of each new plant protection products standard adopted in France under the rules and practices in the European Union".

Weapon of war

Agent orange is the nickname given to the most used herbicides used by the United States Army during the Vietnam war, in particular between 1961 and 1971.

Design of a pesticide

• A pesticide is composed of a set of molecules including :

• une (or more) active ingredient which is due, in whole or in part, the toxic effect.

• thinner that is a solid or a liquid (solvent) incorporated into a preparation and intended to lower the concentration of matter active. These are mostly vegetable oils in the case of liquids, clay or talc in the case of solids. The diluent is referred to as load in the latter case.

• of the Formulants that are devoid of biological activity substances, but likely to edit the pesticide qualities and ease of use.

There are worldwide almost 100 000 commercial specialties allowed for sale, composed from 900 different Active materials. 15 to 20 new active ingredients to add annually.

The properties of a pesticide are derived for the bulk of the structure of its active ingredient. It presents 3 Parties (This Division is artificial, No part cannot be literally separate) :

• a structure active, which ensures the pesticide power.

• chemical functions ensuring the more or less high solubility in water.

• support for the other two part conditional solubility in oil.

This notion of solubility is important because it is the affinity of a pesticide for water or fats that will condition its penetration into the target organism.

The other constituents : the formulation of a pesticide

The formulation of a pesticide aims to present the active material in a form which permits its application in him adding substances designed to improve and facilitate its action. These are adjuvants. They include the tensio-active, adhesives, some emulsifiers, stabilizers, antiperspirants, dyes, repellent materials, the Emetic (emetics) and sometimes antidotes.

• The formulation of a pesticide must meet 3 key objectives :

• ensure optimal efficiency in the active material : the active substance shall access under the best conditions to its biochemical target, i.e. achieve as quickly as possible with minimal loss. We thus limit its dispersion in the environment (ecological cost) and required hectare dosage (economic cost). For this purpose we improve contact with the Agency target by the addition of wetting agents (The 'wetting' are adjuvants that enhance the spread of the pesticide on the treated surface. They decrease the contact angle of droplets with plant support (or animal), with two consequences : a better adhesion and a greater surface contact and action. For systemic products, It seeks to improve the speed and balances penetration as well as the transport of goods in the plant. The formulation can also improve the biological effectiveness of the active molecule by synergy effects, additives that delay its degradation, thus prolonging its duration of action. Vice versa, other additives can accelerate its elimination by plants to protect or soil.

•
reduce the risk of poisoning for the manipulator : looking for a minimal contact and inhalation toxicity, by preventing the accidental ingestions by adding dye, repellent, antidote or spew (case of Paraquat in the Japan that is color blue and fitted with a spew). In the case of liquids, the less toxic solvents are selected. The dilution of the active material is even stronger that the latter is highly toxic.

• maximize the active material : the solvent used by the user is generally inexpensive and readily available. Various additives improve the conservation storage and/or avoid the corrosion of the equipment.

An international code of 2 uppercase letters, placed as a result of the trade name indicates the type of formulation. The main types of formulation are the following :

• Solid presentations :

• Wettable powders (WP) : the active material is finely ground (solid) or fixed (liquid) on an adsorbent media or porous (Silica). Surface-active agents (dodecylbenzene, lignosulfonate from Ca, Al or Na) and loads of dilution (kaolin, TALC, Chalk, silicate of aluminium and magnesium carbonate Ca) are added and antiredepositions agents, anti-static or defoamer. Stabilizers (antioxidants and buffer pH) are included for compatibility with other preparations. These powders should be dispersed in water at the time of employment.

• Pellets to disperse (WG) : granules obtained by the agglomeration with a little water of active ingredient, load binders and dispersing agents and, followed by a drying. These powders should be dispersed in water at the time of employment.

• The micro-granules (MG) : identical to the WG, but of a smaller size (0,1 to 0,6 mm).

• Liquid presentations :

• Soluble concentrate (SL) : It is a solution of active material to dilute with water, added surfactants.

• Concentrated suspensions (SC) : Active solids, insoluble in water are maintained in suspension in water, in the presence of wetting agents, dispersants, thickeners (bentonite, Silica) anti-redeposition agent or, antifreeze (ethylene glycol, urea) anti-foaming and sometimes of bactericides (formaldehyde or formalin). These preparations are diluted in water at the time of employment.

• The concentrated emulsifiable (EC) : the active ingredients are put in concentrated solution in an organic solvent and emulsifiers responsible for stabilizing the emulsions obtained at the time of employment by dilution in water.

• Concentrated emulsions (EW) : the active material is dissolved in an organic solvent. The solution of emulsifying agents are dispersed in a small amount of water. This presentation is less toxic and less flammable than emulsifiable concentrates.

Effects on the quality of the products

It is a debated question.

The manufacturers estimate that pesticides improve the quality of the products, including reducing the risk of development of certain bacteria or fungi toxin producing.

Pesticides, or their systematic use Detractors argue that :

1. number of these pathogens develop little by little resistance to pesticides, as microbes do face too used antibiotic;

2. residues of pesticides accumulated on and in plant or animal products could cause problems for health;

3. pesticide residues may pose problems for animals that consume the food industry waste;

4. soils that degrade through the action of pesticides eventually produce fruits and vegetables lower quality.

According to a study from the University of California, published in Chemistry & Industry (26 March 2007), researchers have compared the same Orchard Kiwi products at the same time, one in organic farming, and the other with pesticides. At harvest, the kiwis 'bio' contained significantly more vita¬mine C, more minerals and polyphenol (supposed organic compounds 'good for health '., because reducing the formation of free radicals). Researchers estimate that the untreated kiwis better develop their defence mechanisms ; being more stressed, they manufacture for example more antioxidants.

Effects on the environment

The dispersal of pesticides in soil

During treatment, more than 90 % quantities used of pesticides do not reach the targeted pest. The bulk of pesticides ends up in soil where they undergo dispersion phenomena. Environmental risks are great that these products are toxic, used on surfaces and at doses/frequencies and that they are persistent and mobile in soils.

The ground has mineral and organic elements and living organisms. In the soil, pesticides are subject to simultaneous action of the phenomena of transfer, downtime and degradation.

The phenomena of transfer

• Transfers to the ground surface concern that a small proportion of products applied (usually less than 5 %). They contribute to the pollution of surface waters when they are trained, the State dissolves or withheld on Earth particles themselves driven.

Transfers in the soil are the most important. They are trained by rain water and move according to the movement of the water. These trips vary greatly according to the moisture regime, the permeability of soils, the nature of the product. For example, in silty soil, Aldicarb is a highly mobile substance while lindane does not migrate(the use of Aldicarb limit was set at 31/12/07, and will be banned from use after this date, as well as lindane which has a ban since the 20/06/02 date of entry into force)

The phenomena of asset

• This phenomenon is due to adsorption, resulting from the attraction of molecules of matter active in the gas phase or in solution in the liquid phase of the ground by the surfaces of mineral and organic soil components. Many factors influence on the ability of adsorption of soil, related to the characteristics of the molecule, or soil (mineral and organic components, pH, amount of water). Similarly, the phenomena of desorption that corresponds to the release of the molecule in the ground (inverse phenomenon of adsorption).

Pesticides are quickly adsorbed by soil humic substances (mineral and organic colloids). An adsorbed molecule is no longer in solution in the liquid or gaseous phase. Being more available, its biological effects are removed ; It is more degraded by soil micro-organisms which increases its persistence. It is no longer driven by the water, What prevents pollution of the latter. Its desorption makes it all its biotoxiques capabilities. More strongly retained in general in clay or organic matter-rich soils.

The phenomena of degradation

• Soil is an ecosystem that has a very high detoxification capacity. Degradation of the active processes lead finally to obtain mineral molecules such as H2O, CO2, NH3

Degradation is mainly provided by the biological organisms of the soil microflora (bacteria, Actinomycetes, mushrooms, algae, yeast), It can reach 1 t matter dry per hectare. Its action is exercised primarily in the first centimetres of the soil. There are also physical or chemical degradation process, as the photodecomposition. These actions contribute to decrease the amount of active substance in the soil and thus reduce the risk of pollution. The kinetics of degradation of a given molecule is determined by estimating the persistence of the product. For this, It determines its half life, which is the length at the end of which its initial concentration in the soil has been reduced by half. This half life may vary with temperature, soil type, Sunshine, etc : Thus, DDT is of approximately 30 months in temperate and 3 to 9 months in a tropical climate.

Lindane, DDT and endrin are degraded in a few weeks in flooded soils paddy fields, In contrast to aldrin, dieldrin and chlordane.

Soils behave as an active filter ensuring the degradation of pesticides, and selective, because they are able to retain some of these products.

As an example, We will quote the case of the copper oxychloride which accumulates in the soil and which resulted in the sterilization of 50 000 HA of some soils of banana plantations in Costa Rica.

The effects on the environment

They are complex, immediate or deferred in space and in time, and vary depending on many factors, which in particular :

• The toxicity and ecotoxicity of the substance active, associated additives and surfactants, of their degradation products (sometimes more toxic than the parent molecule) and/or their metabolites ;

• A possible synergistic action with other pollutants or environmental or affected body ;

• Half-life of the active substance or metabolites (If the active substance is biodegradable or degradable) ;

• The exposure time and dose (chronic exposure to low dose, exposure to high doses in a short time) ;

• The relative sensitivity of organs, of the body, ecosystem exposed, at the time of exposure and time if the product or its effects are persistent ; A by doses showing no effect on adult acute, endocrine disruption effects can affect the reproduction of agronomically important species (earthworms, for example) ;

• The age of the body or the exposed body (the embryo, the fetus, the cells being multiplication are generally more vulnerable to the toxic).

Pesticides can be responsible for pollution from diffuse and chronic or acute and accidental, during their manufacture, transport, use or disposal of products at the end of life, gradients, unused or forbidden.

Pesticides, their degradation products, and their metabolites can contaminate all compartments of the environment;

• Air (outside, Interior), as such showed a study on 3 years by the Institut Pasteur de Lille, in the North of France from 586 swabs on 3 different sites (3 population/urbanization and agriculture intensity gradients).

• Water (salted, brackish, sweet, tablecloth, surface). Meteor waters (rain, snow, hail, mist, Dew are also affected),

• Sol. Some little degradable pesticides are strongly adsorbed on soils they can pollute permanently (Chlordecone, Paraquat for example).

Some persistent pesticides can, long after their use, persist and move from one compartment to another ; or passively (desorption, evaporation, erosion...) either actively through biological processes (metabolism, bioturbation, bioconcentration, etc.). This is the case for example of DDT found even decades after its ban in some areas, far from any source of direct pollution.

Are found as "residue." (parent molecule, products and by-products of degradation or metabolites) in our food and drinks. Laws or directives impose thresholds do not exceed, which in drinking water.

Effects on human health

Acute poisoning

The time between exposure to the product and the onset of the disorder is relatively short, a few hours to a few days, most often to connect the effect to the cause.

Organochlorine derivatives induce first of digestive disorders (vomiting, diarrhea) followed by neurological disorders (headache, Vertigo) accompanied by a large fatigue. These followed by convulsions and sometimes loss of consciousness. If the subject is treated in time, the evolution towards healing without after-effects occurs generally. Acute poisoning with this type of product is relatively rare, unless voluntary ingestion (suicide) or accidental (absorption by mistake, derives from cloud, Jet sprayer...).

Organophosphate and carbamate derivatives, by inhibiting cholinesterase, induce accumulation of acetylcholine in the body leading to an overactive nervous system and a cholinergic crisis. Clinical signs are digestive disorders with salivary hypersecretion, nausea, vomiting, abdominal cramps, profuse diarrhea. There is more breathing difficulties with airway hypersecretion, cough and shortness of breath. Cardiac disorders are tachycardia with hypertension and hypotension. Neuromuscular disorders result in frequent and quick of all muscles contractions, involuntary movements, cramps and General muscle paralysis. Death comes quickly by asphyxia or cardiac arrest. A specific antidote exists for this category of product : atropine sulfate which quickly neutralizes the toxic effects.

In adults, rodenticides anticoagulants based products cause usually step - unless massive absorption for suicidal purposes- disorders of coagulation, or hemorrhage. On the other hand, in childhood, severe bleeding may occur. They act by lowering the rate of prothrombin in the blood, necessary for the formation of a blood clot, causing internal bleeding. Symptoms appear after a few days for a high dose, After a few weeks for repeated shooting: blood in urine, nosebleed, gingival hemorrhage, blood in the stool, anemia, weakness. Death may occur in the 5 to 7 days following.

According to the agricultural social mutuality (MSA) and the GRECAN laboratory, of first MSA studies concluded in France only about 100 to 200 acute poisoning (skin irritations, digestive disorders, headaches) per year are attributed to pesticides.

Chronic poisoning

Dermatological damage : redness, itching with possibility of ulceration or cracking, hives are very commonly seen, regarding rather the parts of the body (arm, face). Number of products cause skin problems, including the responsible rotenones of severe lesions in the genital regions.

Neurological impairment : organochlorines are appear muscular fatigue, a decrease in tactile sensitivity. Organophosphates caused long-term headache, anxiety, irritability, depression and insomnia, allies sometimes hallucinatory trouble. Some cause paralysis, such as mercury or arsenic derivatives.

Disorders of the hematopoietic system : organochlorines can cause a decrease in the rate of red blood cells and white blood cells, with risk of leukemia.

Violations of the cardiovascular system : organochlorines develop phenomena of palpitation and disturbance of the heart rhythm.

Violations of the respiratory system : These violations are often in connection with the phenomena of irritation caused by a large number of pesticides, thus promoting secondary infections and be the cause of bronchitis, rhinitis and pharyngitis.

Violations of sexual functions : a nematicide (DBCP) has caused among employees of the factory where it is synthesized a large number of cases of infertility. Other substances appear to be involved in the growing deletion of spermatogenesis, either directly as reprotoxic or at low doses or via cocktails of products such as endocrine disruptor. In this case, the embryo can be affected, even by exposure to low doses (genital anomalies, and perhaps increased risk of certain cancers and deletion of spermatogenesis in the future adult).

Fetal risk : pesticides cross the placental barrier and have a teratogenic effect on the embryo. This is the case of DDT, malathion, some phthalimides (fungicide close to thalidomide). May occur premature births or abortions, as well as malformations of genitalia by the boy. It is recommended that pregnant women avoid contact with pesticides between the 23rd and 40th day of pregnancy, but some products have a long half-life in the body (Lindane, DDT, for example).

Fears of hormonal disturbances : Some pesticides behave as "hormonal lures.. At 100 % of 308 Spanish pregnant women, then giving birth to children found to be in good health between 2000 and 2002, least one type of pesticide was found in the placenta (which contained an average of 8, and up to 15, amongst 17 pesticides wanted, organochlorine, because being also of endocrine disrupters). The most common pesticides were in this study 1, 1-dichloro-2, 2 bis (p chlorophenyl)-ethylene (DDE) to 92,7 %, lindane in 74,8 % and endosulfan-diol to 62,1 % (Lindane is banned, but very persistent).

Neurodegenerative diseases : A study published in 2006 was found to increase the risk of Parkinson's disease following exposure to certain pesticides, including… Exposure to pesticides increases the risk of Parkinson's disease closely of 70 % : 5 % of people exposed to pesticides might develop the disease against 3 % for the general population. This disease is also more common in rural areas than in urban areas. There is nevertheless no epidemiological study incriminating a particular product in Parkinson's disease. In France, This disease is however in no array of disease professional but a recent case could make case law.

Cancers : The GRECAN highlighted one more small number of cancers in farmers than in the general population, but with an occurrence of some cancers (Prostate, testes, brain (gliomas)…). A study begun in 2005 is underway and the monitoring of 180 000 persons affiliated with the agricultural social mutuality (MSA). There are in the world some 30 studies that all show a rise in the risk of brain tumors. According to the INSERM there appears to be a relationship between testicular cancer and exposure to pesticides.

The study of Isabelle Baldi : A study concluded mid-2007 that the risk of brain tumor is more than doubled among farmers very exposed to pesticides (all types of combined tumors, the risk of gliomas is even tripled). People using pesticides on their indoor plants also have a risk more than doubled to develop a brain tumor. The study does not say whether a product or a family of pesticide would be more responsible than others, but the author notes that 80 % pesticides used by winemakers are fungicides.

Another study[18], involving the French male population, statistical links between pesticides used and developed lymphomas, and shows that the incidence of lymphomas is two to three times higher among farmers.

At the molecular level, a French study has demonstrated that there was a relationship between occupational exposure to pesticides and the acquisition of a chromosomal abnormality known to be one of the initial stages of some cancers.

Prevention and control

Farmers engaged in spraying are the most exposed to an impact people on their health. When spraying, It is commonly recommended to wear coveralls and gloves suitable for this pesticide, as well as a mask for protection during the preparation.

However, These combinations are little worn, because they have critical drawbacks : little adapted to the diversity of the tasks of the farmer, they are a source of discomfort, including thermal, promote sweating and the persistence of the impregnations. In some cases, even, holders of such a combination are more contaminated than those who do not wear. Finally, combinations, and especially the mask, require a few easy maintenance.

Furthermore, the use of a combination is likely to damage the image of the farm : neighbouring residents may feel threatened by the spreading, consumers can associate this outfit to a poor quality of production. This social risk constitutes an additional factor often discourage the spreader use this protection.

In tractors, the air-conditioned pressurised cabins, Although expensive, provide a complement to protection. They have however they also usability defects and do not constitute adequate protection.

To overcome these limitations, informal practices are implemented : The limitation of exposure is the first precaution. Often, the smell is an important marker of exposure to the hazard, Although all pesticides do not smell, and that a substance may be harmful below the threshold of sensitivity. Sensitive individuals, including pregnant women, can be away from areas known to be treated.

Concerning the protection of consumers and the controls ;

• In Europe, Physan program (Phyto-Sanitary Controls) includes :

– a data base which strengthens other bases. It includes data from the implementation of legislation relating to controls in the EU on crops, plant products, seeds and plant varieties, as well as pesticides.

– the European network of information on the plant protection systems (EUROPHYT), provides information on the health of plants;

– PEST (I, II, III, IV and V) – Physan Pesticides, on the notifications of pesticide residues by the European Commission and by competent or authorized by Member States authorities ;

– CAT (I and II) – Physan catalog, which updates the catalogues of seed products marketed freely;

– FEED (I and II) – Physan Feedingstuff (Physan compound feedingstuffs), focused on the use and marketing of additives for animal feed.

• In France, Since 2006, the French food safety agency (AFSSA) is responsible to test pesticides on the market, prior to their approval. Thus, Afssa has banned in 2001 the treatment of the vines to arsenic after the discovery of suspicious diseases.

Children are particularly vulnerable. According to a study published in 2008 by the EPA, many babies don't develop capacity to metabolize (degrade) pesticides that they absorbed during the 2 first years of their life, which particularly exposes. The EPA has banned two household pesticides in the USA (Diazinon and Chlorpyrifos), which led to a rapid decrease of these products and the exposure of these products in New York, where children are healthier since the prohibition of these products. In addition, per kg of body weight, as with most of the toxic, children breathe in and consume more (on average) adults.

Pesticide plants ?

Detailed article : Companionship (Botany).

Many plants naturally produce substances to protect themselves : Thus tobacco produces the nicotine insecticide, and pyrethrin Chrysanthemum. This logic was pushed further by the introduction of genetically modified plants that also produce, generally throughout their growth cycle, their own active substances (Thus Bt, an insecticidal protein produced by a bacterium, that is produced in the plant genetically modified root-level, stems, leaves and pollen, but not in the seed) fungicides or bactericides substances or. However, the question arises whether to classify these bodies artificially created among the pesticides.

Pesticide resistance in

Definition

Pesticide resistance is the result of a variety of organisms tolerant doses that kill the majority of normal bodies. The resistant individuals multiply in the absence of intraspecific competition and they become in a few generations the majority individuals of the population.

The resistance is defined by the who as 'appearance in a population of individuals possessing the Faculty of tolerate doses of toxic substances which would exercise a lethal effect on the majority of individuals component a normal population of the same species'.

It is the result of the selection, by a pesticide, mutants that have an enzyme or physiological equipment to survive lethal doses of the pesticide.

A pesticide is content to select resistance, but does not create.

Resistance to insecticides

Since the first case recorded (sea lice resistance from San Jose to the polysulfides in Illinois orchards in 1905) cases of resistance have increased exponentially : 5 case in 1928, 137 in 1960, 474 in 1980. In 1986, 590 animal and plant species were resistant : 447 species of insects or mites, a hundred of pathogens of plants, 41 species of weeds as well as nematodes and rodents.

Many cases of resistance to insecticides is admittedly anecdotal, What about a particular place. On the other hand, others are generalized to the whole world, as for the fly domestic Musca domestica resistant to organochlorines or Tribolium (earthworm flour) resistant to malathion and lindane. The mosquito Culex pipiens has developed resistance to organophosphates.

All families of insecticides can induce resistance in insects. Pyrethroids and juvenile hormone analogs did not escape the rule, with 6 cases of resistance to pyrethroids in 1976, exploding in 54 case in 1984.

On the other hand, taxonomic level, different insect orders express varied sensitivities. Diptera have the largest number of cases of resistance, followed by the Hemiptera (aphids and bugs). Beetles, Lepidoptera and mites each represent 15 % cases of resistance. On the other hand, Hymenoptera (bees, Wasps) seem to resist the development of resistance, probably for genetic reasons.

In 1984, We knew 17 species of insects and mites resistant to the 5 major groups of pesticides : Leptinotarsa decemlineata the Colorado potato beetle, Myzus persicae peach aphid, Plutella xylostella ringworm of Cruciferae, the bollworm, armyworms Spodoptera and Anopheles species.

Resistance is sometimes sought : This is the case for the predatory mite Phytoseiulus persimilis used against spider mites of the greenhouses.

The crops by the phenomena of resistance are cotton and fruit. Examples include the case of the whitefly Bemisia tabaci (Whitefly) in cotton crops of the plain of Gezira in Sudan in the early 1980 or the one in the far East and in South East Asia rice leafhopper. In particular, in Indonesia, the chemical control of Nilaparvata lugens proved impossible in the mid 1980, forcing the country to turn to a concept of integrated protection of rice in 1986.

Resistance factors

The factors favouring the emergence of resistance are classified in 3 groups :

• Genetic factors : frequency, number and dominance of resistance genes, expression and interaction of these genes, previous selection by other active substances, degree of integration of the resistant gene and the Adaptive value.

• Biological factors : generation time, offspring, monogamy or polygamy, parthenogenesis and behavioural factors (mobility, migration, polyphagia, refuge area).

• operational factors : chemical structure of the product and its relationship to earlier products, persistence of residues, dosage, threshold selection, stage selected, mode of application, selectivity of the product, alternative selection.

The first two types of factors are inherent in this case and cannot be-a priori- human-modified, who may intervene at the level of the third group.

It is possible to establish a hierarchy of the factors in the appearance of the phenomena of resistance. The most important are :

• the number of annual generation : the risk of development of resistance is greater than the length of the development cycle is short and the number of annual generations high. The emergence of resistance is therefore linked number of generations which have undergone continuous selection pressure.

• the mobility of the populations : the influx of migrants strongly decreases the frequency of resistance among the survivors of a treatment by diluting the resistance genes in the population.

• the dominance of resistance genes : resistance appear more quickly, interacting with the applied dose which will affect the expression of dominance : for a low dose, sensitive heterozygotes are destroyed but resistant heterozygotes will survive, resulting in a functional dominance of the gene resistant.

Strategy for limiting resistance

It should be noted that the increase of applied dose does that increase the selection pressure. Similarly, the multiplication of treatments leads only to eliminate sensitive migrants likely to dilute resistance genes. It is therefore necessary to play on the operational factors in seeking to minimize the selection pressure. For this purpose, It is necessary to :

• Select a sufficiently different insecticide from those used previously

• Respect the application rate

• The application should be localized in time and space

• Use synergistic products

• Diversify control methods.

Many plants have been genetically modified to be tolerant to a total weedkiller (glyphosate). They therefore contribute to generalize the use of this herbicide, at the risk of extending the resistances which are beginning to appear in some plants.

Residues

Pesticide residue content is regulated at European level (Regulation 396/2005 and its annexes : Regulation 178/2006, Regulation 149/2008 and amendments). These regulations cover both food (human consumption) and animal feed.

A multiannual programme for monitoring pesticide residues in plant foods by the European Commission is driven annually, based on the results of analysis more 30 000 samples from throughout the European Union.

The results are available on the website of DG Sanco (Directorate-General for health of consumers of the European Commission) : http://EC.europa.EU/food/FVO/specialreports/pesticides_index_en.htm for the year 2006, pesticide was detected in 49,5 % fruit, vegetables and cereals placed on the market of the EU, the highest level of contamination ever recorded , According to the report of the Commission in Brussels but only 4,5 % exceed the regulatory limits (report published in 2008).

In France, for the year 2004 the DGCCRF controls (Directorate for competition of the Ministry of finance) indicate :

• less 4 % fruits and vegetables tested in France having greater than the allowable maximum limit pesticide levels

• Cereals and cereal products are 2,4 % non-compliance on 330 samples; These non conformities are largely due to the use of pesticides in grain storage, and not to the use in the field.

• No non compliance has been detected on the orange juice and the fruit or vegetables for infant feeding products.

These results are to be inserted in a critical reflection on the economic circuits the manufacture and marketing of pesticides. Among others, the authors of the book Silent Spring (Rachel Carson, 1962) and Pesticides. The revelations about a french scandal (2007) denounced the bias of the commissions of the risk and damage assessments.

Labelling

Each product is matched with a licence for one or more specific uses which must be specified on the label. Hazard class must also appear on the label, represented by an international logo.

Labelling here in question is that of the pesticide container. When it comes to fruits and vegetables destined for human consumption, so far, no mention of pesticides used during the phases of growth and maturation is made available to the final consumer.

Monitoring

Trade data (sales, commands) specific and geo-referenced would be useful to epidemiologists and ecoepidemiologues, but they are considered confidential by the producers. Pesticides volatilized into the air, or transported by water and adsorbed onto soil particles are difficult to track. It measures only a part of the used molecules, and still less degradation products. Also, for data and comply with the Aarhus convention on access to environmental information, some countries build long-term monitoring structures, including the France with a french Observatory of pesticides pesticide residues Observatory (ORP) created by the French Agency of environment and occupational health safety (AFSSET) who is from 2007 started to put online a map of interactive France giving access to available data on the presence of pesticide residues in air, water, soils and certain foodstuffs. The Agency encourages the owners of data on pesticides to contribute voluntarily to update this tool.

Content submitted to the CC-BY-SA license 3.0. Source : Article Pesticide from Wikipedia in french (authors)