Pesticides are substances meant for attracting,
seducing, destroying, or mitigating any pest. They are a class of biocide. The most common
use of pesticides is as plant protection products, which in general protect plants from damaging
influences such as weeds, plant diseases or insects. This use of pesticides is so common
that the term pesticide is often treated as synonymous with plant protection product,
although it is in fact a broader term, as pesticides are also used for non-agricultural
purposes. The term pesticide includes all of the following: herbicide, insecticide,
insect growth regulator, nematicide, termiticide, molluscicide, piscicide, avicide, rodenticide,
predacide, bactericide, insect repellent, animal repellent, antimicrobial, fungicide,
disinfectant, and sanitizer. In general, a pesticide is a chemical or biological
agent that deters, incapacitates, kills, or otherwise discourages pests. Target pests
can include insects, plant pathogens, weeds, mollusks, birds, mammals, fish, nematodes,
and microbes that destroy property, cause nuisance, or spread disease, or are disease
vectors. Although pesticides have benefits, some also have drawbacks, such as potential
toxicity to humans and other desired species. According to the Stockholm Convention on Persistent
Organic Pollutants, 9 of the 12 most dangerous and persistent organic chemicals are pesticides. Definition
The Food and Agriculture Organization has defined pesticide as:
any substance or mixture of substances intended for preventing, destroying, or controlling
any pest, including vectors of human or animal disease, unwanted species of plants or animals,
causing harm during or otherwise interfering with the production, processing, storage,
transport, or marketing of food, agricultural commodities, wood and wood products or animal
feedstuffs, or substances that may be administered to animals for the control of insects, arachnids,
or other pests in or on their bodies. The term includes substances intended for use
as a plant growth regulator, defoliant, desiccant, or agent for thinning fruit or preventing
the premature fall of fruit. Also used as substances applied to crops either before
or after harvest to protect the commodity from deterioration during storage and transport.
Pesticides can be classified by target organism, chemical structure, although the distinction
can sometimes blur), and physical state). Biopesticides include microbial pesticides
and biochemical pesticides. Plant-derived pesticides, or “botanicals”, have been developing
quickly. These include the pyrethroids, rotenoids, nicotinoids, and a fourth group that includes
strychnine and scilliroside. Many pesticides can be grouped into chemical
families. Prominent insecticide families include organochlorines, organophosphates, and carbamates.
Organochlorine hydrocarbons could be separated into dichlorodiphenylethanes, cyclodiene compounds,
and other related compounds. They operate by disrupting the sodium/potassium balance
of the nerve fiber, forcing the nerve to transmit continuously. Their toxicities vary greatly,
but they have been phased out because of their persistence and potential to bioaccumulate.
Organophosphate and carbamates largely replaced organochlorines. Both operate through inhibiting
the enzyme acetylcholinesterase, allowing acetylcholine to transfer nerve impulses indefinitely
and causing a variety of symptoms such as weakness or paralysis. Organophosphates are
quite toxic to vertebrates, and have in some cases been replaced by less toxic carbamates.
Thiocarbamate and dithiocarbamates are subclasses of carbamates. Prominent families of herbicides
include phenoxy and benzoic acid herbicides, triazines, ureas, and Chloroacetanilides.
Phenoxy compounds tend to selectively kill broad-leaf weeds rather than grasses. The
phenoxy and benzoic acid herbicides function similar to plant growth hormones, and grow
cells without normal cell division, crushing the plant’s nutrient transport system. Triazines
interfere with photosynthesis. Many commonly used pesticides are not included in these
families, including glyphosate. Pesticides can be classified based upon their
biological mechanism function or application method. Most pesticides work by poisoning
pests. A systemic pesticide moves inside a plant following absorption by the plant. With
insecticides and most fungicides, this movement is usually upward and outward. Increased efficiency
may be a result. Systemic insecticides, which poison pollen and nectar in the flowers, may
kill bees and other needed pollinators. In 2009, the development of a new class of
fungicides called paldoxins was announced. These work by taking advantage of natural
defense chemicals released by plants called phytoalexins, which fungi then detoxify using
enzymes. The paldoxins inhibit the fungi’s detoxification enzymes. They are believed
to be safer and greener. Types
Pesticides are often referred to according to the type of pest they control. Pesticides
can also be considered as either biodegradable pesticides, which will be broken down by microbes
and other living beings into harmless compounds, or persistent pesticides, which may take months
or years before they are broken down: it was the persistence of DDT, for example, which
led to its accumulation in the food chain and its killing of birds of prey at the top
of the food chain. Another way to think about pesticides is to consider those that are chemical
pesticides or are derived from a common source or production method.
Some examples of chemically-related pesticides are:
Organophosphate pesticides Organophosphates affect the nervous system
by disrupting the enzyme that regulates acetylcholine, a neurotransmitter. Most organophosphates
are insecticides. They were developed during the early 19th century, but their effects
on insects, which are similar to their effects on humans, were discovered in 1932. Some are
very poisonous. However, they usually are not persistent in the environment.
Carbamate pesticides Carbamate pesticides affect the nervous system
by disrupting an enzyme that regulates acetylcholine, a neurotransmitter. The enzyme effects are
usually reversible. There are several subgroups within the carbamates.
Organochlorine insecticides They were commonly used in the past, but many
have been removed from the market due to their health and environmental effects and their
persistence. Pyrethroid pesticides
They were developed as a synthetic version of the naturally occurring pesticide pyrethrin,
which is found in chrysanthemums. They have been modified to increase their stability
in the environment. Some synthetic pyrethroids are toxic to the nervous system.
Sulfonylurea herbicides Includes nicosulfuron, triflusulfuron methyl,
and chlorsulfuron broad-spectrum herbicides that kill plants by inhibiting the enzyme
acetolactate synthase. In the 1960s, more than 1 kg/ha crop protection chemical was
typically applied, while sulfonylureates allow as little as 1% as much material to achieve
the same effect. Biopesticides
Biopesticides are certain types of pesticides derived from such natural materials as animals,
plants, bacteria, and certain minerals. For example, canola oil and baking soda have pesticidal
applications and are considered biopesticides. At the end of 2001, there were approximately
195 registered biopesticide active ingredients and 780 products. Biopesticides fall into
three major classes: Microbial pesticides consist of a microorganism
e.g., a bacterium, fungus, virus, or protozoan as the active ingredient. Microbial pesticides
can control many different kinds of pests, although each separate active ingredient is
relatively specific for its target pest. For example, there are fungi that control certain
weeds, and other fungi that kill specific insects.
The most widely used microbial pesticides are subspecies and strains of Bacillus thuringiensis,
or Bt. Each strain of this bacterium produces a different mix of proteins, and specifically
kills one or a few related species of insect larvae. While some Bt’s control moth larvae
found on plants, other Bt’s are specific for larvae of flies and mosquitoes. The target
insect species are determined by whether the particular Bt produces a protein that can
bind to a larval gut receptor, thereby causing the insect larvae to starve.
Plant-Incorporated-Protectants are pesticidal substances that plants produce from genetic
material that has been added to the plant. For example, scientists can take the gene
for the Bt pesticidal protein, and introduce the gene into the plant’s own genetic material.
Then the plant, instead of the Bt bacterium, manufactures the substance that destroys the
pest. The protein and its genetic material, but not the plant itself, are regulated by
EPA. Biochemical pesticides are naturally occurring
substances that control pests by non-toxic mechanisms. Conventional pesticides, by contrast,
are, in general, synthetic materials that directly kill or inactivate the pest. Biochemical
pesticides include substances, such as insect sex pheromones, that interfere with mating,
as well as various scented plant extracts that attract insect pests to traps. Because
it is sometimes difficult to determine whether a substance meets the criteria for classification
as a biochemical pesticide, EPA has established a special committee to make such decisions.
Classified by type of pest Pesticides that are related to the type of
pests are: Further types of pesticides
The term pesticide also include these substances: Defoliants : Cause leaves or other foliage
to drop from a plant, usually to facilitate harvest.Desiccants : Promote drying of living
tissues, such as unwanted plant tops.Insect growth regulators : Disrupt the molting,
maturity from pupal stage to adult, or other life processes of insects.Plant growth regulators :
Substances that alter the expected growth, flowering, or reproduction rate of plants.
Uses Pesticides are used to control organisms that
are considered to be harmful. For example, they are used to kill mosquitoes that can
transmit potentially deadly diseases like West Nile virus, yellow fever, and malaria.
They can also kill bees, wasps or ants that can cause allergic reactions. Insecticides
can protect animals from illnesses that can be caused by parasites such as fleas. Pesticides
can prevent sickness in humans that could be caused by moldy food or diseased produce.
Herbicides can be used to clear roadside weeds, trees and brush. They can also kill invasive
weeds that may cause environmental damage. Herbicides are commonly applied in ponds and
lakes to control algae and plants such as water grasses that can interfere with activities
like swimming and fishing and cause the water to look or smell unpleasant. Uncontrolled
pests such as termites and mould can damage structures such as houses. Pesticides are
used in grocery stores and food storage facilities to manage rodents and insects that infest
food such as grain. Each use of a pesticide carries some associated risk. Proper pesticide
use decreases these associated risks to a level deemed acceptable by pesticide regulatory
agencies such as the United States Environmental Protection Agency and the Pest Management
Regulatory Agency of Canada. Pesticides can save farmers’ money by preventing
crop losses to insects and other pests; in the U.S., farmers get an estimated fourfold
return on money they spend on pesticides. One study found that not using pesticides
reduced crop yields by about 10%. Another study, conducted in 1999, found that a ban
on pesticides in the United States may result in a rise of food prices, loss of jobs, and
an increase in world hunger. DDT, sprayed on the walls of houses, is an
organochloride that has been used to fight malaria since the 1950s. Recent policy statements
by the World Health Organization have given stronger support to this approach. Dr. Arata
Kochi, WHO’s malaria chief, said, “One of the best tools we have against malaria is
indoor residual house spraying. Of the dozen insecticides WHO has approved as safe for
house spraying, the most effective is DDT.” However a later October 2007 study linked
breast cancer from exposure to DDT prior to puberty. Poisoning may also occur due to use
of DDT and other chlorinated hydrocarbons by entering the human food chain when animal
tissues are affected. Symptoms include nervous excitement, tremors, convulsions, or death.
Scientists estimate that DDT and other chemicals in the organophosphate class of pesticides
have saved 7 million human lives since 1945 by preventing the transmission of diseases
such as malaria, bubonic plague, sleeping sickness, and typhus. However, DDT use is
not always effective, as resistance to DDT was identified in Africa as early as 1955,
and by 1972 nineteen species of mosquito worldwide were resistant to DDT. A study for the World
Health Organization in 2000 from Vietnam established that non-DDT malaria controls were significantly
more effective than DDT use. The ecological effect of DDT on organisms is an example of
bioaccumulation. Manufacturing Process of Pesticides
Quantity and variety In 2006 and 2007, the world used approximately
5.2 billion pounds of pesticides, with herbicides constituting the biggest part of the world
pesticide use at 40%, followed by insecticides and fungicides. In 2006 and 2007 the U.S.
used approximately 1.1 billion pounds of pesticides, accounting for 22% of the world total, including
857 million pounds of conventional pesticides, which are used in the agricultural sector
as well as the industrial, commercial, governmental and home & garden sectors.Pesticides are also
found in majority of U.S. households with 78 million out of the 105.5 million households
indicating that they use some form of pesticide. As of 2007, there were more than 1,055 active
ingredients registered as pesticides, which yield over 20,000 pesticide products that
are marketed in the United States. The US used some 2.2 pounds per hactare of
arable land compared with 10.3 in China, 3.0 in the UK, .2 in Cameroun, 13.1 in Japan and
5.6 in Italy. Insecticide use in the US has declined by more than half since 1980, mostly
due to the near phase-out of organophosphates. In corn fields, the decline was even steeper,
due to the switchover to transgenic Bt corn. For the global market of crop protection products,
market analysts forecast revenues of over 52 billion US$ in 2019.
Costs On the cost side of pesticide use there can
be costs to the environment, costs to human health, as well as costs of the development
and research of new pesticides. Health effects Pesticides may cause acute and delayed health
effects in workers who are exposed. Pesticide exposure can cause a variety of adverse health
effects, ranging from simple irritation of the skin and eyes to more severe effects such
as affecting the nervous system, mimicking hormones causing reproductive problems, and
also causing cancer. A 2007 systematic review found that “most studies on non-Hodgkin lymphoma
and leukemia showed positive associations with pesticide exposure” and thus concluded
that cosmetic use of pesticides should be decreased. Strong evidence also exists for
other negative outcomes from pesticide exposure including neurological, birth defects, fetal
death, and neurodevelopmental disorder. The American Medical Association recommends
limiting exposure to pesticides and using safer alternatives: “Particular uncertainty
exists regarding the long-term effects of low-dose pesticide exposures.”
Though the U.S. Environmental Protection Agency limits the amount of each pesticide that may
be present on a food item, there exists no limit to the number of different chemicals
that can be used. This leads to a possibly even more dangerous effect known as a “chemical
cocktail”. The chemicals may form one of many dangerous interactions and have an unmeasured
synergistic effect. The World Health Organization and the UN Environment
Programme estimate that each year, 3 million workers in agriculture in the developing world
experience severe poisoning from pesticides, about 18,000 of whom die. According to one
study, as many as 25 million workers in developing countries may suffer mild pesticide poisoning
yearly. One study found pesticide self-poisoning the
method of choice in one third of suicides worldwide, and recommended, among other things,
more restrictions on the types of pesticides that are most harmful to humans.
A 2007 study by the California Department of Public Health found that women in the first
eight weeks of pregnancy who live near farm fields sprayed with the organochlorine pesticides
dicofol and endosulfan are several times more likely to give birth to children with autism.
Environmental effect Pesticide use raises a number of environmental
concerns. Over 98% of sprayed insecticides and 95% of herbicides reach a destination
other than their target species, including non-target species, air, water and soil. Pesticide
drift occurs when pesticides suspended in the air as particles are carried by wind to
other areas, potentially contaminating them. Pesticides are one of the causes of water
pollution, and some pesticides are persistent organic pollutants and contribute to soil
contamination. In addition, pesticide use reduces biodiversity,
reduces nitrogen fixation, contributes to pollinator decline, destroys habitat, and
threatens endangered species. Pests can develop a resistance to the pesticide,
necessitating a new pesticide. Alternatively a greater dose of the pesticide can be used
to counteract the resistance, although this will cause a worsening of the ambient pollution
problem. Since chlorinated hydrocarbon pesticides dissolve
in fats and are not excreted, organisms tend to retain them almost indefinitely. Biological
magnification is the process whereby these chlorinated hydrocarbons are more concentrated
at each level of the food chain. Among marine animals, pesticide concentrations are higher
in carnivorous fishes, and even more so in the fish-eating birds and mammals at the top
of the ecological pyramid. Global distillation is the process whereby pesticides are transported
from warmer to colder regions of the Earth, in particular the Poles and mountain tops.
Pesticides that evaporate into the atmosphere at relatively high temperature can be carried
considerable distances by the wind to an area of lower temperature, where they condense
and are carried back to the ground in rain or snow.
In order to reduce negative impacts, it is desirable that pesticides be degradable or
at least quickly deactivated in the environment. Such loss of activity or toxicity of pesticides
is due to both innate chemical properties of the compounds and environmental processes
or conditions. For example, the presence of halogens within a chemical structure often
slows down degradation in an aerobic environment. Adsorption to soil may retard pesticide movement,
but also may reduce bioavailability to microbial degraders.
Economics Human health and environmental cost from pesticides
in the United States is estimated at $9.6 billion:
Additional costs include the registration process and the cost of purchasing pesticides.
The registration process can take several years to complete and can cost $50–70 million
for a single pesticide. Annually the United States spends $10 billion on pesticides.
Benefits There are two levels of benefits for pesticide
use, primary and secondary. Primary benefits are direct gains from the use of pesticides
and secondary benefits are effects that are more long-term.
Primary benefits 1. Controlling pests and plant disease vectors
Improved crop/livestock yields Improved crop/livestock quality
Invasive species controlled 2. Controlling human/livestock disease vectors
and nuisance organisms Human lives saved and suffering reduced
Animal lives saved and suffering reduced Diseases contained geographically
3. Controlling organisms that harm other human activities and structures
Drivers view unobstructed Treeleaf hazards prevented
Wooden structures protected Monetary
Every dollar that is spent on pesticides for crops yields four dollars in crops saved.
This means based that, on the amount of money spent per year on pesticides, $10 billion,
there is an additional $40 billion savings in crop that would be lost due to damage by
insects and weeds. In general, farmers benefit from having an increase in crop yield and
from being able to grow a variety of crops throughout the year. Consumers of agricultural
products also benefit from being able to afford the vast quantities of produce available year-round.
The general public also benefits from the use of pesticides for the control of insect-borne
diseases and illnesses, such as malaria. The use of pesticides creates a large job market,
which provides jobs for all of the people working within the industry.
Alternatives Alternatives to pesticides are available and
include methods of cultivation, use of biological pest controls, genetic engineering, and methods
of interfering with insect breeding. Application of composted yard waste has also been used
as a way of controlling pests. These methods are becoming increasingly popular and often
are safer than traditional chemical pesticides. In addition, EPA is registering reduced-risk
conventional pesticides in increasing numbers. Cultivation practices include polyculture,
crop rotation, planting crops in areas where the pests that damage them do not live, timing
planting according to when pests will be least problematic, and use of trap crops that attract
pests away from the real crop. In the U.S., farmers have had success controlling insects
by spraying with hot water at a cost that is about the same as pesticide spraying.
Release of other organisms that fight the pest is another example of an alternative
to pesticide use. These organisms can include natural predators or parasites of the pests.
Biological pesticides based on entomopathogenic fungi, bacteria and viruses cause disease
in the pest species can also be used. Interfering with insects’ reproduction can
be accomplished by sterilizing males of the target species and releasing them, so that
they mate with females but do not produce offspring. This technique was first used on
the screwworm fly in 1958 and has since been used with the medfly, the tsetse fly, and
the gypsy moth. However, this can be a costly, time consuming approach that only works on
some types of insects. Another alternative to pesticides is the thermal
treatment of soil through steam. Soil steaming kills pest and increases soil health.
In India, traditional pest control methods include using Panchakavya, the “mixture of
five products.” The method has recently experienced a resurgence in popularity due in part to
use by the organic farming community. Agroecology emphasize nutrient recycling,
use of locally available and renewable resources, adaptation to local conditions, utilization
of microenvironments, reliance on indigenous knowledge and yield maximization while maintaining
soil productivity. Agroecology also emphasizes empowering people and local communities to
contribute to development, and encouraging “multi-directional” communications rather
than the conventional “top-down” method. Push pull strategy The term “push-pull” was established in 1987
as an approach for integrated pest management. This strategy uses a mixture of behavior-modifying
stimuli to manipulate the distribution and abundance of insects. “Push” means the insects
are repelled or deterred away from whatever resource that is being protected. “Pull” means
that certain stimuli are used to attract pests to trap crops where they will be killed. There
are numerous different components involved in order to implement a Push-Pull Strategy
in IPM. Many case studies testing the effectiveness
of the push-pull approach have been done across the world. The most successful push-pull strategy
was developed in Africa for subsistence farming. Another successful case study was performed
on the control of Helicoverpa in cotton crops in Australia. In Europe, the Middle East,
and the United States, push-pull strategies were successfully used in the controlling
of Sitona lineatus in bean fields. Some advantages of using the push-pull method
are less use of chemical or biological materials and better protection against insect habituation
to this control method. Some disadvantages of the push-pull strategy is that if there
is a lack of appropriate knowledge of behavioral and chemical ecology of the host-pest interactions
then this method becomes unreliable. Furthermore, because the push-pull method is not a very
popular method of IPM operational and registration costs are higher.
Effectiveness Some evidence shows that alternatives to pesticides
can be equally effective as the use of chemicals. For example, Sweden has halved its use of
pesticides with hardly any reduction in crops. In Indonesia, farmers have reduced pesticide
use on rice fields by 65% and experienced a 15% crop increase. A study of Maize fields
in northern Florida found that the application of composted yard waste with high carbon to
nitrogen ratio to agricultural fields was highly effective at reducing the population
of plant-parasitic nematodes and increasing crop yield, with yield increases ranging from
10% to 212%; the observed effects were long-term, often not appearing until the third season
of the study. However, pesticide resistance is increasing.
In the 1940s, U.S. farmers lost only 7% of their crops to pests. Since the 1980s, loss
has increased to 13%, even though more pesticides are being used. Between 500 and 1,000 insect
and weed species have developed pesticide resistance since 1945.
Regulation International
In most countries, pesticides must be approved for sale and use by a government agency.
In Europe, recent EU legislation has been approved banning the use of highly toxic pesticides
including those that are carcinogenic, mutagenic or toxic to reproduction, those that are endocrine-disrupting,
and those that are persistent, bioaccumulative and toxic or very persistent and very bioaccumulative.
Measures were approved to improve the general safety of pesticides across all EU member
states. Though pesticide regulations differ from country
to country, pesticides, and products on which they were used are traded across international
borders. To deal with inconsistencies in regulations among countries, delegates to a conference
of the United Nations Food and Agriculture Organization adopted an International Code
of Conduct on the Distribution and Use of Pesticides in 1985 to create voluntary standards
of pesticide regulation for different countries. The Code was updated in 1998 and 2002. The
FAO claims that the code has raised awareness about pesticide hazards and decreased the
number of countries without restrictions on pesticide use.
Three other efforts to improve regulation of international pesticide trade are the United
Nations London Guidelines for the Exchange of Information on Chemicals in International
Trade and the United Nations Codex Alimentarius Commission. The former seeks to implement
procedures for ensuring that prior informed consent exists between countries buying and
selling pesticides, while the latter seeks to create uniform standards for maximum levels
of pesticide residues among participating countries. Both initiatives operate on a voluntary
basis. Pesticide safety education and pesticide applicator
regulation are designed to protect the public from pesticide misuse, but do not eliminate
all misuse. Reducing the use of pesticides and choosing less toxic pesticides may reduce
risks placed on society and the environment from pesticide use. Integrated pest management,
the use of multiple approaches to control pests, is becoming widespread and has been
used with success in countries such as Indonesia, China, Bangladesh, the U.S., Australia, and
Mexico. IPM attempts to recognize the more widespread impacts of an action on an ecosystem,
so that natural balances are not upset. New pesticides are being developed, including
biological and botanical derivatives and alternatives that are thought to reduce health and environmental
risks. In addition, applicators are being encouraged to consider alternative controls
and adopt methods that reduce the use of chemical pesticides.
Pesticides can be created that are targeted to a specific pest’s lifecycle, which can
be environmentally more friendly. For example, potato cyst nematodes emerge from their protective
cysts in response to a chemical excreted by potatoes; they feed on the potatoes and damage
the crop. A similar chemical can be applied to fields early, before the potatoes are planted,
causing the nematodes to emerge early and starve in the absence of potatoes.
United States In the United States, the Environmental Protection
Agency is responsible for regulating pesticides under the Federal Insecticide, Fungicide,
and Rodenticide Act and the Food Quality Protection Act. Studies must be conducted to establish
the conditions in which the material is safe to use and the effectiveness against the intended
pest(s). The EPA regulates pesticides to ensure that these products do not pose adverse effects
to humans or the environment. Pesticides produced before November 1984 continue to be reassessed
in order to meet the current scientific and regulatory standards. All registered pesticides
are reviewed every 15 years to ensure they meet the proper standards. During the registration
process, a label is created. The label contains directions for proper use of the material
in addition to safety restrictions. Based on acute toxicity, pesticides are assigned
to a Toxicity Class. Some pesticides are considered too hazardous
for sale to the general public and are designated restricted use pesticides. Only certified
applicators, who have passed an exam, may purchase or supervise the application of restricted
use pesticides. Records of sales and use are required to be maintained and may be audited
by government agencies charged with the enforcement of pesticide regulations. These records must
be made available to employees and state or territorial environmental regulatory agencies.
The EPA regulates pesticides under two main acts, both of which amended by the Food Quality
Protection Act of 1996. In addition to the EPA, the United States Department of Agriculture
and the United States Food and Drug Administration set standards for the level of pesticide residue
that is allowed on or in crops. The EPA looks at what the potential human health and environmental
effects might be associated with the use of the pesticide.
In addition, the U.S. EPA uses the National Research Council’s four-step process for human
health risk assessment: Hazard Identification, Dose-Response Assessment, Exposure Assessment,
and Risk Characterization. Recently Kaua’i County passed Bill No. 2491
to add an article to Chapter 22 of the county’s code relating to pesticides and GMOs. The
bill strengthens protections of local communities in Kaua’i where many large pesticide companies
test their products. History
Since before 2000 BC, humans have utilized pesticides to protect their crops. The first
known pesticide was elemental sulfur dusting used in ancient Sumer about 4,500 years ago
in ancient Mesopotamia. The Rig Veda, which is about 4,000 years old, mentions the use
of poisonous plants for pest control. By the 15th century, toxic chemicals such as arsenic,
mercury, and lead were being applied to crops to kill pests. In the 17th century, nicotine
sulfate was extracted from tobacco leaves for use as an insecticide. The 19th century
saw the introduction of two more natural pesticides, pyrethrum, which is derived from chrysanthemums,
and rotenone, which is derived from the roots of tropical vegetables. Until the 1950s, arsenic-based
pesticides were dominant. Paul Müller discovered that DDT was a very effective insecticide.
Organochlorines such as DDT were dominant, but they were replaced in the U.S. by organophosphates
and carbamates by 1975. Since then, pyrethrin compounds have become the dominant insecticide.
Herbicides became common in the 1960s, led by “triazine and other nitrogen-based compounds,
carboxylic acids such as 2,4-dichlorophenoxyacetic acid, and glyphosate”.
The first legislation providing federal authority for regulating pesticides was enacted in 1910;
however, decades later during the 1940s manufacturers began to produce large amounts of synthetic
pesticides and their use became widespread. Some sources consider the 1940s and 1950s
to have been the start of the “pesticide era.” Although the U.S. Environmental Protection
Agency was established in 1970 and amendments to the pesticide law in 1972, pesticide use
has increased 50-fold since 1950 and 2.3 million tonnes of industrial pesticides are now used
each year. Seventy-five percent of all pesticides in the world are used in developed countries,
but use in developing countries is increasing. In 2001 the EPA stopped reporting yearly pesticide
use statistics. A study of USA pesticide use trends through 1997 was published in 2003
by the National Science Foundation’s Center for Integrated Pest Management.
In the 1960s, it was discovered that DDT was preventing many fish-eating birds from reproducing,
which was a serious threat to biodiversity. Rachel Carson wrote the best-selling book
Silent Spring about biological magnification. The agricultural use of DDT is now banned
under the Stockholm Convention on Persistent Organic Pollutants, but it is still used in
some developing nations to prevent malaria and other tropical diseases by spraying on
interior walls to kill or repel mosquitoes. See also Index of pesticide articles
Pesticide residue Pest control
References Further reading
Books Greene, Stanley A.; Pohanish, Richard P..
Sittig’s Handbook of Pesticides and Agricultural Chemicals. SciTech Publishing, Inc. ISBN 0-8155-1516-2. 
Tomlin, Clive. “The Pesticide Manual”, 14th edition, 1350 pages. British Crop Protection
Council. ISBN 1-901396-14-2.  Hamilton, Denis; Crossley, Stephen. Pesticide
residues in food and drinking water. J. Wiley. ISBN 0-471-48991-3. 
Hond, Frank et al.. Pesticides: problems, improvements, alternatives. Blackwell Science.
ISBN 0-632-05659-2.  Kegley, Susan E.; Wise, Laura J.. Pesticides
in fruits and vegetables. University Science Books. ISBN 0-935702-46-6. 
Larramendy, Marcelo L.; Soloneski, Sonia [Editors](2014): Pesticides: Toxic Aspects. InTech. ISBN 978-953-51-1217-4
[Open Access Download available] Levine, Marvin J.. Pesticides: A Toxic Time
Bomb in our Midst. Praeger Publishers. ISBN 978-0-275-99127-2.  Ware, George W.; Whitacre, David M.. Pesticide
Book. Meister Publishing Co. ISBN 1-892829-11-8.  Watson, David H.. Pesticide, veterinary and
other residues in food. Woodhead Publishing. ISBN 1-85573-734-5.  Journal articles
Alarcon WA, Calvert GM, Blondell JM, Mehler LN, Sievert J, Propeck M, Tibbetts DS, Becker
A, Lackovic M, Soileau SB, Das R, Beckman J, Male DP, Thomsen CL, Stanbury M. “Acute
Illnesses Associated With Pesticide Exposure at Schools”. Journal of the American Medical
Association 294: 455–465. doi:10.1001/jama.294.4.455. PMID 16046652. 
World Health Organization Persistent Organic Pollutants: Impact on Child Health
News Janofsky, M. “E.P.A. recommends limits on
thousands of uses of pesticides”. New York Times. Retrieved 2006-08-24. 
Janofsky, M. “Unions say E.P.A. bends to political pressure”. New York Times. Retrieved 2007-10-10. 
External links National Pesticide Information Center Information
about pesticide-related topics. Pesticide Modes of action
Beyond Pesticides, founded in 1981 as the National Coalition Against the Misuse of Pesticides
– Source of information on pesticide hazards, least-toxic practices and products, and on
pesticide issues. Website has Daily News Blog relating to pesticides.
Compendium of Pesticide Common Names: Classified Lists of Pesticides Lists of pesticide names
by type. Pesticide Action Network. PAN Pesticides Database.
Compilation of multiple regulatory databases into a web-accessible form.
PPDB Pesticide Properties Database A to Z index of pesticides
Pesticide regulatory authorities UK Pesticides Safety Directorate
Pesticide laws guidance for Scotland and Northern Ireland on
European Commission pesticide information United States Environmental Protection Agency
Office of Pesticides Program US EPA Pesticide Chemical Search
USDA Pesticide Data Program, tracking residue levels in food
Human health NIH encyclopedia pages with emergency treatment
of Insecticide exposure Hazard Communications for Agricultural Workers
National Agricultural Workers Survey David Suzuki Foundation: Protecting Your Health
from Pesticides Field evaluation of protective clothing against
non-agricultural pesticides by A Soutar and others. Institute of Occupational Medicine
Research Report TM04 A comparison of different methods for assessment
of dermal exposure to nonagricultural pesticides in three sectors by SN Tannahill and others.
Institute of Occupational Medicine Research Report TM07