Contents

Introduction to Biopesticides

Biopesticides, in a broader sense, refer to any substances whether living (e.g. microbes) or chemical compounds derived from natural sources (e.g. plant/microbial extracts, nanoparticles of biological origin) that are environment-friendly and significantly less toxic when compared against synthetic chemical pesticides¹. The input-intensive nature of food production, further aggravated by exponential growth in demand driven by population upsurge, the green revolution in agriculture resulted in huge usage of chemical pesticides and fertilizers. This, although, led to increased productivity and crop yield, has also resulted in heavy negative consequences for the entire ecosystem including both the environment as well as the being living in it ².

Biopesticides, owing to their sustainable and eco-friendly approach, are one of the best alternatives for pest management as well as for overcoming the harmful effects of chemical pesticides. Hence, this blog post will provide general information on biopesticides, their applications, advantages, and limitations. Although briefly dealt with, the harmful effects of chemical pesticides on the environment and the health of living beings will not be the major focus of this blog post series. This post will be the first of a series exploring the concept of biopesticides followed by a focus on individual/ specific components that have been classified as biopesticides.

Understanding Biopesticides

Biopesticide is an umbrella term designated to describe those components of natural origin for pest management which includes microbes and their extracts either as a whole or a specific chemical compound or their derivatives, plant extracts in their entirety or purified chemical compound or their derivatives, plant-incorporated protectants and nanoparticles produced using biological resources^1,3. These agents may be applied either individually or in combination for pest management to have a positive synergistic effect. Owing to their specific action on target species only, natural origin, and low cost of production, with no risk of residual effects unlike chemical pesticides, etc., they could be one of the key drivers for sustainable agriculture.

US Environment Protection Agency has classified biopesticides into three major classes (Fig. 1):

Biochemical Pesticides
Microbial Pesticides
Plant-Incorporated Protectants

Biochemical Pesticides

These are naturally occurring substances that control pests through non-toxic indirect mechanisms. For example, some of the secondary plant metabolites disrupt the sexual function of their targets. ⁴

Microbial Pesticides

Microorganisms such as protozoa, bacteria, fungi, nematodes, viruses, and oomycetes that are pathogenic to specific pests are used to control weeds, insect pests and plant pathogens.⁵

Plant-Incorporated Protectants

Pest-control substances directly expressed in genetically modified plants’ cells. Examples include cry proteins and double-stranded RNA that interfere with the native RNA of the pests.⁴

Figure 1: Classes of Biopesticides ⁶

Applications of Biopesticides

Agriculture

Biopesticides can be effectively applied in agriculture, especially for promoting organic farming and also as a component of the Integrated Pest Management (IPM) practices. Example: Trichoderma is a well-known biocontrol agent that works against both plant fungal pathogens as well as insect pests.⁷

Forestry

Traditional use of chemical pesticides can result in severe loss of soil microbial diversity, reduction in pollinator population, and harm to non-target species. The use of biopesticides can facilitate overcoming these problems during forest management.⁸

Public Health

Biopesticides can also be used to control known vectors of disease-causing pathogens. Example: Bacillus thuringiensis israelensis can be effectively used to control mosquito population.⁹

Advantages of Biopesticides

Environmental Safety

Synthetic chemical pesticidal have high negative impact on the environment resulting in ecosystem imbalance. In contrast, biopesticides are biodegradable, hence reducing chemical pollution in the environment and protecting ecosystems. Chemical pesticides have variable persistence in the environment depending on their type and application frequency, which could contribute to soil and water contamination. The use of biopesticides can reduce such contamination, and protect environmental health as well as that of its inhabitants.

Non-Toxic to Non-Target Organisms

Unlike chemical pesticides that have a broad host range which can affect both target and non-target species, biopesticides have a narrow host range. Hence, the use of biopesticides helps in reducing the toxic effects of chemical pesticides on non-target species with minimal harm to beneficial insects and bystanders. Incorporated into Integrated Pest Management (IPM), biopesticides can effectively reduce the use of chemical pesticides while maintaining crop yield.

Reduced Chemical Residues

Reduced use of chemical pesticides subsequently promotes safer food products as they have fewer chemical residues. This will also provide health benefits to farmers, consumers, and workers.

Sustainability

Long-term pest control can be achieved through the effective and efficient use of biopesticides. Owing to their multi-prong approach during pest control, the chances for resistance development in pests are reduced.¹⁰

Table: Conventional Chemical Pesticides vs Biopesticides¹¹

Challenges and Limitations

Short Residual Activity

Due to their short persistence in the environment, timing and frequency need to be aligned perfectly to achieve the highest levels of efficacy.

Efficacy Variability

The efficacy of the biopesticides can vary significantly based on their type as well as environmental and application conditions.

Regulatory Hurdles

Although significant flexibility has been gained to produce biopesticides as a sustainable alternative to chemical pesticides, strong cooperation between government agencies and commercial entities needs to be built for the successful and viable integration of biopesticides into routine farming. Technological and policy gaps need to be filled to fast-track the production of biopesticides while maintaining transparency in their safety and efficacy.¹²

Using Biopesticides at Home

With the rise in subsistence farming, biopesticides could be one of the best alternatives for use in home gardens and roof-top gardens.

Future Outlook

Increased awareness among consumer for safe food, active petitioning by the environmentalists for nature conservation, and technological advances in sustainable production and increased efficiency of biopesticides have brought on positive growth for the commercial potential of biopesticides. Market trends show an increasing market share for biopesticides.

Conclusion

The benefits of biopesticides not only outweigh the benefits of chemical pesticides but their effective application can help mitigate the chemical pollution in the environment and the subsequent associated risks, leading to healthy and sustainable growth. Government policies and awareness education play vital role towards quicker adoption of biopesticides for better farming and a sustainable future.

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References

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