Urban Pest Management: An Environmental Perspective

By Partho Dhang

The management and control of pests in the urban environment in the 21st Century faces many challenges. Pest populations adapt to changing conditions brought about by environmental changes caused by global warming, human population growth, and increased pollution. Urban pests are able to expand their ranges, densities, and habitats, sometimes causing large-scale damage and disease.

This book provides collective insights from academic and industry experts on perspectives concerning urban pest management and regulatory innovations arising from the rapid onset of recent environmental challenges. Chapter topics address pest biology, advances in urban pest management practices, emerging urban pest control developments, new technologies, and regulations.

The book describes new methods of pest control, their impacts on human health and the environment, and strategies for integrated management limiting the use of chemicals. It provides a practical resource for researchers and policy makers in pest management, urban health, medical entomology and environmental science. This title provides:

An up-to-date and comprehensive resource on environmental urban pest management.
A resource designed to appeal to pest control operators, public health professionals, and a range of field workers, as well as researching academics and graduate students.
Insights from both academic and industry experts together in one volume.

• Language: English
• Publisher: CAB International
• Release date: Aug 31, 2023
• ISBN: 9781800622944

Book preview

Introduction

Kevin Sweeney¹ and Partho Dhang²

¹Sweeney Consulting Group LLC, Crofton, Maryland, USA; ²Makati City, Philippines

Background

Environmental challenges are rapidly expanding in the 21st century. The primary causes appear to be human population growth, an abrupt migration of humans from rural to urban areas, a sudden rise in the mean global temperature, widespread pollution, and the slow actions of government and society to address these challenges collectively. Concurrently, pest populations (unlike their human counterparts) are rapidly adapting to these changes, and easily expanding their ranges, densities, and habitats with the help of human migration and transportation networks. Many pest species have invaded and established themselves in new areas without detection. Pest management professionals are in a reactive posture, scrambling for new detection and control methods to eliminate infestations while navigating the pesticide regulatory framework to gain approvals. From a global perspective, pesticides remain the primary means of controlling pests, but regulatory scrutiny of their use intensifies as precautionary principles are incorporated into national and international regulations. In response, Integrated Pest Management (IPM) practices combining technological advances have evolved rapidly, as described in this book.

Pests have followed the movement of humans from rural to urban areas, and the demand for urban pest management has never been greater than it is now. Climate change leading to increasing global temperatures coupled with human colonization of equatorial habitats provides additional species, often capable of transmitting vector-borne diseases, with an opportunity to become established in new and existing urban centers where vector control programs do not exist. Domestication of new pests rapidly develops with an ability to invade households and capitalize on new breeding and food sources made available by dense human habitation, waste and water disposal challenges, and porous construction practices. Urban pest management professionals have filled the gap to provide new community-level services in addition to their traditional residential and commercial work, but challenges remain.

This book provides critical environmental perspectives on approaches to urban pest management and regulatory insights arising from the rapid onset of recent environmental challenges, including climate change. Broadly speaking, chapter topics address pest biology, advances in urban pest management practices, emerging urban pest control developments, new technologies, and regulations. Topical discussions on chapter contents are introduced below.

The urban environment and health trends

Over 55% of the world’s population live in cities – a proportion expected to increase to 68% by 2050 (World Health Organization [WHO] 2022a, 2022b). As a result, public health, sanitation, and housing systems will be stressed to their maximum capacity – and in many instances, well beyond. These conditions will leave residents vulnerable to infectious diseases and likely affected by noncommunicable diseases resulting from local and global climatic changes. Unsanitary conditions, lack of adequate housing (WHO, 2018), overcrowding, and inadequate public services will provide all the elements necessary for explosive growth of urban pest populations. This will be accompanied by a shifting paradigm – expressed in terms of the pest bionomics of many species from sylvatic to domestic – in their habitat and behavior as the interface between the city and forest closes (Pereira Dos Santos et al., 2018). Formerly enzootic diseases may become urban public health challenges. The movement of disease vectors across continents and into cities will enhance this urban paradigm (Bonnefoy et al., 2008; WHO, 2022c) as humans and their traded goods are on the move to the cities.

Urban pest migratory patterns and movement ecology are supported by limited sets of data. Low- and high-migratory connectivity are concepts usually applied to birds. However, the migratory habits of some Lepidopteran and Odonatan species are understood (Gao et al., 2020). The impacts of migratory patterns leading to urban pest population isolation and its resulting effects on domestic behavior and food preferences are not known, but are likely to contribute to challenges for urban pest professionals and public health workers.

Partho Dhang in his opening chapter touches on some of the critical areas where changing environment will have an impact on urban pests and their management. This includes the impact from invasive and non-invasive species, expanding geographic ranges, and altered pest behaviors in the face of new environments. Environmental changes will also affect the quality of pest management and require new practices and technologies to meet emerging challenges. Pest management business practices will also need to adapt to counter the changes, as well as overcome possible restrictions due to climate and may soon have to include new control and surveillance tools, mobile-based information technology, additional applicator training and education, and community-level communications.

Use of pesticides remains the principal method for pest eradication and management. Urban pest resistance to pesticides is increasingly prevalent, while human occupational and residential pesticide exposures continue to be reported. Changes to urban environmental conditions resulting from climate changes and human migration to the cities may pose a greater risk of pesticide exposure, especially to children, while more sophisticated application methods will require applicator training to avoid occupational exposures. Environmentally sensitive methods based on IPM practices will need to evolve.

Further to this, pest resistance and cross-resistance to existing pesticides is reducing effectiveness of control measures, consequently requiring reapplications or overdosing, which profoundly decreases business profitability and increases residential exposure. For example, rodent control will become even more challenging as tools decline and rodents continue to develop and enhance behaviors capable of avoiding toxicants and control efforts. New York City is the most recent example of this challenge, as evidenced by the Norway rat populations. Insects including bed bugs, cockroaches, and mosquitoes are also developing behavioral avoidance to toxicant delivery systems, while quickly adapting to changing and enlarged urban environments.

Bed bugs have exploited resistance against insecticides and shown resurgence over the past two decades worldwide. Changlu Wang and Richard Cooper discuss this menacing pest, not just a nuisance but also a public health concern. They are one of the most challenging groups of urban pests facing pest management professionals, largely due to adaptation and cryptic behavior. In spite of underestimating the public health impact of the pest, which is not a vector, many control methods and tools have been developed for bed bugs. Nonchemical tools and techniques are essential in bed bug control as they are more reliable than most chemical methods and impose less environmental impact than pesticide-driven programs. The chapter discusses use of environmentally safer low-impact tools and methods, within an IPM approach to manage bed bugs.

One of the consequences of rapid urbanization is growth of urban chawls and makeshift housing. Multi-dwelling low-income housing, both private and public, in cities across the world is often considered to be the hot-bed for pest propagation and outbreaks. Sam Bryks, in his chapter, outlines existing bed bug and cockroach problems in such environments, which have not changed significantly. It is unfortunate that IPM is often mentioned as a feature of offered services – sometimes embellished by the term Green IPM, focusing on multiple methods. The actual service delivery is very often substandard and the management element of IPM is often totally missing in public and private housing, but especially in low-income housing. The reasons for this are multiple, including economics and education. The chapter thus focuses on illustrating key elements of IPM as well as addressing some critical issues of assessment of problems, treatment decision rules, and innovative practices.

Recent Technological Developments

As new pesticides take longer to come to market due to regulatory hurdles and higher developmental costs, technology must advance to make current pesticide applications more efficient and economical, while minimizing environmental impacts. A number of methods are discussed that increase effectiveness and specificity to meet societal expectations. Zia Siddiqi reviews important advances in education, communication, pest control data collection, analysis and business management systems, remote sensing and data technologies, advances in pesticide drift reduction technologies, non-chemical products, and service delivery methods, which are practical for urban IPM practitioners.

Insect baits, among other tools, have become popular in recent times as a stand-alone method to combat a number of important pests. Partho Dhang discusses food-based insecticide baits and their use as an environmentally sound treatment method. Baits are precise, do not smell or translocate, and do not leave stains or pollute, unlike conventional methods involving spray treatment. Since their commercialization, bait formulations have significantly improved the quality of pest control services and provided long-term control. However, the most significant improvement baits have brought to services is that it has allowed management of pests with negligible amounts of insecticide.

Rapid urbanization has seen termite protection grow into a significant business globally. This work uses an industry-formalized technique of injecting chemicals into soil to create a barrier. However, regular failures in preventing termite entry into buildings, in spite of using large volumes of chemicals, have stimulated research into more environmentally responsible methods of termite management. Over the past twenty years, this has led to considerable success in the use of bait technology to suppress and eliminate colonies of subterranean termites. Steven Broadbent discusses commercial development of termite baiting systems in Australia, which proves that bait technology can be used as a stand-alone method for protecting buildings. The degree of future protection provided is at least equal to, and probably better than, that provided by traditional toxic chemical soil barrier systems. Colony elimination rates and ongoing levels of property protection, as measured by lack of further termite damage, are considered to be 100% successful when programs are executed correctly. This has led to some baiting systems even providing consumer warranty programs to protect consumers against termite reinfestation.

As the search for new and safe molecules continues in the market place, technology that reduces occupational and environmental pesticide risks and exposures to existing molecules is advancing. Janusz Swietoslawski, Pawel Swietoslawski, David Liszka, and Aleksandra Gliniewicz discuss the advantage of encapsulation technology, which is being recognized worldwide as an effective means of delivering pesticides while reducing non-target impacts. This technology reduces all kinds of exposures. Encapsulation technology will continue to evolve to significantly influence critical formulation parameters that contribute to product formulation safety. Refinement of active ingredient release continues, leading to increasing longevity of treatments. The controlled release of the active substance aids in reducing the amount of active substance that needs to be applied for a treatment. Microencapsulation is significant for improving the efficacy of broadcast-surface and crack-and-crevice applications, thus reducing the need for retreatments. It is notable that research and development of microencapsulation technology is accelerating, based on the increasing number of patents granted globally.

Monitoring pests in IPM is a very significant step not only to design and keep check on control measures, but if used extensively can also reduce the pest population. In his chapter on insect light traps, Roberto Pereira elaborates how this tool provides an environmental solution to flying insects. Insect light traps are used to eliminate flying insect pests from facilities where insect presence is not tolerated. The traps work on the principle that flying insects can be attracted by different lights. Variations in color, light, and physical design allow for many types of insect light traps in the marketplace, designed for different pests.

Insects have been an integral problem to stored food grains throughout history, with the earliest evidence from archaeological deposits. The Montreal Protocol banning ozone-depleting gases, such as methyl bromide, has left the food industry with less effective tools for pest control. In his chapter, Nayem Hassan discusses the need to develop biorational pest management technologies for stored products, such as those using insect pheromones. The current use of pheromones of stored product insect pests as monitoring tools does not represent a direct alternative to chemical control, however pheromones are clearly an important component in decision-making methods, indicating that these and other methods could be applied in practice. This novel technology has been significantly refined in both science and delivery, and with continued research will no doubt be a major player in biorational pest control strategies for a large group of pests, including bed bugs.

In recent years, research has shown that the female bed bug produces an arresting pheromone that may also have an aggregating effect. Bed bugs are also attracted to natural compounds that are produced by human hosts, which collectively are a blend of kairomones. It has also been observed that bed bugs respond to a blend of (E)-2-hexenal and (E)-2-octenal causing a rapid running response to escape the point source – this would be considered an alarm pheromone (Benoit et al., 2009).

Pesticide Regulatory Trends

The pest management industry is always in a dilemma with the responsibility of protecting human health and property on one hand and the need to use more progressive strategies on the other. Progressive strategies include the judicious use of less toxic materials and environmentally compatible alternatives wherever applicable. In this scenario, pesticide regulation plays a vital role, acting as a safeguard. Pesticide regulation and risk assessment are thus trending towards more conservative global approaches to both evaluation and issuance of legal authority necessary to register and use these chemicals. Exposure assessments place increased emphasis on vulnerable populations. Consumers will expect not only precautionary approaches to regulatory assessment but greater oversight of pesticide application, sales, and service contracts, especially for cryptic pests such as termites and bed bugs. Kevin Sweeney discusses present and future regulatory perspectives on urban pest management. The chapter calls for a new regulatory paradigm during a time when the emergence and resurgence of urban pest problems and vector-borne diseases throughout the globe intensifies. In addition, precautionary principles based on pesticide product hazard need to be implemented through legislative mandates to regulatory systems, resulting in conservative approaches to pesticide risk and exposure assessments. Risks to vulnerable populations, such as children and the elderly, need to be emphasized where uncertainty exists. Also, pesticide developers and pesticide applicators must consider benefit assessment, together with research to support the continued use of pest control products and methods to offset the precautionary approaches to preserve existing pesticides and register new ones. The chapter stresses the need for modeling to describe pesticide benefits and quantitative means of measuring benefits. These are some new assessments that must be comparable to exposure and risk assessment in order to effectively weigh risks vs. benefits. Overall, urban pest management programs must continue sustainable practices that incorporate new technologies and strategies as part of evolving IPM programs to reduce risks in order to satisfy societal and regulatory requirements.

Steven Dwinell continues the subject of regulation and its need at consumer level as an essential part of a rational urban pest management system. Protection of the consumer from fraudulent or misleading practices, and practice by unlicensed or unregulated persons or companies, is considered necessary. Impartial third-party quality assurance agencies that review pest management practice in the context of food safety have a positive effect on ensuring effective urban pest management. It is suggested in the chapter that the maintenance of quality standards by third-party reviewers can effectively eliminate those pest management professionals who fail to adhere to good pest management practices or deliberately sacrifice effective pest control to pursue economic gain.

Future Epicenters of Vector-borne Diseases

Urban populations will be the most vulnerable to climate change (WHO, 2022a, 2022b). As cities grow rapidly into suburban areas, the likely lack of sanitary and water supply systems in new residential areas will lead to unsanitary conditions. Built housing will lag behind the influx of new residents. Unsanitary conditions combined with inadequate housing will provide opportunities for pest colonization and residential exposure to disease vectors, respectively. High density of human populations that can serve as hosts for blood-feeding vectors will result in disease transmission, most likely dengue, chikungunya, and zika in addition to already prevalent malaria.

Ana Eugênia de Carvalho Campos and Tamara Nunes Lima-Camara focus on some of the important pests and diseases associated with urban areas of Brazil, and discuss important public programs that are available for urban pest management together with control methods for vectors of tropical diseases. Brazil’s biodiversity reserves are the greatest in the world and its urban pests are similarly diverse. It is estimated that more than 80% of the country’s population live in urban areas, and urbanization processes and related services have been chaotic in many regions. Because of Brazil’s large area and with diverse pest populations – which include mosquitoes, sand flies, ants, termites, and rodents – pest management and public health professionals are challenged to provide adequate pest control for protection of human health. Vectors of tropical diseases are common and inadequate vector control means that the transmission of diseases such as malaria, yellow fever, dengue, Chagas disease and leishmaniasis is widespread.

Sand flies are of particular interest, as Huseyin Cetin and Yusuf Özbel describe in their chapter. Sand flies are vectors of 20 Leishmania protozoan parasites and more than 60 arboviruses that threaten animal and human health. Today, more than one billion people live in areas where leishmaniasis is endemic and are at risk of infection. These pests have traditionally been most threatening to public health in rural areas. However, much of their habitat may become colonized by urban populations and it remains to be seen if phenotypic selection pressures will result in intense urban disease transmission. Cultural and physical methods play a big role in managing sand fly populations as information on breeding sites is often limited due to difficulties of isolating the immature forms from the soil.

References

Benoit, J., Phillips, S., Croxall, T., Christensen, B., Yoder, J. and Denlinger, D. (2009) Addition of alarm pheromone components improves the effectiveness of desiccant dusts against Cimex lectularius. Journal of Medical Entomology 46, 572–579.

Bonnefoy, X., Kampen, H. and Sweeney, K. (2008) Public Health Significance of Urban Pests. World Health Organization Regional Office for Europe, Copenhagen. Available at: https://www.euro.who.int/__data/assets/pdf_file/0011/98426/E91435.pdf (accessed 16 December 2022).

Gao, B., Hedlund, J., Reynolds, D.R., Zhai, B., Hu, G. and Chapman, J.W. (2020) The ‘migratory connectivity’ concept, and its applicability to insect migrants. Movement Ecology 8, 48.

Pereira Dos Santos, T., Roiz, D., Santos de Abreu, F.V., Luz, S.L.B., Santalucia, M. et al. (2018) Potential of Aedes albopictus as a bridge vector for enzootic pathogens at the urban–forest interface in Brazil. Emerging Microbes & Infections 7, 191.

WHO (2018) WHO Housing and Health Guidelines. World Health Organization, Geneva, Switzerland. Available at: https://apps.who.int/iris/bitstream/handle/10665/276001/9789241550376-eng.pdf (accessed 16 December 2022).

WHO (2022a) Fact Sheet: Urban Health. World Health Organization, Geneva, Switzerland. Available at: https://www.who.int/news-room/fact-sheets/detail/urban-health (accessed 16 December 2022).

WHO (2022b) Health Topics: Urban Health. World Health Organization, Geneva, Switzerland. Available at: https://www.who.int/health-topics/urban-health#tab=tab_1 (accessed 16 December 2022).

WHO (2022c) WHO Initiative to Stop the Spread of Anopheles stephensi in Africa. World Health Organization, Geneva, Switzerland. Available at: https://www.who.int/publications/i/item/WHO-UCN-GMP-2022.06 (accessed 16 December 2022).

1 An Environmental Perspective on Urban Pests and Their Management

Partho Dhang*

Makati City, Philippines

*[e-mail]

© CAB International 2023. Urban Pest Management: An Environmental Perspective, 2nd Edition (ed. P. Dhang)

DOI: 10.1079/9781800622944.0001

Abstract

It is clear from current experiences that future challenges to managing pests will be determined more by the changing environment than any other factor. Concerns over the environment are at their highest and climate change, among other problems, has taken center stage. Evidence gathered highlights that the climate will have a significant effect on many factors in pest management, including invasion by non-native species, pest life history and behavior, pest redistribution, efficacy of pesticides, application techniques, exposure to pesticides, and pest control operations of practitioners involving their business and health.

Introduction

Concern regarding the environment is at its highest and climate change, among other things, has taken center stage. On the one hand, climate change has brought alterations in the bio-ecology of pests, and on the other it has put all human activities under close scrutiny, thus challenging the business of pest management as never before.

In addition to the shifting climate, use of pesticides – the principal means practiced for pest eradication and management – has not diminished over the years. Reports of exposure of humans to indoor pesticides are constant. According to a recent US Environment Protection Agency (US EPA) survey, 75% of US households used at least one pesticide product indoors during the past year. The most frequently used products are insecticides and disinfectants. Another study suggests that 80% of people’s exposure to pesticides occurs indoors and measurable levels of up to a dozen pesticides have been found in the air inside homes. The same survey revealed that the amount of pesticides found in homes appears to be greater than can be explained by recent pesticide use in those households, thus indicating the presence of pesticides in the near environment (US EPA, 2022).

This chapter discusses some critical areas where the changing environment will affect urban pests and their management.

Changing Environment and Invasion From Non-native Species

The impact of climate change on urban pests has been reviewed by Dhang (2016). Climate change can modify pest life history parameters, resulting in increased diversity and density of pests, consequently posing significant risk to humans. A number of reports have also discussed the effects of climate change on public health pests (WHO, 1997; Epstein, 2004; Mills, 2005; CIEH, 2008; US EPA, 2010). One aspect where climate change is most anticipated to have an impact is with regard to invasion by non-native species into areas where they were not previously recorded, or were rarely recorded. Such invasions are significant because regular checks are nonexistent, meaning that invading species have the opportunity to establish and cause harm quickly. However, there is considerable disagreement over which species these will be and the effects that each of them is likely to have (Comont, 2016).

It is thought that only a small subset of the non-native species introduced to a new area actually become established, and a yet smaller subset of these will go on to become invasive (Lodge, 1993). This is often referred to as the ‘tens rule’, whereby one species establishes from every ten introduced, and of every ten established species, one will become invasive, although the exact proportions are often variable (Vander Zanden, 2005). Climate suitability is one of the many factors influencing such invasions and the establishment and spread of non-native invertebrates (Smith et al., 2007). Consequently, very few non-native species are likely to arrive and arise as pests solely because of climate change (Comont, 2016). Therefore, the role of other factors, which include rapid urbanization, increased trade and travel, and socio-economic status of the region, become important in this phenomenon.

A UK report lists 282 non-native species as currently invasive in Great Britain, and these are estimated to have a direct cost of £1.7 billion per year. As this cost is largely related to control measures, an increase in pest species could lead to a considerable rise in the financial burden in the country (Comont, 2016). The same problem may arise elsewhere in the world.

Changing Environment and Pest Distribution

There is little disagreement that as species continue to move northwards with the warming of the climate, more species are likely to arrive and establish in temperate areas (Comont, 2016). Pests which could benefit and expand their distribution the most include mosquitoes, termites, rodents, and flies (Epstein, 2001), among others.

Evidence of climate change and its impact is now visible in many parts of the world, as confirmed in reports of insect vectors and vector-borne diseases in previously unrecorded elevations in eastern and central Africa, Latin America, and Asia. The rising incidence of malaria in highland urban centers such as Nairobi, rural highland areas, and Papua New Guinea (Reiter, 2008) is notable. Aedes aegypti, once limited by temperature to approximately 1000 meters in elevation, has recently been found at 1700 meters in Mexico and 2200 meters in the Colombian Andes (Epstein and Mills, 2005). A recent study in Ecuador found that Ae. aegypti will expand its range into higher elevations of the Andean foothills. This is estimated to affect 4215 km² of new territory and 12,000 people under the most extreme scenario of climate change by 2050 (Lippi et al., 2019).

Reports of tropical species, such as Coptotermes gestroi, becoming established in the subtropics (Grace, 2006) and subtropical species, such as Coptotermes formosanus, expanding their range northwards into more temperate areas (Jenkins et al., 2002) substantiate the role of climate change and urbanization in pest invasion by termites.

A recent study by Buczkowski and Bertelsmeier (2017) on invasive termites revealed that areas that lose many species (e.g. in parts of South America) are those that were previously species-rich. Regions such as Europe, which were not among the invasion hotspots, are now showing increases in invasive species. The researchers further concluded that the substantial economic and ecological damage caused by invasive termites is likely to increase in response to climate change, increased urbanization, and accelerating economic globalization, acting singly or interactively.

Changing Environment and Pest Behavior

Climate change can also initiate a number of behavioral changes in pest species. This is evident in mosquitoes, which have started exhibiting the capacity to breed in new habitats, including slurry pits, rainwater pools, and used car tires (CIEH, 2008), which could influence distribution patterns in a localized area. Behavioral changes and adaptation to changing environments could, triggered by climate change, play a role in species distribution as well. This is evident from the behavior of the Asian tiger mosquito Aedes albopictus, which out-competed the local population of Ae. aegypti in the United States. Ae. albopictus is adapted to breed in large numbers in nutrient-depleted water and shows tolerance to higher temperature, which helped it to displace Ae. aegypti (Juliano, 1998).

In addition, tools to manage pests will be challenged by the changing behavior of pests. It is reported that higher rearing temperatures increase pyrethroid resistance in adults of the Anopheles arabiensis SENN DDT strain, and increase pyrethroid tolerance in the An. arabiensis SENN strain. In addition, increasing temperature also significantly increases nitric oxide synthase (NOS) expression and decreases insecticide toxicity (Agyekum et al., 2021).

Temperature can also influence the effect of insecticides on mosquito larvae. Karen et al. (2012) examined the effects of increasing larval rearing temperatures on the resistance status of Trinidadian populations of Ae. aegypti to organophosphate (OP) insecticides. The study showed a positive association between resistance to OP insecticides and increased activities of α- and β-esterase in larval populations reared at 28 ± 2°C. Although larval populations reared at higher temperatures showed variations in resistance to OPs, there was a general increase in susceptibility. However, increases or decreases in activity levels of enzymes did not always correspond with an increase or decrease in the proportion of resistant individuals reared at higher temperatures (Polson et al., 2012).

It is thus evident that the population of mosquitoes could only be classified as susceptible or resistant to a given chemical depending on the temperature at which they were exposed. Glunt et al. (2014) showed in their research that lowering the exposure temperature from the laboratory standard 26°C strongly reduced the susceptibility of female An. stephensi to the World Health Organization (WHO) resistance-discriminating concentration of malathion. The susceptibility of these mosquitoes to the resistance-discriminating concentration of permethrin was not as strongly temperature-dependent. For permethrin especially, the thermal history of the mosquito was important in determining the ultimate survival outcome after insecticide exposure. This led the authors to conclude that investigations on the performance of insecticides under different temperature conditions is very important to better understand the epidemiological significance of insecticide resistance and to select the most effective products (Glunt et al., 2014).

Another unique phenomenon noted as a result of climate change is hybridization among invasive termite species. Chouvenc et al. (2015) observed that two invasive species, C. formosanus and C. gestroi, are hybridizing and producing hybrid colonies with twice the growth rate of incipient conspecific colonies. In parts of Florida, the dispersal flight season of the two species has begun to overlap due to changes in local climate. Mating pairs of heterospecific individuals were observed in the field, with C. gestroi males preferentially engaging in mating behavior with C. formosanus females. This leads to hybridization between the two species and the potential evolution of highly destructive ‘super-termites’ due to hybrid vigor (Buczkowski and Bertelsmeier, 2017).

Changing Environment and Quality of Pest Management

The efficacy of a pesticide is determined by its active ingredient. The active ingredient is usually mixed with other materials to make a formulation. Formulation improves the properties of the active ingredient and helps handling, storage, and application, and may substantially influence effectiveness and safety. However, various chemical and physical properties of an insecticide, such as stability, vaporization, penetration, activity, and degradation, are dependent on temperatures at the time of use. A report shows that the effect of insecticides is more rapid on insects at higher temperatures, although they do not always show a linear relationship with temperature (Uddin and Ara, 2006). Temperature has shown a positive effect on organochlorine, organophosphate, and carbamates in general, but has shown a negative effect on synthetic pyrethroids (Uddin and Ara, 2006; Wang and Shen, 2007).

The effects of temperature on the efficacy of insecticides on various pest species are available. Also, many of the studies have mentioned its relevance to climate change, particularly when used against vectors. Climate change could significantly affect the efficacy of insecticides and alter the result of a pest control activity because temperature will influence its storage, transportation, and application. The examples discussed below indicate that temperature has a significant synergetic influence on the efficacy of insecticides and should now be taken into account while planning a treatment.

Surface sprays using pyrethroid are a common method used for cockroach control and ambient temperature of the application area could influence the efficacy of the insecticide. Toxicity of DDT and pyrethrins when applied topically reduced with increasing temperature (Guthrie, 1950). The toxicity of two pyrethroid insecticides, S-bioallethrin and cypermethrin, was investigated over time at 12°C, 25 and 31°C in susceptible and kdr-resistant strains of Blattella germanica (L.) by Scott (1987). Both strains showed greater kill with decreasing temperature for S-bioallethrin. The susceptible strain had a negative temperature coefficient for knockdown but a positive temperature coefficient for mortality towards cypermethrin. The resistant strain had a negative temperature coefficient towards cypermethrin at all times. Resistance to S-bioallethrin was generally greatest at 25°C initially, although the difference between temperatures and the level of resistance diminished with time. Resistance to cypermethrin was significantly less at 12°C, than at 25°C or 31°C.

Insecticides are commonly used to control house flies. Khan and Akram (2014) showed a positive temperature coefficient with regard to toxicities of chlorpyrifos, profenofos, and emamectin in a temperature regime of 20–34°C, whereas the toxicities of cypermethrin, deltamethrin, and spinosad decreased, showing a negative temperature coefficient.

Termiticides have been the mainstay for controlling termites and are applied to the soil. Termiticide performance is dependent on a number of soil parameters, predominantly soil properties such as moisture and temperature (Kamble, 2006). Wiltz (2012) highlighted the importance of temperature, among other factors, on the efficacy of soil termiticides and showed that soil temperature affects termiticide bioavailability through its influence on solubility and adsorption. Temperature also has an effect on the physical and chemical properties of the pesticide and the rate of microbial degradation. Several studies have demonstrated that temperature affects adsorption of pesticides to soil, but that the nature of this effect varies among pesticides. In general, termiticides will remain more efficacious and persistent in soils with low temperatures and low moisture content. Warm soil temperatures and moist conditions can enhance the activity of insecticide-degrading microorganisms, thereby increasing degradation of the compound (Kamble, 2006).

Changing Environment and Exposure to Pesticides

Pest management has become a necessity for humans due to their choice to live in urban areas. Consequently, human dependence on pesticide use indoors has not diminished. In spite of efforts to reduce pesticide use through education, regulation, and alternative technologies,