Whitefly are insect pests of tomato plants grown in glasshouses.
Encarsia is a small wasp. It lays its eggs inside young whitefly. The young wasps kill the whitefly.
A grower compared two methods of controlling whitefly over one year.
The Table shows the results.
Table
| Pesticide | Encarsia wasps | |
|---|---|---|
| Cost per year in £ | 1200 | 1800 |
| Percentage of tomato crop lost to whitefly | 6 | 4 |
| Number of times the treatment was applied | 12 | 2 |
| Pesticide found on the tomatoes | yes | no |
When no crop is lost, the grower harvests 50 000 kg50\,000\ \text{kg}50000 kg of tomatoes.
Calculate the extra mass of tomatoes the grower would harvest by using Encarsia wasps instead of pesticide.
Evaluate which method the grower should use.
Use data from the Table in your answer.
Explain why using Encarsia wasps inside a glasshouse is less risky than releasing them into the wild.
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.