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examBoard: Pearson Edexcel
examType: IGCSE
lessonTitle: Predation Control
In food production systems, predators and pests can significantly reduce crop yields and livestock productivity. Effective predation control is essential for maintaining food security and agricultural efficiency. This section explores how farmers and food producers manage predators to protect their produce and livestock.
Key Definitions:
Without effective predation control, global food production would decrease by an estimated 30-40%. Pests and predators can destroy crops in fields, damage stored food and harm livestock. In developing countries, these losses can be even more severe, threatening food security for millions of people.
While controlling harmful predators is necessary, many predators also play beneficial roles in ecosystems. For example, birds of prey control rodent populations and many insects are important pollinators. The challenge is finding control methods that target harmful species while preserving beneficial ones.
Biological control methods use living organisms to manage pest populations. These approaches often work with natural ecological processes rather than against them.
Introducing or encouraging natural enemies of pests can effectively control their populations. This approach mimics natural ecosystem balances.
Ladybirds (ladybugs) are voracious predators of aphids. One ladybird can consume up to 5,000 aphids in its lifetime, making them excellent for controlling these crop pests.
These tiny wasps lay eggs inside pest insects. When the eggs hatch, the larvae consume the host from within. They're particularly effective against caterpillars and aphids.
Microscopic roundworms can be applied to soil to control pests like weevils and grubs. They enter the pest's body and release bacteria that kill the host.
Growing certain plants together can help deter pests or attract beneficial predators. This traditional method is gaining renewed interest in sustainable farming.
Plants like marigolds, garlic and basil produce compounds that repel certain pests. For example, marigolds release a substance that deters nematodes in the soil, protecting neighbouring plants.
Flowers like sunflowers and lavender attract beneficial insects such as hoverflies and parasitic wasps, which prey on crop pests. These "insectary plants" create a natural defence system.
Chemical controls remain widely used in modern agriculture, though their application is becoming more targeted and regulated due to environmental concerns.
Different chemical compounds target specific pests or have particular modes of action. Understanding these differences is crucial for effective and responsible use.
These target insect pests and come in various forms including contact, systemic and residual types. Modern insecticides are increasingly designed to target specific pest species.
Used to control rats, mice and other rodent pests that can damage crops and contaminate stored food. Most work by preventing blood clotting, causing internal bleeding.
These use synthetic versions of insect communication chemicals to disrupt mating or attract pests to traps. They're highly specific and have minimal environmental impact.
UK apple growers have dramatically reduced pesticide use through integrated pest management. By introducing predatory mites to control spider mites and using pheromone traps to disrupt codling moth mating, many orchards have cut chemical applications by over 60%. Growers also maintain hedgerows and flower strips to support natural predators like birds and beneficial insects. This approach has not only reduced environmental impact but also lowered production costs and improved fruit quality, as fewer chemical residues remain on the apples.
IPM combines multiple control strategies in a systematic approach that minimises environmental impact while effectively managing pests. It's considered the most sustainable approach to predation control in modern agriculture.
Effective IPM follows these key principles to create a comprehensive management strategy:
Regular crop inspection and early detection of pests before they reach damaging levels. This includes using traps, visual inspection and understanding pest life cycles to predict problems.
Taking action only when pest populations reach levels that would cause economic damage. This prevents unnecessary treatments when pest numbers are too low to impact yields significantly.
Using a combination of biological, cultural, physical and chemical controls rather than relying on a single method. This creates multiple barriers to pest success.
Selecting control methods that have the least impact on non-target organisms and the environment while still effectively managing the pest.
Maintaining detailed records of pest populations, treatments and results to improve future management decisions and track the effectiveness of different approaches.
Different control methods have varying impacts on the environment, non-target species and ecosystem health. Understanding these impacts is crucial for sustainable food production.
Chemical pesticides can have unintended consequences, including killing beneficial insects like bees and predatory beetles. Some pesticides persist in the environment, accumulating in soil or water. Bioaccumulation can occur when chemicals concentrate up the food chain, affecting birds of prey and other top predators. Additionally, pests can develop resistance to frequently used chemicals, requiring higher doses or new formulations.
Integrated approaches reduce chemical use, preserving biodiversity and ecosystem services like pollination and natural pest control. They're often more sustainable long-term as they don't lead to resistance issues as quickly. These methods typically have lower impacts on water quality and soil health. Many integrated techniques also help build resilience against climate change by promoting diverse, adaptable farming systems.
When the cassava mealybug threatened cassava crops across Africa in the 1980s, scientists introduced a parasitic wasp (Anagyrus lopezi) from South America that specifically targeted this pest. The wasp established itself across 30 countries, bringing the mealybug under control without chemicals. This biological control program saved an estimated $20 billion in crop losses and helped secure food supplies for millions of people. The program is considered one of the most successful examples of biological control in agricultural history.
As our understanding of ecology improves and technology advances, new approaches to predation control are emerging that promise greater effectiveness with reduced environmental impact.
Innovation is driving new solutions to predation control challenges:
Methods like RNA interference can target specific pest species by disrupting essential genes. Unlike traditional GMOs, these approaches don't permanently alter the organism's genome.
Smart traps with cameras and AI can identify and count specific pests, sending real-time alerts to farmers when intervention is needed, enabling precise timing of controls.
Drone and robot technology allows for targeted application of controls only where needed, reducing the amount used and minimising impact on beneficial organisms.
Effective predation control is essential for food security, but must be balanced with environmental protection. The most successful approaches integrate multiple methods, minimise chemical use and work with natural processes rather than against them. As our understanding of ecology deepens and technology advances, predation control is becoming more precise, effective and environmentally sustainable.
Predation control is vital for food production, but approaches that rely solely on chemicals can harm the environment and lead to resistance. Biological controls and integrated approaches offer sustainable alternatives that often provide better long-term results. The future of predation control lies in precision, targeting specific pests with minimal impact on beneficial organisms and ecosystems.
Be prepared to compare and contrast different predation control methods, explaining their advantages and disadvantages. Understand specific examples of biological control agents and how they work. Know the principles of Integrated Pest Management and be able to apply them to different scenarios. Remember case studies that demonstrate successful predation control approaches.
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