A fungal pathogen infects the leaves of a shrub. Workers divide infected shrubs into two groups and treat them differently for three weeks.
| Group | Treatment | Mean number of newly infected leaves per shrub after three weeks |
|---|---|---|
| A | Leaves showing signs of infection were removed each day | 3 |
| B | Leaves showing signs of infection were not removed | 11 |
Explain why fewer newly infected leaves developed in group A than in group B.
133 exam-style questions on AQA GCSE Biology 3.3 Plant disease, covering 3.3.1 Detection and identification of plant diseases and 3.3.2 Plant defence responses. Each one has a worked solution and a mark scheme showing where the marks go.