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Biological pest control

Biological pest control

Introduction to Biological Pest Control

Definition of Biological Pest Control

Biological pest control, also known as biocontrol, is a method that employs living organisms to manage and reduce the population density of pests. This approach is grounded in the natural control mechanisms that exist within ecosystems, where organisms are consumed by other organisms, often leading to significant reductions in the population of the prey species. Biological control harnesses this 'natural control' to suppress pest species, aiming to maintain them at low densities rather than eradicating them entirely. This method is a fundamental component of integrated pest management (IPM), which combines various strategies such as resistant plants, cultural techniques, physical barriers, semiochemicals, and selective chemicals to control pests effectively and sustainably.

There are different categories of biological pest control, each with distinct characteristics and applications. Natural biological control refers to the ecosystem service provided by resident natural enemies of pests and pathogens, contributing to the regulation of pest populations without human intervention. Conservation biological control, on the other hand, involves human stimulation of resident natural enemies to enhance their control of pests, while augmentative biological control refers to the addition of mass-reared biocontrol agents to temporarily augment their population densities in a targeted area. Classical biological control denotes the addition of new biocontrol agents for proliferation and long-term establishment, playing a significant role in managing pests on a larger scale.

Biological pest control has been practiced for over a century and has been applied to various types of pests, including insects, pathogens, weeds, and rodents, in both terrestrial and aquatic ecosystems. Its significance extends beyond pest management, as it also contributes to the preservation of ecosystem functions and services, with an estimated minimum value of 400 billion US$ per year, far exceeding the annual expenditure on insecticides. Despite its potential, biological pest control faces challenges related to fragmentation into sub-disciplines and the need for a unified terminology and conceptual framework that can be accepted across all areas of biological control research and practice.

Importance of Biological Pest Control

The importance of biological pest control lies in its potential to provide a sustainable and environmentally friendly solution to managing pests in agriculture and other ecosystems. Biological control, or biocontrol, is the use of living organisms to suppress pest populations, making them less damaging than they would otherwise be. This approach has several advantages over traditional pesticide use, including reduced environmental impact, lower risk of pest resistance, and potential cost savings in the long term.

One of the key benefits of biocontrol is its minimal impact on non-target organisms and the environment. Unlike chemical pesticides, which can indiscriminately kill a wide range of insects and other organisms, biocontrol agents are typically highly specific to their target pests. This specificity reduces the risk of harm to beneficial insects, such as pollinators, and other non-target organisms. Additionally, biocontrol agents often reproduce and persist in the environment, providing long-term suppression of pest populations and reducing the need for repeated applications of control measures.

Another advantage of biocontrol is the lower risk of pest resistance. Pesticide resistance is a significant concern in modern agriculture, as pests can evolve resistance to chemicals, rendering them ineffective over time. In contrast, biocontrol agents often have multiple modes of action, making it more difficult for pests to develop resistance. Furthermore, the use of multiple biocontrol agents with different modes of action can further reduce the risk of resistance development.

Biological control can also be more cost-effective than traditional pesticide use in the long term. While the initial costs of developing and implementing a biocontrol program can be high, the ongoing costs of maintaining the program can be lower than the costs of repeated pesticide applications. Additionally, biocontrol can help maintain ecosystem services, such as pollination and natural pest control, which can have significant economic value.

However, biocontrol is not without its challenges. The success of biocontrol programs can be influenced by various factors, including the composition of the surrounding landscape, the specific pest-natural enemy system, and environmental conditions. Careful consideration of these factors is necessary to ensure the effectiveness of biocontrol programs. Additionally, the commercialization and availability of biopesticides can be hindered by issues such as the availability of plant sources, formulation challenges, and the biodegradability of biological pesticides.

In conclusion, biological pest control is a crucial component of sustainable agriculture and ecosystem management. Its minimal environmental impact, lower risk of pest resistance, and potential cost savings make it an attractive alternative to traditional pesticide use. However, careful consideration of the factors influencing biocontrol success is necessary to ensure effective and sustainable pest management.

Types of Biological Pest Control

Predators

Predators are a crucial component of biological pest control. They are insects and mites that feed on pests but do not reproduce in them. Predators consume more than one pest throughout their life cycle to adults, making them less host-specific than parasitoids. Predators are essential in reducing pest populations and are used in greenhouse production as part of an integrated pest management program (IPM).

There are various commercially available predators for controlling different pests. For instance, parasites such as Dacnusa sibirica and Diglyphus isaea are used for controlling leafminers (Liriomyza spp.). These parasitoids are most effective for long-term crops such as cut flowers and stock plants and should be used for mealybugs (mainly citrus mealybug, Planococcus citri, and longtailed mealybug Pseudococcus adonidum). It is important to identify mealybugs to species before releasing natural enemies. The parasitoid Leptomastix dactylopii is only effective for citrus mealybug. The predatory ladybird beetle Cryptolaemus montrouzieri is also used to control citrus mealybug, but is less effective for longtailed mealybug.

Biological control of armored and soft scales may be difficult due to the wide range of scale species that may occur. Currently, the number of commercially available natural enemies for control of both armored and soft scale is limited. Chrysoperla spp. (green lacewing) and Rhyzobius lophanthae are two commercially available predators. Bacillus thuringiensis spp. kurstaki (Bt) is available that provides satisfactory control for some kinds of caterpillars. Bt is a bacterium that must be consumed by the caterpillar to be effective and causes the caterpillar to stop feeding within 24-48 hours after eating the bacterium and die after 3-4 days.

Incorporating biological control into pest management systems can reduce reliance on pesticides, decrease potential for development of pesticide resistance, and provide reputational benefits for being a sustainable and responsible grower or professional. Biological control can also be used to manage pest populations that have developed pesticide resistance. The use of natural enemies or agents in biological control can suppress pest population and damage without pesticide or with reduced pesticide, making it an environmentally safe, energy self-sufficient, cost-effective, sustainable, and readily incorporated into IPM programs.

Parasitoids

Parasitoids are a crucial component of biological pest control strategies, particularly in greenhouse crops. They are a specific type of natural enemy that, upon hatching, kill their host, making them highly effective in controlling pest populations. Parasitoids can be categorized into two groups: idiobionts and koinobionts. Idiobionts kill their host during the parasitoid's development, while koinobionts allow the host to continue developing, often with detrimental effects on the host's growth and reproduction.

The interaction between parasitoids and entomopathogens, such as fungi, bacteria, and viruses, can have varying effects on pest control. While some studies have reported negative impacts of entomopathogens on parasitism rates, others have shown positive effects. The compatibility of these biocontrol agents is influenced by several factors, including the type of microorganism, the parasitoid species, and the host insect.

Banker plant systems, which involve the use of non-pest insects to support the development of parasitoids, have been successfully implemented in greenhouse crops. These systems allow parasitoids to reproduce and establish populations before the arrival of pests, enhancing the effectiveness of biological control strategies. However, the success of banker plant systems depends on various factors, such as the size and nutritional value of the provided aphids, which can impact the survival and sex ratio of the parasitoids.

In conclusion, parasitoids are a vital component of biological pest control, particularly in greenhouse crops. Their interaction with entomopathogens and the use of banker plant systems can significantly influence the efficacy of biological control strategies. Further research is needed to optimize these interactions and improve the compatibility of different biocontrol agents for enhanced pest control.

Pathogens

Pathogens are micro-organisms that can cause diseases in insects, plants, and animals, including humans. They include bacteria, fungi, and viruses, which are relatively host-specific and can kill or debilitate their hosts. In the context of biological pest control, pathogens can be used as biological pesticides to control pests and diseases. For example, the bacterium Bacillus thuringiensis is widely used against Lepidopteran (moth, butterfly), Coleopteran (beetle), and Dipteran (true fly) insect pests. The bacterium produces proteins that are toxic to insect pests, and when sprayed onto vulnerable plants, it can reduce the necessity for pesticide use. However, if pests develop resistance to the toxins in these crops, B. thuringiensis will become useless in organic farming also.

The use of pathogens against aquatic weeds was unknown until a groundbreaking 1972 proposal by Zettler and Freeman. Up to that point, biocontrol of any kind had not been used against any water weeds. In their review of the possibilities, they noted the lack of interest and information thus far and listed what was known of pests-of-pests – whether pathogens or not. They proposed that this should be relatively straightforward to apply in the same way as other biocontrols. And indeed, in the decades since, the same biocontrol methods that are routine on land have become common in the water.

The use of pathogens as biological pesticides has several advantages over chemical pesticides. They are host-specific, which means they are less likely to harm non-target organisms. They are also self-sustaining, which means that once established, populations are self-sustaining, and they can reduce the use of conventional pesticides. However, the use of pathogens as biological pesticides also has some limitations. They are relatively slow-acting, and they may not be effective against all pests and diseases. Moreover, the development of resistance to pathogens is a concern, as it has been observed in some pests and diseases. Therefore, it is essential to use pathogens as part of an integrated pest management (IPM) program, which includes cultural, physical, and chemical methods of pest control.

In summary, pathogens are micro-organisms that can cause diseases in insects, plants, and animals. They can be used as biological pesticides to control pests and diseases in the context of biological pest control. The use of pathogens as biological pesticides has several advantages over chemical pesticides, such as host-specificity and self-sustainability. However, it also has some limitations, such as slow-acting and the development of resistance. Therefore, it is essential to use pathogens as part of an integrated pest management (IPM) program to achieve effective and sustainable pest control.

Advantages and Disadvantages of Biological Pest Control

Pros of Biological Pest Control

Biological pest control offers several advantages over traditional chemical pesticides. Firstly, it is a more environmentally friendly approach, as it relies on natural enemies of pests, such as predators, parasites, pathogens, and competitors, to control pest populations. This minimizes the risk of harmful residues in the environment, as well as the potential for groundwater contamination and the development of pesticide-resistant pest strains.

Secondly, biological control is often more specific to the target pest, reducing the impact on non-target organisms, including beneficial insects and other wildlife. This specificity can lead to increased selectivity, as the host-parasite or prey-predator relationship usually does not affect other organisms. This is particularly important in agricultural settings, where maintaining biodiversity and ecosystem health is crucial.

Thirdly, biological control can be more cost-effective in the long term, especially when applied to low-level pest populations. While the initial costs of studying, choosing, testing, and breeding a bioagent may be high, the long-term control of pests can be inexpensive, as bioagents can act over several generations to manage pest populations.

Lastly, biological control can be integrated with other pest management strategies, such as cultural, mechanical, and chemical controls, to create a comprehensive and sustainable pest management plan. This integrated approach can help to minimize the reliance on chemical pesticides, while still maintaining effective pest control.

In conclusion, biological pest control offers numerous advantages over traditional chemical pesticides, including reduced environmental impact, increased selectivity, long-term cost-effectiveness, and the potential for integration with other pest management strategies. However, it is important to note that biological control requires careful planning, management, and understanding of the biology of the pest and its enemies to be successful.

Cons of Biological Pest Control

While biological pest control offers numerous environmental benefits, there are also some disadvantages to consider. One of the main concerns is the limited control over natural enemies, which may move away or not completely destroy pests. This can result in incomplete pest control and some damage to crops. Additionally, the establishment of natural enemies can take time, making it difficult to use biological control before pests have occurred.

Another disadvantage is the potential harm to non-target organisms. Although biological control agents are generally harmless to the environment, they can still affect other organisms that are not targeted. This can have unintended consequences on the agricultural ecosystem, potentially leading to a decrease in the population of beneficial species.

Furthermore, the effectiveness of biological control can be influenced by various factors, such as weather conditions and the stage of crop development. This can make it difficult to achieve consistent results, particularly in large-scale agricultural operations.

Lastly, the cost of biological control can be a significant factor. While it may provide long-term benefits, the initial investment can be high, and there may be additional costs associated with maintaining the natural enemies. This can be a barrier for some farmers, particularly those with limited resources.

In summary, while biological pest control offers many advantages, it is important to consider the potential disadvantages. These include limited control over natural enemies, potential harm to non-target organisms, variable effectiveness, and high costs. Addressing these challenges will be crucial for the widespread adoption of biological pest control in agriculture.

Implementation of Biological Pest Control

Steps in Implementing Biological Pest Control

Implementing Biological Pest Control involves several steps and considerations. The primary goal of biological pest control is to suppress pest populations and damage without pesticides or with reduced pesticide usage. This can be achieved through three general approaches: Classical Biological Control, Augmentative Biological Control, and Conservation Biological Control.

Classical Biological Control, also known as importation, involves the introduction of natural enemy species from the pest's area of origin to establish a long-term population that manages the pest. This method is typically conducted by scientists at governmental agencies or universities, and the practical application by growers, professionals, and consumers is minimal. An example of successful classical biological control is the use of decapitating flies and a group of flea beetles, thrips, and stem borers against alligator weed.

Augmentative Biological Control, on the other hand, involves the periodic release of mass-reared natural enemies to supplement or flood pest populations with natural enemies. This method is commercially deployed in various cropping systems worldwide and can be achieved through inundative or inoculative releases. Inundative releases involve the release of large numbers of biological control agents to quickly overwhelm the pest population, while inoculative releases involve the release of smaller numbers of agents to establish a population that provides long-term and sustained control.

Conservation Biological Control focuses on manipulating the habitat, plant diversity, production practices, and pest management practices to increase the population and effectiveness of natural enemies. This approach often starts with manipulating the farmscape or landscape, such as growing insectary plants that attract and retain natural enemies or provide them with food and shelter.

When implementing biological pest control, it is essential to consider the target pest, host, environmental conditions, and pest life cycle. Accurate identification of the pest species is crucial for selecting the correct natural enemy species for augmentative biological control. Additionally, the efficacy of a classical biological control program depends on the newly released parasitoids successfully establishing populations that can compete in the new environment.

In summary, implementing biological pest control requires a comprehensive understanding of the ecology and behavior of pests and their natural enemies, as well as careful consideration of the target pest, host, environmental conditions, and pest life cycle. By utilizing the three general approaches of Classical Biological Control, Augmentative Biological Control, and Conservation Biological Control, growers and professionals can reduce reliance on pesticides, decrease potential for development of pesticide resistance, and promote sustainable and responsible pest management practices.

Factors to Consider when Implementing Biological Pest Control

When implementing biological pest control, several factors must be taken into account to ensure its success. These factors include the environmental conditions, the traits of the species involved, and the integration of biological control into existing pest management systems.

Firstly, the environmental conditions play a crucial role in the effectiveness of biological control. Factors such as temperature, humidity, and the availability of resources can significantly impact the survival and reproduction of the natural enemies used for pest control. For example, the success of the fungus Entomophaga maimaiga in controlling gypsy moth populations is highly dependent on temperature and humidity conditions.

Secondly, the traits of the species involved, both the pest and the natural enemy, are essential factors to consider. The natural enemy's ability to locate, attack, and kill the pest, as well as its ability to reproduce and survive in the environment, are critical for successful biological control. Similarly, the pest's susceptibility to the natural enemy and its ability to develop resistance are also important considerations.

Lastly, the integration of biological control into existing pest management systems is crucial for its long-term success. This includes the conservation of existing natural enemies, the introduction of new natural enemies, and the mass rearing and periodic release of natural enemies. The use of integrated pest management (IPM) approaches that combine biological, cultural, and chemical control methods can also enhance the effectiveness of biological control.

In addition, the composition of the surrounding landscape can significantly impact the effectiveness of biological control. Research has shown that the effectiveness of augmentative biocontrol to manage agricultural pests in field situations depends strongly on the composition of the surrounding landscape. For example, augmentative biocontrol was more effective in suppressing lepidopteran pests in complex than in simple landscapes.

Furthermore, cognition in natural pest predators could be used to increase prey specificity, making predators more efficient in their service provisioning. Prey specificity in natural enemies is context-specific, and influencing prey specificity presents scope to adapt predator behavior to make predators more efficient in their service provisioning.

In conclusion, several factors must be considered when implementing biological pest control, including environmental conditions, the traits of the species involved, and the integration of biological control into existing pest management systems. The composition of the surrounding landscape and cognition in natural pest predators are also important considerations for successful biological pest control.

Case Studies of Biological Pest Control

Biological Pest Control in Agriculture

Biological pest control in agriculture is a crucial aspect of integrated pest management (IPM) strategies, which aim to reduce the use of synthetic pesticides and minimize their negative environmental impacts. Biological control, or biocontrol, involves the use of natural enemies such as predators, parasites, pathogens, and competitors to manage pest populations. This approach leverages the ecological relationships between pests and their natural enemies to maintain pest populations below economic injury levels.

In agricultural settings, biocontrol can be achieved through various methods, including classical, conservation, and augmentative biological control. Classical biological control involves the introduction of natural enemies from the pest's native range to establish long-term control. Conservation biological control, on the other hand, focuses on enhancing and protecting the habitats of existing natural enemies to promote their effectiveness. Augmentative biological control involves the periodic release of natural enemies to supplement the existing population and provide immediate control.

One successful example of biocontrol in agriculture is the use of the parasitic wasp, Trichogramma, to control the European corn borer in maize crops. Trichogramma wasps lay their eggs inside the eggs of the corn borer, killing the pest before it can hatch. This method has been widely adopted in the United States and Europe, resulting in significant reductions in pesticide use and increased crop yields.

Another example is the use of the bacterium, Bacillus thuringiensis (Bt), to control caterpillar pests in crops. Bt produces a crystalline protein that is toxic to certain insects when ingested. When sprayed on crops, it targets specific pests while leaving beneficial insects unharmed. Bt has been used successfully in the control of the cotton bollworm, tobacco budworm, and European corn borer.

Biological pest control in agriculture offers numerous benefits, including reduced reliance on synthetic pesticides, decreased environmental pollution, increased biodiversity, and improved food safety. However, it is not without its challenges. Biocontrol agents may not always provide complete control, and their effectiveness can be influenced by various factors such as climate, crop stage, and pest density. Therefore, a comprehensive IPM approach that combines biocontrol with other management strategies is essential for sustainable pest control in agriculture.

Biological Pest Control in Gardens

Biological pest control in gardens is an effective and environmentally friendly method of managing pests that can cause damage to plants and reduce crop yields. This approach involves using natural enemies of pests, such as predators, parasites, pathogens, and competitors, to control pest populations. By harnessing the power of nature, gardeners can maintain a healthy and balanced ecosystem in their gardens, reducing the need for chemical pesticides that can harm beneficial insects and other wildlife.

One of the most common methods of biological pest control in gardens is the use of predator insects. Ladybugs, for example, are natural predators of aphids, scale insects, and mealybugs, and can consume hundreds of these pests during their lifetime. Lacewings and minute pirate bugs are also effective predators of various soft-bodied pests. By introducing these beneficial insects into the garden, gardeners can help to keep pest populations in check and promote healthy plant growth.

Another effective method of biological pest control in gardens is the use of parasitic wasps. These wasps lay their eggs inside or on the bodies of host insects, and the developing larvae feed on the host, eventually killing it. Parasitic wasps are effective against a wide range of pests, including aphids, whiteflies, and caterpillars. By releasing these wasps into the garden, gardeners can help to reduce pest populations and promote healthy plant growth.

In addition to using predator insects and parasitic wasps, gardeners can also use pathogens to control pests. Bacteria, fungi, and viruses can all be used to kill or inhibit the growth of pests. For example, Bacillus thuringiensis (Bt) is a bacterium that produces a toxin that is deadly to caterpillars and other leaf-feeding insects. By spraying Bt onto plants, gardeners can protect them from damage caused by these pests.

Overall, biological pest control in gardens is a safe and effective way to manage pests without relying on chemical pesticides. By using natural enemies of pests, gardeners can promote a healthy and balanced ecosystem in their gardens, while also protecting beneficial insects and other wildlife. As with any pest control method, it is important to monitor pest populations regularly and adjust control strategies as needed to ensure optimal results.

Future Perspectives of Biological Pest Control

Technological Advancements in Biological Pest Control

Technological advancements have significantly enhanced the effectiveness and precision of biological pest control methods. DNA sequencing and amplification technologies have been used to identify and monitor pests, enabling the detection of specific organisms based on short DNA sequences. This technology has been integrated into automated systems for remote pest detection, providing real-time information to growers for timely pesticide application.

The development of biopesticides, which are derived from natural sources, has also been a significant advancement in biological pest control. Biopesticides are non-toxic and do not harm the environment or non-target organisms, making them an eco-friendly alternative to conventional pesticides. In addition, recent studies have shown that microbe-pesticide interactions can promote plant growth and increase crop yield, further enhancing the benefits of biological pest control methods.

Artificial intelligence (AI) has also shown great promise in transforming the pest control industry. AI systems can analyze large amounts of data to identify patterns and trends, enabling more accurate predictions of pest occurrences and reducing costs. AI-powered pest control solutions, such as AI-powered cameras and AI-driven pesticides and pheromone traps, have been developed to detect and identify pests more efficiently and effectively.

Integrated pest management (IPM) emphasizes a sustainable long-term approach to pest control by combining biological, cultural, physical, and chemical tools to minimize economic, health, and environmental risks. IPM programs favor non-chemical methods to control pests and use pesticides sparingly, making them an environmentally friendly and sustainable approach to pest control.

In conclusion, technological advancements in biological pest control have significantly enhanced the effectiveness and sustainability of pest control methods. DNA sequencing and amplification technologies, biopesticides, AI, and IPM are just a few examples of the innovative solutions that have been developed to address the challenges of pest control. These advancements have not only improved pest control but have also promoted environmental sustainability and reduced costs.

Sustainability of Biological Pest Control

Sustainability of Biological Pest Control

Biological pest control has emerged as a promising approach to manage pests while minimizing the negative environmental impacts associated with traditional pesticide use. The sustainability of biological pest control relies on various factors, including the understanding of the ecological dynamics of pests and their natural enemies, the development of effective mass rearing and delivery methods, and the integration of biological control agents within the broader framework of Integrated Pest Management (IPM).

One of the key aspects of sustainable biological pest control is the optimization of predatory insects, parasitoids, and microbial pathogens as biological control agents (BCAs). Research on mass rearing, formulation, and application methods is encouraged to enhance the effectiveness of these natural enemies. The augmentation and conservation of natural enemies through releases and habitat management play a crucial role in promoting ecological conservation and enhancing the habitats of beneficial insects.

Microbiome-mediated control offers another promising avenue for sustainable pest management. By exploring microbiome interactions, researchers aim to improve pest management and plant health, thereby fostering plant resilience against pests. Climate-resilient strategies that address the impact of climate change on pest dynamics and develop adaptive control strategies are also essential for the long-term sustainability of biological pest control.

Policy and socio-economic implications significantly influence the adoption of biological control strategies by farmers. Discussing policy recommendations, economic incentives, and socio-cultural factors is vital for promoting the widespread use of biological control methods. By integrating these elements into the development and implementation of biological pest control, it is possible to achieve sustainable agriculture that balances crop protection with ecological conservation.

In summary, the sustainability of biological pest control hinges on various factors, including the optimization of BCAs, habitat enhancement, microbiome-mediated control, climate-resilient strategies, and policy and socio-economic considerations. By addressing these aspects, biological pest control can contribute significantly to sustainable agriculture, minimizing the negative environmental impacts associated with traditional pesticide use.

Biological pest control FAQ

What is an example of biological control of pests?

Biological control, also known as biocontrol, is a method of controlling pests using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically involves an active human management role. Biological control can be an important component of integrated pest management (IPM) programs.

There are three basic strategies for biological control: classical (importation), inductive (augmentation), and inoculative (conservation). Classical biological control, or importation, involves the introduction of a pest's natural enemies to a new locale where they do not occur naturally. This strategy has been successful in controlling various pests, such as the cottony cushion scale in Australia using the vedalia beetle, and the alfalfa weevil in the United States using natural enemies.

An example of biological control is the use of decapitating flies (several Pseudacteon species) against red imported fire ants, and a group of flea beetles, thrips, and stem borers used against alligator weed. These natural enemies help control the pests, reducing the need for chemical pesticides and their potential environmental impacts.

Biological control offers significant social, environmental, and economic advantages. It can become self-sustaining and integrated in the normal environment of the control area, providing long-term control at a potentially low total cost. Biological control is particularly useful where chemical pesticides are not suitable or are impractical, such as in low-unit-value crops like alfalfa or soybeans, where complete control may not be required.

In summary, biological control is a valuable tool in managing pests by using other organisms to control their populations. It offers various benefits, including reduced reliance on chemical pesticides, long-term control, and environmental protection. Classical biological control, or importation, is one strategy that has been successful in controlling various pests.

What is biological method for pest control?

Biological method for pest control, also known as biocontrol, involves the reduction of pest populations through the use of natural enemies such as parasitoids, predators, pathogens, antagonists, or competitors. This method is easy and safe to use, cost-effective, environmentally sound, reduces the use of conventional pesticides, and can be implemented as part of an Integrated Pest Management (IPM) program. Once established, populations of biological control agents are self-sustaining and target specific.

There are three general approaches to biological control: classical, augmentative, and conservation.

  1. Classical Biological Control: This approach involves the introduction of one or a group of natural enemy species of foreign origin to control invasive pests. These natural enemies are often found in the home range of the invasive pest and are subjected to extensive testing, quarantining, and rearing before introduction. Classical biological control programs are typically conducted by scientists at governmental agencies or universities.

  2. Augmentative Biological Control: This method involves the release of biological control agents, often mass-reared in insectaries, to increase the number or effectiveness of natural enemies in an area. This approach is most often practiced in greenhouses, nurseries, and some fruit and vegetable fields. The mass-produced biological control agents are purchased from suppliers and released/applied en masse into the infested area.

  3. Conservation Biological Control: This approach involves manipulating the habitat, plant diversity, production practice, and pest management practice to increase the population and effectiveness of natural enemies. Growing insectary plants, minimizing impacts of habitat manipulation or farming practices on natural enemies, and providing shelters for ground beetles are examples of conservation biological control practices.

Biological control has been successful in controlling various pests, such as the alien yellow starthistle in the USA, which has been controlled by insect natural enemies such as Bangasternus orientalis, Eusternopus villosus, Urophora sirunaseva, and Chaetorellia succinea that attack the seed head.

Grower education plays a crucial role in the adoption of biological pest control measures. Growers may prefer to stay with the familiar use of pesticides, but pesticides have undesired effects, including the development of resistance among pests and the destruction of natural enemies. One method of increasing grower adoption of biocontrol methods involves letting them learn by doing, for example, showing them simple field experiments, enabling them to observe the live predation of pests, or demonstrations of parasitised pests.

What is the downside to biological pest control?

Biological pest control, while offering many benefits such as reduced environmental impact and lower risk to non-target organisms, does have its downsides. One major concern is the potential for pests to develop resistance to biological control agents. Over time, pests may adapt to the presence of these control methods, rendering them ineffective. This can lead to a cycle of reinfestation and the need for increasingly stronger or more frequent applications of biological control agents, which can ultimately become cost-prohibitive and potentially harmful to the environment.

Another challenge with biological pest control is the difficulty in achieving a consistent level of control. Factors such as weather, soil conditions, and the presence of other pests or diseases can all impact the effectiveness of biological control agents. This can make it challenging to predict and manage pest populations, leading to unpredictable results and potential crop damage.

Finally, biological pest control may not be as fast-acting as chemical pesticides, which can be a drawback in situations where immediate control is necessary. However, it is important to note that while chemical pesticides may provide faster results, they also come with significant environmental and health risks, making biological control methods a more sustainable and responsible choice in the long term.

How much does biological control cost?

Biological control, or biocontrol, is a method of pest control that uses living organisms to suppress pest populations, making them less damaging than they would otherwise be. This approach has been shown to offer significant social, environmental, and economic advantages, and can become self-sustaining and integrated into the normal environment of the control area.

The cost of biocontrol varies depending on the specific approach used. There are three main types of biological control: conservation, classical, and augmentative. Conservation involves maintaining and enhancing existing natural enemies, while classical biological control involves introducing new natural enemies to establish a permanent population. Augmentative biological control involves mass rearing and periodic release of natural enemies, either on a seasonal basis or inundatively.

In the case of classical biological control, the process of finding, collecting, and evaluating natural enemies in a pest's native area, followed by their rearing, release, and post-release monitoring, can take several years and involve significant costs. However, the long-term benefits of biocontrol can outweigh the initial expenses. For example, in 1987, USDA calculated that nationally, biological controls against the alfalfa weevil netted savings of about $48 million annually, with research costs of $1 million, resulting in a return on investment of about 50 to 1.

In the context of integrated pest management (IPM) programs, biocontrol is often used in combination with other pest management strategies, such as cultural, physical, and chemical methods. The choice of which biological control agents to use depends on various factors, including the pest's biology, the environment, and the specific goals of the control program.

In summary, while the cost of biocontrol can be high, especially in the case of classical biological control, the long-term benefits, such as reduced pesticide use, increased biodiversity, and improved environmental quality, can make it a cost-effective and sustainable approach to pest management.