These products are typically used by the poultry industry to disinfect their facilities. Certain proteins found in cells of the central nervous system of humans and animals may exist in abnormal, infectious forms called "prions. Biological agents such as Bacillus anthracis spores can cause a threat to public health and national security.
EPA has the authority to issue emergency exemptions for pesticides for use in anthrax spore decontamination efforts. Skip to main content. Related Topics: Pesticides and Consumers Pesticides. Problems With Overuse of Pesticides Pesticide Resistance : In an attempt to achieve better or total pest control, resistance problems have increased because pesticides are applied more frequently and at higher dosage rates. These tactics have resulted in increased selection pressure.
Naturally resistant individuals in a pest population are able to survive pesticide treatments. The survivors breed and pass on the resistance trait to their offspring.
With each passing generation, the pest population becomes more difficult to control with the same pesticides as compared with earlier generations. Reducing pesticide use and alternating among classes of pesticides with different modes of action can help to lessen the possibility of pest resistance. Managing pest resistance is very important in helping to prolong the effective life of needed pesticides. Toxicity to Natural Enemies and Other Non-target Organisms : Natural enemies of pest species can be very helpful in keeping pest populations at lower levels.
These beneficial organisms include organisms that are predators, parasites, or competitors to the detriment of the pest species. For example, aphids do not reach pest levels every year because many different natural enemies help to keep them in check.
Unfortunately, many broad-spectrum, non-selective pesticides are more detrimental to numerous beneficial species than to the pests. Ever since the first cultivation of plants for food, these plants have needed to be protected against pests and diseases.
The level of sophistication of this protection has increased with time. The Romans used ashes, crushed cypress leaves and diluted urines to protect their crops. Today, a wide range of synthetic products have been developed to give much safer, more targeted and effective control of pests and diseases.
Planting dates Goyal and Kanta, a , and barrier crops teosinte Zea spp. Goyal and Kanta, b were found to be effective against maize stem borer Chilo partellus in India. The brown seaweeds Spatoglossum asperum and Sargassum swartzii can be used as manure to protect plants tomato Solanum lycopersicum L. In India, rodents are pests in agriculture, horticulture, forestry, animal husbandry as well as in human dwellings and rural and urban storage facilities. Cultural methods, such as clean cultivation, proper soil tillage and crop scheduling, barriers, repellents and proofing that reduce the rodent harbourage, food sources and immigration may have long lasting effects Parshad, Managing pest populations using devices which affect them physically or alter their physical environment is called physical control.
Exposure to sun rays, steaming, moisture management especially for stored grain pests, and light traps for attracting various kinds of moths, beetles and other pests are different methods used in physical control.
For example steaming woolen winter clothes help in eliminating population of the woolly bear moth, Antherenus vorax waterhouse Dhaliwal et al. Hot water treatment of plant storage products like corns, and bulbs helps to kill many concealed pests such as eelworms and bulb flies. Mechanical control refers to suppression of pest population by manual devices.
It includes various practices such as hand picking, trapping and suction devices, clipping, pruning and crushing of infested shoots and floral parts, and exclusion by screens and barriers to keep away house flies Musca domestica , mosquitoes and other pests. In south-eastern Australia, the common starling Sturnus vulgaris is an established invasive avian pest that is now making incursions into Western Australia which is currently free of this species.
Trapping with live-lure birds is suggested to be the most cost-effective and widely implemented starling control technique Campbell et al. Numerous wildlife species such as coyotes Canis latrans Say , squirrels Sciuridae family , and birds are known pests of California agriculture in the United States. For these pests, different non-lethal control options including habitat modification, exclusionary devices, and baiting are generally preferred Baldwin et al.
Mechanical weed control is mainly associated with tillage practices which are performed with special tools such as harrows, hoes, and brushes in growing crops. Increased knowledge about side effects of herbicides has further driven the interest in adoption of mechanical weed control thus increasing the prevalence of organic farming Rueda-Ayala et al.
Trapping using yellow colored sticky traps is an effective way for controlling tephritid flies Dhaliwal et al. Host plant resistance HPR is the genetic ability of the plant to improve its survival and reproduction by a range of adaptations as compared to the other cultivars when exposed to the same level of pest infestation.
HPR offers the most effective, economical and eco-friendly method of pest control Sharma and Ortiz, , and is considered to be a key element of the IPM strategy. Due to this, identifying and developing HPR has always been a major thrust area of plant breeding, and a number of breeding programs aiming to develop pest resistant crops have been deployed in almost all the cultivated crop species. Chahil and Kular, , wheat Triticum aestivum L.
Additionally, availability and access to various germplasm collections have increased the scope of widening the gene-pool of cultivated crops and further identifying and developing HPR. Wild species are especially known to possess a rich repository of genes against various defense traits as they have evolved under different geographic locations. Colon and Budding, , wheat against powdery mildew Erysiphe graminis from wild emmer wheat Triticum dicoccoides Reader and Miller, and mustard Brassica juncea against Sclerotinia sclerotiorum from Erucastrum cardaminoides Garg et al.
The advent of new biotechnological and molecular approaches has opened the way to develop resistant genotype that could not only reduce the pesticides application, but it also has a potential to be a part of IPM. Development of resistant genotypes in classical breeding is met with several challenges such as it is time consuming, desired traits are linked with the undesirable traits linkage drag and most importantly lack of resistant genotypes in the gene pool.
On the other hand, use of biotechnology in crop improvement ensures the development of pest-resistant genotypes in a comparatively short period of time and minimizes the effects of linkage drag. One of the classic examples where biotechnology was successfully deployed to develop resistant genotype is by the synthesis of transgenic plants which involves modifying plant traits by inserting foreign DNA from a different species De la Pena et al.
A number of different crops including cotton, rice, mustard, and maize have been modified up to now to engineer the genotypes against various biotic stresses Ahmad et al.
One of the most successful examples of synthesis of transgenic genotype against pest resistance is in cotton where the gene coding for Bt toxin from the bacterium Bacillus thuringiensis Bt was inserted leading cotton genotypes to produce Bt toxin in its tissue Pray et al.
The lepidopteran larvae that fed on the transgenic plants were killed due to Bt toxin eventually decreasing the amount of pesticide applied to the field. Examples of transgenic crops that have been developed with a potential to reduce pesticides use are abound and few of them include potato lines against potato tuber moth Phthorimaea operculella expressing Cry1Ab Kumar et al.
Another strategy where biotechnology and molecular approaches have been deployed to combat biotic stresses involves the use of RNA interference RNAi technique. This ultimately interferes with the development and survival of the target pest.
RNAi has emerged as a powerful functional genomics approach and it has been used to engineer several crops against number of insect-pests. When such an advanced and effective approach is combined with IPM, it has a great potential to decrease chemical use in agricultural and other ecosystems. The process of using natural enemies of particular pests to reduce their populations to such a level where economic losses are either eliminated or suppressed is called biological control.
Traditionally the most important biocontrol agents are parasitoids, predators and pathogens. Biological control involves three major techniques, viz. Biocontrol agents include vertebrates, nemathelminthes flatworms, and roundworms , arthropods spiders, mites, and insects , pathogens like viruses, bacteria, protozoa, fungi and rickettsiae all of which play a dynamic role in natural regulation of insect and mite populations Dhaliwal et al.
In , the Indian Mynah, Acridotheres tristis Linnaeus , was introduced to control red locust in Mauritius. First significant success in controlling a pest was achieved on the suggestion of C. Riley of California USA in The Vedalia beetle Rodolia cardinalis Mulsant , was introduced from Australia into California USA for the control of cottony-cushion scale Icerya purchasi maskell on citrus plants. This scale insect had been accidentally introduced earlier from Australia Dhaliwal et al.
Biological control of weeds has been very successful worldwide. There are about 41 species of weeds which have been successfully controlled using insects and pathogens as biocontrol agents. Also, 3 weed species have been controlled using native fungi as mycoherbicides Mcfadyen, A total of 12 insects were released in Australia against prickly pear Opuntia stricta , out of these, Dactylopius opuntiae and Cactoblastis cactorum were responsible for the successful control of prickly pear weed Julien and Griffiths, In the past decade, Australia has released 43 species of arthropods and pathogens in 19 different projects for successful biological control of many exotic weeds.
Effective biological control was achieved in several projects and outstanding success was achieved in the control of rubber vine Cryptostegia grandiflora , and bridal creeper Asparagus asparagoides Palmer et al. Examples of biological control are available for other organisms like helminthes, nematodes, fungi, bacteria etc.
A nematophagous fungus Monacrosporium thaumasium was found to be effective in controlling cyathostomin, one of the most important helminthes in tropical region of southeastern Brazil Tavela et al. Trichoderma species are free-living fungi that have been used to control a broad range of plant pathogenic fungi, viruses, bacteria and nematodes especially root-knot nematodes Meloidogyne javanica and M. Biopesticides encompass a broad array of microbial pesticides, plant pesticides and biochemical pesticides which are derived from micro-organisms and other natural sources, and processes involving the genetic incorporation of DNA into agricultural commodities.
The most commonly used biopesticides include biofungicides e. Applications of microbial insecticide, Chromobacterium subtsugae for suppression of pecan weevil Curculio caryae Horn , and combination of eucalyptus extract and microbial insecticide, Isaria fumosorosea Wize for control of black pecan aphid Melanocallis caryaefoliae Davis were found promising as alternative insecticides Shapiro-Ilan et al.
Entomopathogenic nematodes EPNs belonging to the families Heterorhabditidae and Steinernematidae are potentially used in South Africa as biocontrol agents against vine mealybug Planococcus ficus Signoret le Vieux and Malan, Spinosad was found effective in controlling Colorado potato beetle Leptinotarsa decemlineata in Iran, and is recommended for use in IPM program for Colorado potato beetle Soltani and Agricultural, In China, entomopathogenic fungus Beauveria bassiana has shown great potential for the management of some bark beetle species including red turpentine beetle RTB Dendroctonus valens LeConte , a destructive invasive pest Zhang et al.
The allelopathic properties of plants can be exploited successfully as a tool for weed and pathogen reduction. Numerous growth inhibitors identified from these allelopathic plants are responsible for their allelopathic properties and may be a useful source for the future development of bio-herbicides and pesticides Xuan et al. A combination of coleopteran-active toxin, Bacillus thuringiensis Cry3Aa protoxin and protease inhibitors, especially a potato carboxypeptidase inhibitor, have efficiency in preventing damage to stored products and grains by stored grain coleopteran pests Oppert et al.
Sometimes cultural and other agro-technical practices are not sufficient to keep pest population below economic injury level lowest pest population density that will cause economic crop damage.
Therefore, the chemical control agents are resorted to both as preventive and curative measures to minimize the insect pest damage. A good pesticide should be potent against pests, should not endanger the health of humans and non-target organisms, and should ultimately break down into harmless compounds so that it does not persist in environment.
Both relative and specific toxicities of the pesticide need to be estimated in order to determine its potency. It is very important to know spray droplet size and density chemical dosage, application timing, which can provide adequate pest control.
There is also a need for research into the development of suitable packaging and disposal procedures, as well as refining of the application equipment.
All of these shall rationalize the use of pesticides, so that they can be used in an acceptable way. Very strict laws should be enacted to protect wildlife and other non-target organisms. Following directions on the pesticide label can prevent injury to non-target organisms. However, when these directions are not followed, benefits from pesticides can be outweighed by the harm and risk associated with pesticides Fishel, During pesticide application, things that need to be considered are timing of insecticide application, dosage and persistence, and selective placement of insecticides as discussed below.
The timing of pesticide application is an important factor to consider before doing any pesticide application. Appropriate application time can ensure not only maximum impact on the target organisms but also least impact on beneficial organisms.
Pesticide application timing mainly depends on availability of weather window, time at which pests can be best controlled, and when least damage will be caused to non-target organisms and environment.
Flowering period in crops and middle of the day are the times when bees are more prone to insecticides. Hence, insecticide application should not happen at those times to avoid decline in bee populations.
Time of insecticide application should coincide with the most vulnerable stage of insect life cycle. Monitoring of insects in the field is thus extremely important for knowing the stage of insect pest in the field. Monitoring systems are available for most of the insect pests, but spray regime or experiments need to be carried out to determine the most appropriate time for insecticide application for insects for which monitoring systems are not available Hull and Starner, ; Richter and Fuxa, Time of the day and season of the year are also important to consider when making pesticide applications.
The early morning and evening hours are often the best times for pesticide application because windy conditions are more likely to occur around midday when the temperature warms near the ground level. This causes hot air to rise quickly and mix rapidly with the cooler air above it, favoring drift.
During stable conditions, a layer of warm air can stay overhead and not promote mixing with colder air that stays below and closer to the ground. Inversions tend to dissipate during the middle of the day when wind currents mix the air layers. It is very important that applicators recognize thermal inversions and do not spray under those conditions. A temperature or thermal inversion is a condition that occurs naturally and exists when the air at ground level is cooler than the temperature of the air above it.
Wind speed is the most important weather factor influencing drift. High wind speeds will move droplets downwind and deposit them off the target. On the other hand, dead calm conditions are never recommended due to likelihood of temperature inversions Fishel and Ferrell, Drifting of pesticides increases the possibility of injury to pollinators, humans, domestic animals and wildlife.
It is recommended not to spray in wind speed above 2. Pesticide application should not be made just before rain because pesticides can be washed off by the rain without any impact on the target pest.
Pesticide dose should be sufficient but no greater than the level required for best results. The pesticide manufacturer sets the dose to ensure an acceptable level of control, producing acceptable residue levels, and maximizing returns per unit of formulated insecticide.
Persistent pesticides have their benefit of longer persistence on the target and therefore requires less frequent spraying compared to non- persistent pesticides. But care should be taken while using persistent pesticides since these might diminish benefits from natural enemies even at lower doses.
If an insecticide is persistent in nature, chances of insecticide residues being harmful to natural enemies are greatly increased Dent, Distribution of pesticides in the field should be such that maximum target cover is achieved. Most of the pesticides are applied in liquid form and thus the droplet size is very important in determining their effectiveness.
Small droplets provide better coverage and greater likelihood of coming in contact with the target compared to larger droplets that can bounce off the plant surface very easily. The disadvantage with smaller and bigger droplets is the increased chance of drift and therefore a balance has to be considered between smaller droplets to obtain the maximum effectiveness and reduced drift.
In situations where crops are grown on beds covered with plastic mulch, pesticides should be injected into soil at the time the plastic is laid or injected afterward through drip irrigation system to achieve maximum pesticide effectiveness. Additionally, liquids that form foams following injections can be injected into small spaces that are or might be inhabited by termites or other small creatures. Although, pesticides were used initially to benefit human life through increase in agricultural productivity and by controlling infectious disease, their adverse effects have overweighed the benefits associated with their use.
The above discussion clearly highlights the severe consequences of indiscriminate pesticide use on different environmental components. Some of the adverse effects associated with pesticide application have emerged in the form of increase in resistant pest population, decline in on beneficial organisms such as predators, pollinators and earthworms, change in soil microbial diversity, and contamination of water and air ecosystem.
The persistent nature of pesticides has impacted our ecosystem to such an extent that pesticides have entered into various food chains and into the higher trophic levels such as that of humans and other large mammals. Some of the acute and chronic human illnesses have now emerged as a consequence of intake of polluted water, air or food.
This is the time that necessitates the proper use of pesticides to protect our environment and eventually health hazards associated with it. Alternative pest control strategies such as IPM that deploys a combination of different control measures such as cultural control, use of resistant genotype, physical and mechanical control, and rational use of pesticide could reduce the number and amount of pesticide applications.
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