What Are Biocontrol Agents Definition Types Mechanism and Examples
Biocontrol can be defined as the control of the type of living organisms with the application of another. The use of Biocontrol agents are also called biological control and are mainly used for the reduction of pest population and produce yields that are free of any pests. The biocontrol methods are a long-term method and most importantly, a self-sustaining one that helps in the control of invasive species of plants. Weed infestation and pests are controlled with the help of insects, pathogens, and grazing animals. The natural animals in the form of parasitism, predation along with other similar mechanisms perform the role of biocontrol agents which help in maintaining the balance.
Types Of Biocontrol Agents
Natural biological control can be done using two primary methods. Inundative Biocontrol makes use of pathogens. This approach makes use of pathogens that help to control the growth of weeds and is as effective as herbicides. Nematodes and nuts are most commonly used in inundative biological control and prevent invasive plants from implementation. Classical Biocontrol is another process that helps in the organic method of pest control. This method of Biocontrol makes use of the natural prey-predator relationship. In classical Biocontrol, an eternal relationship is formed between plants and biological control animals.
Different Biological Control Agents
Biological control agents' examples are given below:
Fungi
Fungus, as a biocontrol method, forms a biological method of pest control. Fungi as a biocontrol method are considered a rapidly developing method and do not cause any harm to the environment. Fungi as a biocontrol method have proved to be a very effective alternative to chemical pesticides. Fungi as a biocontrol method are gaining widespread popularity in recent times. Entomophaga is a form of fungi that is effective against green peach aphids that forms a biological method of pest control.
Predators
Predators are mainly free-living organisms that consume other animals in a large number of prey in the span of their lives. Considering insects are majorly consumed crops, the ideal predators to act as a biological method of pest control are spiders, dragonflies, lacewings, etc.
Bacteria
The bacteria which belong to the genus coccobacillus are comparatively more pathogenic to insects and hence used for biological control. The bacteria infect insect's digestive tracts which limit the options for insects that have sucking mouthparts. Bacteria form a biological method of pest control.
Virus
The creation of a virus which would selectively target pests and act as biological control is still under scientific research. These viruses would be specific regarding their hosts and would hence be effective biocontrol agents.
Parasitoids
The parasitoids lay eggs in the body of their hosts which ultimately leads to the death of the host. The dead host is then used by the larvae as a food source as is one of the most prevalent methods of biological control.
Advantages and Disadvantages Of Biological Control
The advantages of biological control ecology and applications are plenty. The biological control agents are environmentally friendly and do not have any side effects for humans. These methods are also comparatively cheaper than other Agrochemicals like pesticides and insecticides. These methods are also easy to use, readily available, and can be used in any season throughout the year. The most crucial use of biocontrol agents is perhaps they help in reducing the use of chemicals and pesticides which have harmful effects for human beings. There are several other demerits of the use of biocontrol methods too. The use of biocontrol agents causes a significant and noticeable deterioration in the quality of produce. The biocontrol agents do not eradicate all the pests and are a useful and economical tool for pest control only when used on a large scale.
List of Biological Control Agents
Insect-eating animals such as spiders, flies, ladybugs, wasps, beetles, and dragonflies.
Pathogenic microorganisms such as viruses, bacteria, fungi, etc. Coccobacillus bacteria are very dangerous to insects. They affect the digestive system and are used by insects and aphids. Entomophaga fungi are used against the green peach aphid.
Parasitoids lay eggs in the animal's body and kill it. It is later used as a food source for the young caterpillar. It is commonly used as a biocontrol agent.
Microbial Biocontrol Agents
Ladybird and dragonfly are two common insects that are used to eradicate aphids and mosquitoes in succession. Besides insects, microbes are also used as biocontrol agents. These viruses include viruses, fungi, viruses, and protozoans. Bacteria act as a biocontrol in three ways, causing pathogens or competing with or killing themselves.
Biotechnology has greatly expanded and improved many biocontrols. For example, Bacillus thuringiensis commonly referred to as Bt is a biological control agent. Spraying Bt solution made from seeds on plants will kill butterfly caterpillars. The dried seeds expel toxins from the intestines of worms and kill them.
Biotechnology has developed disease-resistant and insect-resistant plants by injecting B toxic B genes. thuringiensis in plants. For example, cotton. Trichoderma-like fungus and baculoviruses of the genus Nucleopolyhedrovirus are other microbial biocontrol agents. These agents are naturally straightforward; this and costs reduce their use.
What is ‘biological control’ and why do we need it?
Many farmers use chemical methods to control their pest problems, there are a few disadvantages to this method:
Chemicals may not clear and kill beneficial insects.
Insects may be resistant to pesticides.
Pesticides can enter food chains, accumulate and harm other organisms.
Chemical residues may harm people, especially farmers.
This has led to the development of Biological control methods. This is an insect control method that uses other predators or insect pests to reduce the number of pests to lower levels where there is minimal economic damage.
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Solved Examples
Why is A Fungus Used As A Biocontrol Agent?
Ans: Fungal biocontrol agents do not harm the environment and have proven themselves to be a cheap alternative to harmful chemical pesticides, and they also do not need to be ingested by the host but can invade them directly. They are an effective biological method of pest control.
Did You Know?
Aphiline refers to a braconid wasp that is used in controlling the aphid species from damaging crops. Aphiline works with the use of stinging and parasitizing the comparatively small aphid species such as the peach aphid and the cotton aphid. The female wasp also lays eggs within the aphid, and the larvae that come out from the hatched eggs feed on the female wasp's body causing the aphid to be nothing more than a mummy on the crop.
FAQs on Biocontrol Agents in Sustainable Pest Management
1. What are biocontrol agents?
Biocontrol agents are living organisms used to control agricultural pests, pathogens, or weeds in an eco-friendly way. They reduce pest populations naturally without relying on chemical pesticides. Common biological control agents include:
- Predators (e.g., ladybugs eating aphids)
- Parasitoids (e.g., Trichogramma wasps laying eggs in insect pests)
- Pathogens (e.g., Bacillus thuringiensis infecting insect larvae)
2. How do biocontrol agents work?
Biocontrol agents work by naturally suppressing pest populations through predation, parasitism, or infection. The main mechanisms include:
- Predation: One organism consumes the pest (e.g., spiders feeding on insects).
- Parasitism or parasitoidism: The agent lives in or on the pest and eventually kills it.
- Pathogenic action: Microorganisms like bacteria, fungi, or viruses infect and kill pests.
3. What are the main types of biocontrol agents?
The main types of biocontrol agents are predators, parasitoids, and pathogens. They are classified as:
- Predators – Free-living organisms that consume multiple pests (e.g., ladybird beetles).
- Parasitoids – Insects whose larvae develop inside a host and kill it (e.g., ichneumon wasps).
- Microbial agents – Microorganisms like Bacillus thuringiensis (Bt), fungi, and viruses that infect pests.
4. What is an example of a microbial biocontrol agent?
A common example of a microbial biocontrol agent is Bacillus thuringiensis (Bt), a soil bacterium that produces toxins lethal to insect larvae. Bt works by:
- Producing crystal (Cry) proteins that damage the insect gut.
- Specifically targeting caterpillars, mosquitoes, and beetle larvae.
- Being safe for humans and most non-target organisms.
5. What is the difference between biocontrol and chemical control?
The main difference between biocontrol and chemical control is that biocontrol uses living organisms, while chemical control uses synthetic pesticides. Key differences include:
- Biocontrol: Eco-friendly, target-specific, sustainable.
- Chemical control: Fast-acting but may cause resistance and environmental pollution.
- Biocontrol maintains ecological balance, whereas chemicals may harm beneficial organisms.
6. Why are biocontrol agents important in agriculture?
Biocontrol agents are important in agriculture because they reduce crop losses while minimizing environmental damage. Their benefits include:
- Lower dependence on chemical pesticides.
- Reduced risk of pesticide resistance.
- Protection of beneficial insects like pollinators.
- Support for sustainable farming practices.
7. What is classical biological control?
Classical biological control is the introduction of a natural enemy from a pest’s native region to control it in a new area. This method involves:
- Identifying the pest’s original habitat.
- Importing its natural predator or parasitoid.
- Establishing the agent in the new environment.
8. What is the role of fungi as biocontrol agents?
Fungi act as biocontrol agents by infecting and killing insect pests or plant pathogens. Important fungal agents include:
- Trichoderma – Controls soil-borne plant pathogens.
- Beauveria bassiana – Infects and kills insect pests.
9. Are biocontrol agents safe for humans and the environment?
Biocontrol agents are generally safe for humans and the environment because they are target-specific and naturally occurring organisms. Their safety features include:
- Minimal toxicity to humans and animals.
- Limited impact on non-target species.
- Biodegradability without harmful residues.
10. What is integrated pest management (IPM) and how do biocontrol agents fit into it?
Integrated pest management (IPM) is a sustainable approach that combines biological, cultural, physical, and chemical methods to control pests, with biocontrol agents as a key component. In IPM:
- Biological control is prioritized to reduce pest populations naturally.
- Chemical pesticides are used only when necessary.
- Monitoring and prevention strategies are applied regularly.
