Aphids are insects that feed on plants. Aphids are pests of bean plants.
A farmer grows bean plants in two greenhouses.
The Table shows the mean number of aphids on each plant in the two greenhouses.
Table
| Week | Mean number of aphids per plant in greenhouse 1 (pesticide) | Mean number of aphids per plant in greenhouse 2 (ladybirds) |
|---|---|---|
| 0 | 120 | 120 |
| 1 | 15 | 92 |
| 2 | 38 | 55 |
| 3 | 84 | 26 |
| 4 | 131 | 12 |
Name the method of controlling pests used in greenhouse 2.
Use the Table to compare the effect of the pesticide and the ladybirds on the number of aphids.
Suggest why the number of aphids in greenhouse 1 increases after week 1.
Suggest one disadvantage of using ladybirds to control aphids.
127 exam-style questions on OCR GCSE Biology 6.2 Feeding the human race, covering 6.2.1 Biological factors affecting food security, 6.2.2 Agricultural solutions to growing demand, 6.2.3 Selective breeding, 6.2.4 Genetic engineering, 6.2.5 Steps in genetic engineering, 6.2.6 Benefits and risks of gene technology in agriculture, and 6.2.7 Biotechnological solutions to growing demand. Each one has a worked solution and a mark scheme showing where the marks go.