An indoor farm grows basil plants on four racks. All four racks contain 40 plants and receive the same mineral solution.
Some plants develop malformed leaves and areas of decay on their stems. The grower records the following information.
| Rack | Plants showing signs on day 1 | Plants showing signs on day 8 | Aphids present |
|---|---|---|---|
| A | 3 | 15 | Yes |
| B | 0 | 7 | Yes |
| C | 0 | 0 | No |
| D | 0 | 0 | No |
Describe how the grower could use the evidence and further investigation to identify the cause of the damage. Explain why a conclusion should be reached quickly.
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.