This subtopic explores how agroecology principles—such as enhancing biodiversity, recycling nutrients, and minimising disturbance—are applied to manage pes
Topic Synopsis
This subtopic explores how agroecology principles—such as enhancing biodiversity, recycling nutrients, and minimising disturbance—are applied to manage pests, weeds, and diseases in regenerative land-based systems. It emphasises ecological processes over synthetic inputs, promoting practices like crop diversification, habitat creation for natural enemies, and soil health improvement to reduce vulnerability. Learners will examine the practical integration of these principles into farm design and day-to-day operations for resilient and productive systems.
Key Concepts & Core Principles
- Soil health: Understanding soil as a living ecosystem, including the role of organic matter, soil organisms, and mycorrhizal fungi in nutrient cycling and water retention.
- Holistic management: Applying principles of planned grazing, cover cropping, and minimal tillage to mimic natural ecosystems and build soil structure.
- Biodiversity enhancement: Using polycultures, hedgerows, and buffer strips to support beneficial insects, pollinators, and wildlife, reducing pest pressure naturally.
- Water cycle management: Techniques such as keyline design, swales, and mulching to improve infiltration, reduce runoff, and increase drought resilience.
- Carbon sequestration: Practices that capture atmospheric carbon in soil organic matter, mitigating climate change while improving soil fertility.
Exam Tips & Revision Strategies
- When tackling written assignments, always link each practice back to the underlying agroecological principle (e.g., increasing functional biodiversity) rather than just listing techniques.
- Use case studies or examples from real farms to illustrate how agroecological practices are combined for effective pest, weed, and disease control—this demonstrates applied understanding.
- Be specific about the mechanisms: explain how a polyculture reduces pest load (e.g., by disrupting host-finding ability) rather than stating it works without explanation.
- For assessment tasks requiring evaluation, weigh both benefits and limitations of practices, such as the time lag before natural enemy populations establish or the additional labour needed for mechanical weeding.
- Reference key ecological concepts (e.g., trophic cascades, competition, allelopathy) where relevant to show depth of knowledge and meet higher-level marking criteria.
Common Misconceptions & Mistakes to Avoid
- Confusing agroecological pest control with simple organic substitution—failing to recognise that agroecology relies on system redesign rather than just replacing synthetic pesticides with natural ones.
- Overlooking the importance of monitoring and economic thresholds, leading to the assumption that no action is needed once natural enemies are present.
- Assuming that all companion plants are universally beneficial without considering specific pest-host interactions or local ecological relationships.
- Neglecting the role of crop rotation and crop diversity in disease prevention, instead focusing solely on reactive controls.
- Misunderstanding the difference between suppression and eradication; expecting agroecological methods to eliminate all pests or weeds rather than maintaining them at manageable levels.
Examiner Marking Points
- Award credit for clearly explaining how enhancing on-farm biodiversity (e.g., insectary strips, companion planting) disrupts pest and disease cycles.
- Award credit for describing specific agroecological practices (e.g., use of predator habitats, mulching, allelopathic crops) and linking them to weed, pest, or disease suppression.
- Award credit for demonstrating an understanding of the role of soil health in plant immunity and how practices like cover cropping and reduced tillage contribute to disease and pest resilience.
- Award credit for evaluating the trade-offs and synergies between different agroecological practices for integrated pest, weed, and disease management.
- Award credit for providing practical, site-specific examples of how principles are adapted to control a particular pest, weed, or disease in a given context.