Overview
- What is biological control?
- Biological pest control as a natural alternative to pesticides
- What’s the goal of biological pest control and who should use it?
- Why is biological pest control needed?
- What are the different types of biological pest control?
- What are the different biological control agents?
- The advantages of biological control
- The challenges of biological pest control
What is biological control?
Biological control, shortened to biocontrol (or ‘bioprotection’), is an approach using living organisms and naturally-sourced (or nature-identical) compounds to control pest populations in agriculture production.
Biological control involves the use of biological products on crops by farmers and can involve the introduction of natural enemies to manage invasive species that harm agriculture.
The IBMA (International Biocontrol Manufacturers Association) defines biocontrol products as:
Tools originating from nature, with low impact on human health and the environment, manage pests, weeds, and diseases.
People have successfully used this approach for over 100 years to manage the spread of pests, protect crops, and restore balance to ecosystems and habitats.
Biological pest control as a natural alternative to pesticides
Biological control takes natural technologies and uses them to control agricultural pests in an environmentally safe way. Biocontrol products can easily be incorporated into an Integrated Pest Management (IPM) programme, a sustainable approach to manage pests. When used correctly, it can enable growers to reduce the use of synthetic chemicals, which can have a devastatingly negative impact on humans, wildlife and soil health.
At CABI, classical biological control has been proven as an effective way to control invasive or non-native species through the release of biological control agents. Invasive species or non-native pests are often organisms that moved to new environments without, or with few, natural enemies, enabling unchecked spread.
What’s the goal of biological pest control and who should use it?
The goal of biocontrol is to protect growers from unwanted agricultural pests, plant pathogens and weeds whilst not endangering humans, harming wildlife or enabling pesticide resistance. It might be used as a quick attack method or as a prolonged build-up of immunity in the growing system. It also suits people interested in organic and sustainable farming.
Why is biological pest control needed?
Biological control methods are rising in popularity due to the safety and pesticide resistance concerns surrounding traditional chemical pesticides. Biological control can help reduce the reliance on these chemical pesticides, which are harmful to the environment, wildlife, and human health. In addition, the growing demand of low residue and/or organic foods from consumers has resulted in increase interest in more natural, sustainable methods of pest control.
Invasive pests are also of great concern as they can lead to significant crop losses and reduced food security. Controlling these invaders requires coordinated efforts, such as sustainable management practices like biological control.
Reduce synthetic chemical inputs
Synthetic chemical pesticides can have detrimental effects on a variety of factors in agriculture. They can disrupt soil life which then limits basic processes of plant growth and vigour. They can harm wildlife in and around the farm, for example, beneficial insects like pollinators, predators and parasitoid wasps. Chemical pesticides also pollute water bodies through runoff or drift.
Toxic synthetic pesticides can directly impact human health, due to direct exposure, food and water contamination.
These chemicals can also induce pesticide resistance in the target host, making them less, or no longer effective. Coupled with disruption to soil health and beneficial organisms, synthetic pesticides can negatively impact crop production, consequently affecting livelihoods.
New pests and diseases
Increasing trade and travel between countries has resulted in non-native species landing in foreign locations, wreaking havoc on delicately balanced native ecosystems. These species, often introduced unintentionally, can rapidly spread due to the absence of natural predators, pathogens, and competitors that normally control them. This gives the invading pest a huge unfair advantage over its native neighbors.
What are the different types of biological pest control?
There are several different strategies or types of biological control: augmentative, classical (importation), and conservation.
Augmentative biological control
Augmentative biological control involves increasing the number of natural enemies or pathogens of the pest. A natural enemy or pathogen can be, for example, a microorganism or a predatory insect or mite capable of controlling a pest population. Biopesticides can be used in this strategy.
The release can be small but consistent over or across seasons (inoculative). This is more of a prevention method. It can also be a larger release looking for more of an immediate impact (inundative).
Augmentative biological control usually has an immediate effect but might not last long. This is why it can need repeated releases of a control agent.
Classical biological control
Classical biological control, also known as importation biological control, introduces an exotic organism to control an invasive pest.
The aim is not to eradicate the invasive organism, but to bring its density below a suitable ecological or economic threshold. The released natural enemy usually establishes in the environment and can sustain a population to manage the pest for many years.
CABI – the organization that manages the CABI BioProtection Portal – has a rich history of classical biological control. It investigates potential biological control agents that can be introduced to control various invasive species globally. Its work has included releases of the biological control agent Diadromus pulchellus, a wasp species used to control the invasive leek moth, Acrolepiopsis assectella, in Canada
Conservation biological control
Conservation biological control is the preservation – or conservation – of natural enemies that already exist in the environment and control a pest population. This is one of the most straightforward strategies or types of biological control as the natural enemies are already present in the environment and doing their job. The aim of conservation biological control is to maintain and enhance the biological control agent.
- For an example of conservation biocontrol, you can read SAN’s resource on Native Plant Resources for Natural Enemies of Oil Palm Herbivores in Malaysia. This document describes insect networks that can be added in oil palm plantations to attract beneficial insects, which help control oil palm pests.
What are the different biological control agents?
There are various types of biological control agents, or biopesticide and biocontrol products. These include microbials, natural substances, semiochemicals and macrobials (invertebrates such as insects, mites, nematodes). These biological control agents can disrupt, deter, or kill pests and diseases attacking plants
Microbials
This group contains bacteria, fungi, viruses and other microorganisms that have the capacity to kill pests or outcompete and prevent diseases. Trichoderma is well known example of a microbial biopesticide.
Global registration and mass production make microbials widely available for protecting plants against various pests and diseases.
They relate to a pest or disease control method that contains microbes or microorganisms – very small living things
Natural substances
Natural substances are made of components, including natural chemicals, that originate from nature and have antimicrobial, insecticidal or pest repellent activity. They might be obtained from plants, animals, and microorganisms, though not exclusively. They can also be synthetic copies of their original form. This is, for example, thyme oil or azadirachtin.
Semiochemicals
Animals or plants produce semiochemicals, which are message-bearing compounds used to change and disrupt a pest’s normal behaviour.
A semiochemical biopesticide can contain one or more pheromones or chemical compounds which modify the pest’s behaviour, ultimately leading to the population decreasing.
Macrobials
Macrobials, or sometimes called invertebrate biocontrol agents, include insects, nematodes and mites that when released will parasitize and/or feed on pests.
Beneficial parasitoids, also called parasitic wasps, can help control populations of Lepidopteran butterflies and moths. Parasitoids can lay their eggs inside or outside the host, the pest, which will prevent its growth and eventually cause its death.
A well-known macrobial agent is predatory mites, such as Amblyseius swirskii, or the rove beetle Atheta coriara.
The advantages of biological control
Targeted
Biological plant protection products are selected for their specific ability to combat a particular plant pest or disease, ensuring a high success rate. Their targeted action also means that it minimizes the risk of harming non-target species.
Learn more about how bioprotection methods can seek out pests.
Sustainable
The use of natural control methods means it is highly unlikely there will be adverse effects to people, wildlife or the environment. It is a viable long-term solution applicable to all types of growing, including farms, private gardens, and greenhouses.
Learn more about how bioprotection is environmentally friendly.
Cost
Growers can sometimes source natural products at a lower price than synthetic chemical pesticides. But also, over the longer-term, by promoting better soil health and avoiding repeated applications of failing/resistant chemical pesticides, biologicals can become very cost effective.
With classical biological control this can be a permanent, self-sustaining solution. Once implemented there is no need to re-apply.
Little to no residues
Bioprotection products leave little to no residues on crops, making them an attractive option for growers aiming to produce clean, safe food. Unlike chemical pesticides, biological products break down quickly and are less likely to accumulate on harvested produce. This low-residue profile not only supports consumer health and safety but also aligns with organic farming standards and meets food safety regulations.
Read more about how biocontrol can help farmer to access more markets.
Safety
Bioprotection products sourced from nature are unlikely to have any dangerous side effects. On the other hand, side effects from some of the more toxic chemical pesticides are common. This includes acute (short-term) and chronical (long-term) effects on affects people, plants and ecosystems.
Learn more about how biocontrol can be a safer alternative to chemical pesticides.
Resistance
Biological controls bring new modes of action compared to their chemical counterparts, which slows down the rate of pesticide resistance, bringing it to manageable levels. Scientists are continuously looking for new biological organisms and modes of action to be ahead of the game.
Learn more about how bioprotection can slow pest resistance.
Compatibility with Integrated Pest Management (IPM) approaches
Biological products can easily be incorporated into an IPM programme, as they are often compatible with other pest control methods, such as cultural, mechanical, and chemical strategies.
This integration supports long-term pest control while minimizing environmental impact and preserving beneficial organisms.
The challenges of biological pest control
Storage
Due to the ‘live’ nature of biocontrol methods, they often need appropriate storage facilities, such as refrigeration to keep the components usable, which some growers may not have access to. However, in these cases, one could source an alternative biocontrol method that does not require specific storage means.
Education
As a relatively new method of pest control, some growers may not have the knowledge they need to properly implement biological control. Or they may prefer to stay with methods they have previously tried.
Saying this, biocontrol products will always come with labels and detailed instructions for how to use them. Plus, advisors (where available) will be able to give good tips on how to use the products to ensure efficacy.
User education is an issue that CABI actively work to improve, including on projects such as the CABI BioProtection Portal and the Plantwise Plus programme.
Useful links
The Introduction to Bioprotection Products online course explains what bioprotection products are and how they work in the field. It draws on CABI’s extensive experience in developing scientifically sound biological control solutions to control crop pests and diseases.
