Review on the Impact of Insecticides Utilization in Crop Ecosystem: Their Prosperity and Threats

Abstract

Pesticide covers a wide range of compounds including insecticides, fungicides, herbicides, rodenticides, molluscicides, nematicides, plant growth regulators, and others. Among them, organochlorine insecticides, used successfully in controlling a number of diseases, such as malaria and typhus, were banned or restricted after the 1960s in most of the technologically advanced countries. The introduction of other synthetic insecticides—organophosphate insecticides in the 1960s, carbamates in the 1970s, and pyrethroids in the 1980s, and the introduction of herbicides and fungicides in the 1970s–1980s contributed greatly to pest control and agricultural output. Ideally, a pesticide must be lethal to the targeted pests, but not to nontarget species, including man. Unfortunately, this is not the case, so the controversy of the use and abuse of pesticides has surfaced. The rampant use of these chemicals, under the adage, “if little is good, a lot more will be better” has played with humans and other life forms. The known ecological impacts of insecticides on terrestrial and aquatic ecosystems are reviewed in this chapter. Awareness of the impacts that insecticides are having in our world may help to introduce the management practices that aim at reducing and mitigating those impacts.

1. Introduction

Insecticides (natural or synthetic) are used in agriculture to control pests, weeds, and diseases in plant species. Herbicides, insecticides, fungicides, rodenticides, nematicides, and others are examples of pesticides. Pesticides became an important tool for plant protection and crop yield enhancement during the agricultural development process. A pest infestation accounts for approximately 45% of annual food production: therefore, effective pest management through the use of a diverse range of pesticides is required to combat pests and increase crop production [1]. However, in the latter half of the nineteenth century, rapid growth in the global economy, including both the industrial and agricultural sectors, resulted in a steady increase in the production and use of agricultural-based chemicals, which frequently have disastrous effects on the environment. Inadequate use of pesticides and some other persistent organic pollutants in agricultural soils has wreaked havoc on future consequences. Due to their bioaccumulation properties and high toxicity, the persistent and ubiquitous nature of various agricultural-based pesticides and other organic pollutants has caused destruction to humanity. These pesticides are known to impair the functioning of living organisms’ metabolic and reproductive systems [2]. Certain pesticides, such as DDT, aldrin, hexachlorobenzene, dieldrin, mirex, endrin, chlordane, and heptachlor, have negative effects on human health and the environment [3].

Currently, approximately 2 million tonnes of pesticides are used globally, with 47.5% being herbicides, 29.5% being insecticides, 17.5% being fungicides, and 5.5% being other pesticides [4]. China, the United States, Argentina, Thailand, Brazil, Italy, France, Canada, Japan, and India are the top 10 pesticide-consuming countries in the world. Furthermore, it is predicted that global pesticide usage will rise to 3.5 million tonnes by 2020 [5].

They include ovicides and larvicidal, which are used to kill insect eggs and larvae. Insecticides are used extensively in agriculture, medicine, and industry, and by consumers. Insecticides are credited with significantly increasing agricultural productivity in the twentieth century [6]. Almost all insecticides have the potential to drastically change ecosystems; many are harmful to humans and also to animals and some become focused as they move up the food chain.

2. Classification of insecticides

2.1 Organochlorine

Organochlorines (chlorinated hydrocarbons) having organic compounds are attached to five or more chlorine atoms. It is the first group of pesticides that are synthesized and used in public health and agriculture. It is used against the management of a wide range of insects and having long-term residual effects in the atmosphere. The mode of action of these insecticides is disrupting the nervous system of the insects which caused paralysis and convulsions, which leads to death (Figure 1).

Figure 1.

Classification of insecticides (Source: [7]).

2.2 Organophosphates

The group “organophosphate” pesticides are considered to be one of the broad-spectrum pesticides, which manage various numbers of pests because of their multiple functions. The organophosphate pesticides are biodegradable, cause very low environmental pollution, and are slow pest resistance [8].

2.3 Carbamates

The carbamates insecticides are similar to the organophosphates insecticides. Carbamates are derived from carbamic acid where organophosphates are the derivatives of phosphoric acid. Mode of action of carbamate pesticides and organophosphate pesticides are similar, that is, affecting the nervous system, that is, the transmission of nerve signals that caused the death [9].

2.4 Synthetic pyrethroid

A synthetic pyrethroid is a group of pesticides that are organic pesticide group that can be synthesized from natural pyrethrins.

3. Pesticides production in India

India is the fourth largest producer of agrochemicals followed by the USA, Japan, and China. Worldwise utilization of agrochemical regarding pest management India has the ninth rank (Figure 2). In India, Maharashtra ranks first in the consumption of pesticides regarding crop protection followed by Uttar Pradesh and West Bengal having 13,243, 11,557, and 3630 MT consumption of pesticide, respectively [10]. In India, maximum utilization of pesticides takes place regarding the management of pest of cotton (45%) followed by rice (22%) and vegetable (9%) as globally comparing the highest in fruit and vegetable (26%) followed by cereals (18%) (Figure 3).

Figure 2.

Pesticide consumption in different countries of the world (Source: Indian Agrochemical Industry Report, 2016).

Figure 3.

Crop wise consumption of pesticides.

3.1 Benefits of pesticides

Farmers have made significant growth in food production by using pesticides over the last 60 years. They did this primarily to prevent or reduce agricultural losses caused by pest activity, which resulted in increased yield and greater availability of food at a reasonable price throughout the year. In most countries, agricultural productivity has increased dramatically as a result of the use of pesticides (Figure 4). For example, wheat yields in the United Kingdom [12] corn yields in the USA [13], and total yields in Russia and other countries were enhanced enormously [14, 15, 16]. It has long been assumed that diets rich in fresh fruits and vegetables far compensate the risks of eating crops with very low pesticide residues [17]. Better nutrition and less drudgery both improve the quality of life and the length of life [18]. Improved medical care and drug treatments, as well as hygiene, having all played a significant role in extending lives, but the importance of nutritious, safe, and affordable food as a health promoter that increases life expectancy should not be underestimated [19, 20]. Controlling a wide range of vectors of human and livestock disease, thereby reducing the number of infected people and deaths, as well as preventing the spreading of international disease, is one of the most obvious benefits of widespread pesticide use. The most effective way to combat vectors is to kill them. According to the World Health Organization, life will be unacceptably dangerous for a large proportion of humanity if chemical control methods are not available. Pesticides are essential in the destruction of many living things, which has a negative effect on human activities, infrastructure, and everyday activities. Insecticides have been used to kill unwanted organisms in many particular sectors of human action, such as the prevention of accelerated corrosion of metal structures, the maintenance of turf on sports pitches, cricket grounds, and golf courses, and assisting in the facilitation of a hugely popular pastime that provides fresh air and sunshine for thousands of people in domestic and decorative gardening.

Figure 4.

Pesticides production in India (Source: [11]).

Pesticides can provide a variety of benefits, but many of these advantages go unobserved by the general public. The most important and simplest to calculate advantages are also the financial advantages for farmers derived from the protection of farm outcome and quality as well as the reduction of other expensive inputs such as labor and fuel. Estimates of global pest failures for eight crops in some regions revealed that pest-induced losses exceeded 50% of attainable agricultural production [21]. Pests destroyed 15% of crops, disease pathogens and weeds each accounted for 13%, and post-harvest pest infestations accounted for 10%. Agricultural production would decline and food costs would rise steeply if pesticides were not used. Farmers would be less competitive in the international markets for major commodities if they produced less and charged more. Preventing or decreasing agriculture sector losses to pests through the use of pesticides improves yields and thus ensures consistent supplies of agricultural produce at reasonably priced prices for consumers. It also enhances the quality of the food in terms of esthetic appeal, which is important to customers.

Insecticides are also commonly used in a number of other situations, many of which the general public is unaware of. In the same manner that pests in agriculture and public health cause adverse effects such as losses, contamination, and damage, those organisms have a negative effect on social activities, infrastructure, and everyday materials when left unchecked. Pesticides play a significant, but often unseen, role in mitigating this negative effect. Thus, the advantages of pesticides can accumulate to a range of different recipients, not just farmers or buyers, but also to society as a whole.

Other advantages include the preservation of esthetic quality, the protection of human health from disease-carrying organisms, the eradication of nuisance that causes diseases, and the preservation of other organisms, such as endangered species. Insecticides are often used in ways which we often take it for granted in our businesses and homes. For example, the controlled use of insecticides in processing, manufacturing, and packaging facilities protects raw commodities and packaged grocery products from insect contamination. Pesticides are often used in supermarkets to control rodents and insects drawn to food and food waste.

According to Davis et al. [22], nearly all families (97.8%) used pesticides at least once per year, and two-thirds used insecticides more than five times each year. The home was the most common location for family pesticide use, with 80% of families using pesticides at least once per year. This was followed by the use of herbicides to control yard weeds (57% of families) and insecticides to control fleas and ticks on pets (50% of families). Pesticides were also used by a significant number of families in their gardens or orchards (33%). It is obvious that proper pesticide use improves our quality of life, protects our property, and promotes a healthier environment. These nonmonetary advantages of pesticide use are difficult to quantify. Policymakers have long struggled with how to assign monetary values to things like esthetic value, the survival of certain endangered species, and peacefulness. In practice, such nonmarket advantages are rarely recognized as key by policymakers as positive effects that can be quantified in the marketplace, and thus, they are largely unnoticed. The innovation of a pesticide use profile is usually the first step in calculating the beneficial effects of each pesticide. The lack of an insecticide use database is a major barrier to determining accurate estimates of the impact of changes in insecticide availability (Table 1).

Sr. No.	The primary advantages	The secondary advantages
1.	Controlling disease vectors and nuisances organism	Global benefits
	Human lives saved; Human disturbance reduced; Animal suffering reduced; Increased livestock quality	Less pressure on uncropped land; Fewer pest introductions else where; International tourism revenue
2.	Controlling pests and plant disease vectors	National benefits
	Improved crop/livestock quality; Reduced fuel use for weeding; Reduced soil disturbance; Invasive species controlled	National agricultural economy; Increased export revenues; Reduced soil erosion/moisture loss
3.	Prevent or control of organisms that harm other human activities and structure	Community benefits
	Tree/bush/leaf hazards prevented; Recreational turf protected; Wooden structures protected	Nutrition and health improved; Food safety/security; Life expectancy increased; Reduced maintenance costs

Table 1.

The complexity of the effects, and primary and secondary benefits of pesticides.

Source: Cooper and Dobson [23].

3.2 Impacts of pesticides

They are potentially harmful to humans, animals, other living organisms, and the environment if used incorrectly. It is estimated that about 5000–20,000 people died and about 500,000 to 1 million people get poisoned every year by pesticides [24, 25] at least half of the intoxicated and 75% of those who die due to pesticide are agricultural workers. The rest is being poisoned due to the eating of contaminated food. For control of aphid population on mustard crop, imidacloprid 17.8 SL and thiamethoxam 25 WP were recorded as the most effective. In the biopesticide point of view, M. anisopoliae 1.15 WP was recorded as more effective than B. bassiana 1.15 WP [26].

3.3 Impact on human health

Pesticides might enter the human body through the inward breath of dirty air, residue, and fume that contain pesticides; through oral openness by burning through sullied food and water; and through dermal openness by direct contact with pesticides [27]. Pesticides are showered onto food, particularly foods grown from the ground, and they emit into soils and groundwater, which can wind up in drinking water and pesticide splash can float and contaminate the air. Poisonousness of synthetic substances, length, and greatness of openness decides the level of spiteful effect on human well-being [28]. Pesticide float from rural fields, openness to pesticides during the application and deliberate or inadvertent harming for the most part, prompts the intense sickness in people [29, 30]. Studies build up a connection between pesticides openness and the frequencies of human persistent infections influencing anxious, regenerative, renal, cardiovascular, and respiratory frameworks [31]. The credits of pesticides remember upgraded financial potential for terms of expanded production of food and fiber and the board of vector-borne infections and afterward, their charges have brought about genuine well-being suggestions to man and climate. There is presently overpowering proof that a portion of these synthetic substances does represent an expected danger to people and other living things and undesirable incidental effects to the climate [32]. Exact insights on the well-being impacts of pesticides are not accessible. Notwithstanding, it is assessed that all around the world, consistently somewhere in the range of 1 and 41 million individuals experience the ill effects of openness to pesticides assessed that at least 300,000 individuals kick the bucket from pesticide harming every year, with close to 100% of them from low and center pay nations. In 2008, the World Bank put the quantity of passing at 355,000. Notwithstanding, FAO (2005) suggesting to ongoing information from Sri Lanka demonstrated that 300,000 passing each year might happen in the Asia-Pacific locale alone because of pesticide harming. The study of disease transmission of pesticide openness worldwide is not completely perceived and more often than not under-analyzed as indicated by the Dish American Wellbeing Association, a global general wellbeing organization situated in Washington, D.C. “Pesticide harming cases are under-revealed by 50% to 80% area wide,” detailed the PAHO in 2011, introducing to the Americas (Table 2).

Sr. No.	Active ingredient	Brand name	Manufactory company	Signs and symptoms
1.	Acephate (organophosphate)	Orthene	Kalyani Industries Ltd., India	Headache, excessive salivation and tearing, muscle twitching, nausea, diarrhea. Respiratory depression, seizures, loss of consciousness. Pinpoint pupils.
2.	Aldicarb (N-methyl carbamate)	Temik	Yangzhou Xinhua Chemical Industries, China	Malaise, muscle weakness, dizziness, sweating. Headache, salivation, nausea, vomiting, abdominal pain, diarrhea. Nervous system depression, pulmonary edema in serious cases.
3.	Carbaryl (N-methyl carbamate)	Sevin	Yangzhou Xinhua Chemical Industries, China	Malaise, muscle weakness, dizziness, sweating. Headache, salivation, nausea, vomiting, abdominal pain, diarrhea. Nervous system depression, pulmonary edema in serious cases.
4.	Chlorpyrifos (organophosphate)	Dursban	Dow Chemical Company, USA	Headache, excessive salivation and tearing, muscle twitching, nausea, diarrhea. Respiratory depression, seizures, loss of consciousness. Pinpoint pupils.
5.	Endosulfan (organochlorine)	Thiodan	Hindustan Insecticides Ltd. (HIL),India	Itching, burning, tingling of skin. Headache, dizziness, nausea, vomiting, lack of coordination, tremor, mental confusion. Seizures, respiratory depression, coma.
6.	Malathion (organophosphate)	Cythion	Shri Ram Agro Chemicals, India	Headache, excessive salivation and tearing, muscle twitching, nausea, diarrhea. Respiratory depression, seizures, loss of consciousness. Pinpoint pupils.
7.	Methyl Parathion (organophosphate)	Penncap-M	European Chemicals Agency, Europe	Headache, excessive salivation and tearing, muscle twitching, nausea, diarrhea. Respiratory depression, seizures, loss of consciousness. Pinpoint pupils.
8.	Phosmet (organophosphate)	Imidan	Abhayam Cropsafe Private Limited, India	Headache, excessive salivation and tearing, muscle twitching, nausea, diarrhea. Respiratory depression, seizures, loss of consciousness. Pinpoint pupils.
9.	Pyrethrins (Plant origin)		Green Heaven India (A Herbal Manufacturing Unit) India	Irritating to skin and upper respiratory tract. Contact dermatitis and allergic reactions—asthma.
10.	Pyrethroids (synthetic pyrethrin)	Cypermethrin, permethrin	Sumitomo Chemical India	Abnormal facial sensation, dizziness, salivation, headache, fatigue, vomiting, diarrhea. Irritability to sounds or touch. Seizures, numbness.

Table 2.

Signs and symptoms of acute exposure for several insecticide-active ingredients.

Source: Lorenz [33].

3.4 Impacts on environment

At the point when pesticides are showered in farming yield, they might discover their direction through the air and ultimately end up in different portions of the climate, for example, in soil or water. Pesticides that are applied straightforwardly to the dirt might be washed off and reach close surface water bodies through surface spillover or may permeate through the dirt to bring down soil layers and groundwater [34]. The impacts of pesticides on the natural framework might go from minor deviation on the typical working of the environment to the deficiency of species variety. At some point, utilization of pesticides might cause long-haul remaining impacts while in any case intense deadly impacts. For instance, most organochlorine pesticides are persevering in the climate for a long time, thus bringing about tainting of groundwater, surface water, food items, air, and soil (Table 3).

Sr. No.	Diseases	Reference
1	Diabetes (type 2 diabetes)	Son et al. [35]
2	Birth defects	Winchester et al. [36]; Mesnage et al. [37]
3	Reproductive disorders	Petrelli and Mantovani [38]; Greenlee et al. [39]
4	Cancer (childhood and adult brain cancer; renal cell cancer; lymphocytic leukemia (CLL); prostate cancer)	Lee et al. [40]; Shim et al. [41]; Heck et al. [42]; Xu et al. [43]; Band et al. [44]; Cocco et al. [45]
5	Reproductive disorders	Petrelli and Mantovani [38]; Greenlee et al. [39]
6	Neuro degenerative diseases including Parkinson’s disease, Alzheimer disease	Elbaz et al. [46]; Hayden et al. [47]; Tanner et al. [48]
7	Respiratory diseases (asthma, chronic obstructive pulmonary disease [COPD])	Chakraborty et al. [49]; Hoppin et al. [50]
8	Hormonal imbalances including infertility and breast pain	Xavier et al. [51]

Table 3.

Chronic disease to human due to the pesticides application.

4. Impacts on nontarget organism

Most insect sprays are once applied to kill nuisance; it might form likewise unfavorably non-objective life forms such as worm, normal hunters, and pollinator [52]. Pesticide applications can cause a decrease in the population of the worm. For instance, carbamate bug sprays are exceptionally poisonous to nightcrawlers and a few organophosphates have been displayed to lessen worm populaces [53]. Disgracefully, regular hunters, for example, parasitoids and hunters (fundamental for controlling pest populace level), are generally vulnerable to insect sprays and are seriously influenced [54].

Pollinators such as honey bees, organic product flies, a few scarabs, and birds can be utilized as bio-pointers of biological system measures from various perspectives as their exercises are influenced by natural pressure brought about by pesticides application and living space adjustments [55]. Utilization of pesticides may likewise cause direct loss of creepy-crawly pollinators and indirect calamity to crops as a result of the absence of satisfactory populaces of pollinators [56]. M. anisopliae, B. bassiana, imidacloprid, and thiamethoxam are noted as less toxicity to beneficial insects while managing mustard aphid [57].

5. Impacts on soil micro-flora

The lost and reused utilization of pesticides disturbs this dirt growth. Soil properties and soil miniature vegetation get influenced because of pesticides that may go through an assortment of exploitation, transport, and adsorption/desorption measures [58]. The tarnished pesticides connect with the dirt and its native microorganisms, along these lines changing its microbial variety, biochemical responses, and enzymatic movement [58, 59]. Any adjustment in the microbial variety and soil biomass, in the long run, prompts the unsettling influence in the soil environment and loss of soil fruitfulness. Pesticide application may likewise restrain or kill certain gatherings of microorganisms and dwarf different gatherings by delivering them from the opposition [58]. They may likewise antagonistically influence the dirt essential biochemical responses including nitrogen obsession, nitrification, and ammonification by initiating/deactivating explicit soil microorganisms and additional chemicals [58, 59].

6. Impacts on water and air ecosystem

There are diverse ways by which pesticides can get into water such as unplanned spillage, mechanical profluent, surface runoff and transport from pesticide-treated soils, washing of shower gear after splash activity, float into lakes, lakes, streams and waterway water, ethereal showers to control water-repressing bugs [60]. Pesticides move from fields to different water sources by overflow or in waste actuated by rainstorm or water system [59]. The instability or semi-unpredictability nature of the pesticide compounds likewise establishes a significant danger of barometrical contamination of huge urban communities [61, 62, 63].

7. Conclusion

Pesticides act as the backbone of farmers as well as people all around the world by enhancing crop production and providing innumerable benefits to society indirectly. Due to indiscriminate application of pesticide, it causes harmful impact on human health and environment pollution. However, farmers are unable to completely eliminate the hazards caused by the application of synthetic insecticides but by need-base utilization try to reduce it. Exposure to pesticides and hence the harmful consequences and undesirable effects of this exposure can be minimized by several means such as applied integrated pest management techniques. Through organic farming, the highly nutritive production of better, safe, and eco-friendly pesticide formulations can reduce the harmful effects.

8. Future scope

Now in the coming days, the chemical formulation can be utilized by a combination of biological and botanical products that give a positive impact on the sustainable reduction of pest population. This combination not only promises environmental sustainability, but also has diverse applications in controlling urban pests and invasive species. Pesticides have also posed a serious threat to the biological integrity of marine and aquatic ecosystems. It is the need of time to integrate the studies of different disciplines including toxicology, environmental chemistry, population biology, community ecology, conservation bioagents, and landscape ecology to understand the direct and indirect effects of pesticides on the environment.