# Describe how biological control can be used to reduce pest numbers on a crop, and explain one advantage and one disadvantage of using biological control instead of pesticides.

> Pearson Edexcel International GCSE Biology (4BI1) — 5.1 Food production · Describe · 4 marks

> Farmers can reduce pest damage to crops either by applying pesticides or by using biological control methods that introduce another species to kill the pest.

## Mark scheme (4 marks)

1. Biological control involves introducing/using another species (natural predator/parasite) to kill or reduce the numbers of the pest
2. The introduced species feeds on / kills / reduces the population of the pest
3. One advantage: biological control does not involve chemicals / pesticides, so there is no chemical pollution of the environment / soil / water / does not harm non-target organisms / is more sustainable
4. One disadvantage: the introduced species may become a pest itself / may affect other species in the ecosystem / may be difficult to control once released / biological control acts more slowly than pesticides

## Key terms

- [biological control](https://www.gradenine.co.uk/glossary/biological-control)
- [pesticides](https://www.gradenine.co.uk/glossary/pesticides)

## Related

- [Revision notes for Pearson Edexcel International GCSE Biology (4BI1)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/describe-how-biological-control-can-be-58f78b87) · Published by Druglandscape Ltd.