Biological Sciences
Types of Pesticides
Pesticides are chemicals used to control pests and increase crop yield. They can be categorized into three main types: herbicides (targeting weeds), insecticides (targeting insects), and fungicides (targeting fungi). Each type of pesticide has specific modes of action and targets, and their use requires careful consideration of potential environmental and health impacts.
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12 Key excerpts on "Types of Pesticides"
eBook - ePubEnvironmental Forensics
Contaminant Specific Guide
- Robert D. Morrison, Brian L. Murphy(Authors)
- 2010(Publication Date)
- Academic Press(Publisher)
8Pesticides
Randy D. Horsak, Philip B. Bedient, M. Coreen Hamilton and F. Ben ThomasPublisher Summary
The purpose of this chapter is to provide a brief overview of the Types of Pesticides, their fate in their environment, analytical considerations and forensic techniques available to age date and identify the source of the pesticide release into the environment. A pesticide is defined as a chemical agent used to destroy or control pests. The generic term pesticides can apply to a wide spectrum of chemicals, including insecticides, rodenticides, herbicides, fungicides, biocides, and similar chemicals. Pesticides are extensively investigated and their chemical properties, toxicological properties, and fate and transport are well known. Pesticides may be categorized according to a number of parameters, including chemical structure, route of exposure, and method of application. Pesticides include herbicides, insecticides, fungicides, rodenticides, fumigants, and other categories. Typically, the most widely used pesticides in commercial applications are insecticides, herbicides, and fungicides, while more rodenticides and botanicals are used in domestic applications.Contents8.1. INTRODUCTION8.2. Types of Pesticides8.3. PHYSICAL AND CHEMICAL PROPERTIES8.4. ANALYTICAL TESTING8.5. FORENSIC TECHNIQUES8.6. CASE STUDIESREFERENCES8.1 INTRODUCTION
A pesticide is defined as a chemical agent used to destroy or control pests. The root word is the Latin word “cida” which means to kill. The generic term “pesticides” can apply to a wide spectrum of chemicals, including insecticides, rodenticides, herbicides, fungicides, biocides, and similar chemicals.Pesticides have been extensively investigated since the 1960s, and their chemical properties, toxicological properties, and fate and transport are well known. The purpose of this chapter is to provide a brief overview of the Types of Pesticides, their fate in their environment, analytical considerations and forensic techniques available to age date and identify the source of the pesticide release into the environment.
- L. DeVere Burton(Author)
- 2018(Publication Date)
- Cengage Learning EMEA(Publisher)
The organic chem-istry involved in pesticide production is often complex and extremely diverse. However, a classification system for pesticides that is based on the type of pest to be treated is useful (Figure 14-2). The major pesticide groups are herbicides, insecticides, and fungicides. In the United States, the amount of pesticide used each year totals 5.1 billion pounds (U.S. EPA, January 2012). Currently, the EPA has registered more than 600 chemicals that are formulated into some 30,000 products for pest control. Of the three major pesticide categories, the largest volume was for herbicides, followed by insecticides and fungicides. TERMS TO KNOW element compound inorganic compound organic compound contact herbicide systemic herbicide phloem preemergence herbicide postemergence herbicide photodecomposition insecticide protectant fungicide eradicant fungicide formulation signal word symbol LD 50 LC 50 toxicity acute toxicity chronic toxicity carcinogen INTERNET KEY WORDS: inorganic pesticide organic pesticide INTERNET KEY WORDS: insecticide fungicide pesticide use 294 SECTION 4 INTEGRATED PEST MANAGEMENT HERBICIDES Herbicides are grouped into several major categories based on application method, type of control, and chemical structure. The terminology for herbicide use, type of control, and chemical family follows. Selective Herbicides A selective herbicide kills or affects only a certain type or group of plants. The selectivity of an herbicide can be caused by many different factors. Some of these factors include: ■ differences in herbicide chemistry, formulation, and concentration; ■ differences in plant age, morphology, growth rate, and plant physiology; and ■ environmental differences such as temperature, rainfall, and soil type. Nonselective Herbicides A nonselective herbicide controls or kills all plants. These herbicides are used for many different purposes.
eBook - PDFEnvironmental Ecology
The Impacts of Pollution and Other Stresses on Ecosystem Structure and Function
- Bill Freedman(Author)
- 2013(Publication Date)
- Academic Press(Publisher)
This chapter describes some of the ecological impacts of the use of pesticides. The most promi-nent uses of pesticides are considered first, and then the characteristics of selected groups of these chemicals are described. This is followed by a con-sideration of some notable examples of the detri-mental effects of pesticides on nontarget, offsite wildlife, especially birds. Then, to give an appre-ciation of the ecological impacts of large-scale pesticide spraying in a complex natural ecosystem, several case studies are examined. The first case deals with the extensive spraying of conifer forest infested with spruce budworm. The second case examines the use of herbicides to manipulate plant regeneration on forestry clear-cuts. 8.2 CLASSIFICATION OF PESTICIDES BY THEIR USE AND CHEMICAL CHARACTERISTICS Pesticides comprise a diverse group of chemicals, which can be classified according to (1) the pest organisms against which they are targetted, (2) the use sector, such as in agriculture, around the home, or in forestry, and (3) their similarity of chemical structure. Classification of Pesticides by Their Biological Target First, a classification of pesticides based on their intended pest target will be considered, with some prominent examples of each group [after Metcalf, 1971; Eto, 1974; McEwen and Stephenson, 1979; Entomological Society of America (ESA), 1980]. 1. Fungicides are used to protect crop plants and animals from fungal pathogens. Fungi-cides include (a) inorganic chemicals such as elemental sulfur, and copper compounds such as Bordeaux mixture (pp. 186-189 give a more detailed description of these and other pesticides used as examples in this section); (b) organometallic compounds of mercury and tin; (c) chlorophenolics such as tri-, tetra-, and pentachlorophenol; (d) antibiotics such as penicillin and strep-tomycin; and (e) synthetic organics such as the dithiocarbamates and captans.
eBook - PDFPesticides
Use and Misuse and Their Impact in the Environment
- Marcelo Larramendy, Sonia Soloneski, Marcelo Larramendy, Sonia Soloneski(Authors)
- 2019(Publication Date)
- IntechOpen(Publisher)
When applied to crops or directly to the soil, for example, systemic insecticides, organophosphates, and carbamates generally persist from only a few hours to several months. However, they have been fatal to large num-bers of birds on turf and in agriculture and negatively impacted breeding success in birds [29]. Nanopesticides or nanoplant protection products represent an emerging technological development that, in relation to pesticide use, could offer a range of benefits including increased efficacy, durability, and a reduction in the amount of active ingredients that need to be used [30]. Biopesticides are natural products that can be considered as sufficient alterna-tive of synthetic pesticide in pest management. 3. Pesticides in agriculture and their benefits The farmers around the world had used different methods and ways to fight the causes that lead to reducing crop yield, most of these methods were simple and traditional, and the result were not satisfactory until the use of pesticide application started. Pesticides include natural and synthetic substances used to control harmful pests such as insects, plant disease organisms, and weed, as well as many other living organisms that endanger the food supply, health, or comfort [8]. The word “pesticides” is a term for all insecticides, herbicides, fungicides, rodenticides, wood preservatives, garden chemicals, and household disinfectants that may be used to kill some pests [31]. A pesticide controls any pest including vectors of human or animal diseases and unwanted species of plants or animals causing harm or interfering with the production, processing, storage, or marketing of food and agricultural com-modities [32]. Pesticides are a chemical group widely used by humans, both to protect the production from harmful organisms and quality of crops and for control of vectors and pests of public health [33].
eBook - PDF- Robert Emmons, Frank Rossi, Ph.D.(Authors)
- 2015(Publication Date)
- Cengage Learning EMEA(Publisher)
Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 274 Chapter 13 themselves and the environment if they use them. Methods of reducing pes-ticide use are explained in Chapter 17, which discusses integrated pest man-agement techniques. Types of Pesticides Numerous Types of Pesticides are used to control various pests. Insecticides are chemicals used to control insects. Most insecticides kill the insect pest by disrupting its nervous system. These toxic chemicals enter the insect’s body when it comes into contact with the insecticide. A second type of insecticide Figure 13-1 A nematode feeding on the roots of a turfgrass plant. This chapter is simply an introduction to pesticides. Before handling pes-ticides, a worker must be thoroughly trained by an experienced applicator and be educated in all the different aspects of pesticide use. There are numerous reports of serious problems resulting from carelessness or inade-quate understanding of a chemical. For example, an inexperienced applica-tor treated golf course fairways on a very hot day with the wrong formulation of 2,4-D herbicide, and most of the grass died. The form he used was injurious to turf during periods of high temperatures because the grass was stressed and susceptible to injury. Obviously this was a disaster but at least no one was injured in this case. TURF TIP Copyright 2016 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 275 Pesticides acts as a stomach poison and must be ingested (swallowed) by the insect to be effective.
- Sharangi, Amit Baran(Authors)
- 2021(Publication Date)
- Daya Publishing House(Publisher)
Pesticide –An economic poison defined in most state and federal laws as any substance used for controlling, preventing, destroying, repelling, or mitigating any pest. Includes fungicides, herbicides, insecticides, nematicides, rodenticides, desiccants, defoliants, plant growth regulators, etc. Physical selectivity –Refers to the use of broad-spectrum insecticides in such ways as to obtain selective action. This may be accomplished by timing, dosage, formulation, etc. This ebook is exclusively for this university only. Cannot be resold/distributed. Physiological selectivity –Refers to insecticides that are inherently more toxic to some insects than to others. Phytotoxic –Injurious to plants. Piscicide –Chemicals used to kill fish. Poison control center –Information sources for human poisoning cases, including pesticides, usually located at major hospitals. Poison –Any chemical or agent that can cause illness or death when eaten, absorbed through the skin, or inhaled by humans or animals. Polymerization –A chemical reaction in which individual molecules combine to form a single large chemicl molecule (a polymer). Usually involves the release of a lot of energy. Postemergence –After emergence of the specified weed or crop. Ppb –Parts per billion (parts in 10 6 parts) is the number of parts of toxicant per billion parts of the substance in question. ppm –1.Parts per million. Generally used to express small concentrations of one substance in a mixture. 2.Parts per million (parts in 10 6 parts) is the number of parts of toxicant per million parts of the substance in question. They may include residues in soil, water, or whole animals. Predacide –Chemicals used to poison predators. Preplanting treatment –Made before the crop is planted. Propellant –An inert ingredient in selfpressurized products that produces the force necessary to dispense the active ingredient from the container.
eBook - PDF- Sinha, Asha(Authors)
- 2021(Publication Date)
- Biotech(Publisher)
Painstaking investigations have shown it to be signally effective against many of the most destructive insects that feed upon crops.” (Scientific American, July 1944). To be acceptable, pesticides must not have strong toxicity toward non-target organisms, especially humans. Yet, to be efficient, they must be highly toxic toward their intended targets. The mechanism of this type of selectivity is often the targeting of a molecular target site that is found only in the pest or, if in other organisms, is particularly vulnerable in the pest; e.g ., an enzyme form that is significantly different from that of other organisms (Duke et al ., 2010). Chemicals are, beyond doubt, the cheapest and miraculously effective means of pest management and hence are still the most popular means to manage pests but since last some decades, the voices against this so treasured a measure of pest management are becoming louder with data showing harm done to the ecology and environment by these chemicals to varying extents because excessive use of these chemicals has led to increased environmental pollution, harmful effects on human health and resistance among pests to the chemicals used. This has driven the researchers to start searching for less harmful yet effective alternatives. With increasing pressure on several components of environment and ecology that has emanated from the unscrupulous use of inorganic plant protection chemicals in agriculture that is so much talked of in the modern times with examples being ubiquitous and so much conspicuous, we are now compelled to seek for the environmentally and toxicologically safer, more selective and efficacious pesticides. There is, therefore, the need to screen for safe and effective biodegradable pesticides with non-toxic effects on non-target organisms.
eBook - PDFAgricultural Pollution
Environmental Problems and Practical Solutions
- Graham Merrington, Dr Linton Winder Nfa, R. Parkinson, Mark Redman, L. Winder(Authors)
- 2002(Publication Date)
- CRC Press(Publisher)
The actual rates of pesticide application to UK farmland are gradually declining although the spray area, now exceeding 40 million hectares, is increasing (MAFF, 2000d). Pesticide usage in the UK (discounting sulphuric acid) has declined by over 19% in the last 10 years. This is attributed to moves to newer, more 'active' molecules applied at lower rates coupled with adoption of reduced rate application, particularly of fungicides where disease pressure is low (MAFF, 2000d). The trend in the decline in usage looks to continue with the stated UK government policy of limiting pesticide use '...to the minimum necessary for the effective control of pests compatible with the protection of human health and the environment' (DoE/MAFF, 1995). This chapter describes the different Types of Pesticides and their modes of action, identifies the pollution problems that they may cause, and discusses practical options for minimising their environmental impact. 7.2 PESTICIDES AND THEIR APPLICATION Pesticides are used to control a wide range of agricultural pests, diseases and weeds (Table 7.2). They are also present in a number of veterinary products to control some of the ecto- and endo-parasites encountered in livestock farming. Pesticide products 160 Chapter 7 contain a number of constituents, including the active ingredient that kills or controls the target organism as well as a number of additives. These additives include solvents, surfactants, liquid or solid carriers, safeners (to reduce the potential of a pesticide harming the crop itself), and adjuvants (added to a pesticide to increase its efficiency). Table 7.2 Common pesticides and their target organisms.
eBook - PDFProduce Degradation
Pathways and Prevention
- Olusola Lamikanra, Syed H. Imam(Authors)
- 2005(Publication Date)
- CRC Press(Publisher)
361 11.2.7 Herbicides ................................................................................... 361 11.2.7.1 Classi fi cation of Herbicides, Their Application and Mode of Action .................................................. 362 11.2.7.2 Herbicide Selectivity ................................................. 367 11.2.8 Rodenticides and Avicides .......................................................... 368 11.2.9 Plant Growth Regulators ............................................................. 368 11.2.10 Desiccants and Defoliants .......................................................... 371 11.3 Risks Associated with Pesticides and Strategies to Reduce Them .......... 371 11.4 Summary .................................................................................................... 373 References .............................................................................................................. 373 342 Produce Degradation: Reaction Pathways and their Prevention 11.1 INTRODUCTION Produce, and crop plants in general, can be attacked by numerous pests, mainly insects, nematodes, and fungi. Moreover, various weeds may compete with the crop plants for moisture, nutrients, and light. Ever since the dawn of agriculture, human-kind has constantly struggled with pests and weeds to increase crop yields and provide an adequate supply of food. The idea of combating them using chemicals can be traced back to ancient Greece and Rome, where burning sulfur helped to avert diseases and insects. Other examples can be found throughout history [1,2]. However, it was not until the 20th century when the era of mass-produced and applied synthetic organic pesticides began and chemical pest control became an integral part of modern agriculture that we were able to sustain a rapidly growing world population with land capacity to spare. Nevertheless, every coin has two sides, and the use of pesticides is also associated with certain risks.
eBook - PDF- Carroll Shry, H. Reiley(Authors)
- 2016(Publication Date)
- Cengage Learning EMEA(Publisher)
Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 4 UNIT Key Terms aerosols attractants biological biorational insect insecticides pheromones repellents synthetic compounds Competencies to Develop After studying this unit, you should be able to: ▸ ▸ identify common insect pests and select an effective control method for each. ▸ ▸ describe the seven ways in which insects are killed by insecticides and the type of insect against which each is most effective. ▸ ▸ list the names and characteristics of the three major groups of insecticides (according to their chemical makeup). ▸ ▸ compare the six ways in which insecticides are applied. ▸ ▸ explain the relationship between the life cycle of insects and timing of insecticide application. ▸ ▸ identify the common biological controls of insects. ▸ ▸ illustrations of insect pests ▸ ▸ live insects ▸ ▸ recommendations for spraying from the local extension service ▸ ▸ insecticides with labels (none should be highly toxic) ▸ ▸ spraying and dusting equipment ▸ ▸ safety gear, including elbow-length protective gloves and respirator ▸ ▸ smartphone apps: ● ● Pest Portal ● ● Spectracide ● ● Calibrate My Sprayer ● ● GardenCompass ● ● Ortho Problem Solver ▸ ▸ safety data sheet (SDS) (Refer to Unit 17) Materials Insecticides 18 UNIT Objective To identify insect pests and select and apply the appropriate synthetic (man-made), biological, or biorational (derived from items in nature) insecticides. Copyright 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
- Willis B. Wheeler(Author)
- 2002(Publication Date)
- CRC Press(Publisher)
Finally, biocontrol has an overwhelming record of human and environmental safety compared to chemical pesticides. Some of the disadvantages of biological control include the following. 1. As stated, biocontrol agents are generally host-specific. That is, typi cally, each agent is active against a single pest species or a disease. Therefore, the farmer or the user who is faced with several different pests must resort to many different biocontrol agents and must seek several supplementary control methods or use a broad-spectrum pesti- cide that will control all of the pests (e.g., methyl bromide as a soil fumigant) or certain categories of pests (e.g., broad-spectrum herbi- cides). 2. Because biological control agents, as living organisms, depend on multistep and multifactorial interactions to be effective, their success as biocontrol agents is notoriously unpredictable. 3. The slow rate of action of biological control may not satisfy the user’s needs. Whereas the slower actions of biocontrol agents may have ad vantages (see above), the users may require quicker solutions to their pest problems. In some crops, there may be time constraints that pre clude the use of biological control agents. For example, a crop may have a short period of pest attack during which a biological control agent must be effective to protect the crop. A biocontrol agent that requires a period of several weeks or months to be effective may not serve the purpose. However, the concept of “compound interest” may be applied to this scenario; a biocontrol agent may be introduced and allowed to build up over several years and provide gradual pest sup pression. There are many examples in the literature attesting to the fact that this situation occurs. For example, fields that have been left untreated with chemical pesticides for several years tend to gradually build up a strong suite of beneficial agents that protect against deleteri ous organisms.
eBook - PDF- Laichattiwar Mukesh Anandrao(Author)
- 2019(Publication Date)
- Delve Publishing(Publisher)
Two main classes of pesticides which target insects are used in greenhouses. They are broad-spectrum and narrow-spectrum pesticides. Narrow-spectrum pesticides are also known as selective pesticides. The broad-spectrum pesticides are very active and they attack several mite and insect pests and they can be of good choice if diverse horticultural crops are grown. Narrow-spectrum pesticides are active only on certain mite and insect pests. 10.2 IMPROVING PERFORMANCE It was believed that pesticide suppression led to pesticide resistance. This can be acceptable in some cases but there are several factors which also result in reduced performance of the pesticide. The factors responsible for this reduced performance can range from water quality issues to application techniques. Some of the factors which reduce the performance of the pesticides are described in the following sections. 10.3 IDENTIFICATION OF PESTS We need to identify mite and insect pests before pesticide selection as some of the pesticides can have a narrow range target on mite and insect pests on which they work. Some registered pesticides can be active on one group of pests like mites and some are active against two insect types like aphids and thrips. It is always important to correctly identify the pest and for that one should always keep reference images handy. Another way is to send samples to a university based or plant diagnostic center. If the pest is identified with extreme confidence then we can select appropriate pesticide. It is crucial to know the life cycle, behavior and biology of a pest as some of the life stages can be positioned on the plants and some of them can be susceptible to pesticides. 10.4 COVERAGE OF PESTICIDES All the plant parts such as flowers stem and leaves are important in reducing mite and insect pest with the help of pesticides via contact. The lower and the upper leaf surfaces should receive a good volume of the spray solution.
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