An example in more detail:
The parasitic wasp (Ecasaria Formosa) and the control of whitefly (Trialeurodes vaporarium
- A glasshouse is an ideal place for growing plants but also an ideal habitat for a pest.
- Tomatoes and cucumbers can have a serious pest called a white fly.
- This small moth-like insect lives for 35 days and each female can produce up to 500 eggs.
- The adult and larva feed by sucking sap. They produce a sticky sugary secretion which encourages fungal growth on the leaves and fruits. This seriously disrupts photosynthesis and therefore crop yields.
- The whitefly can be controlled by insecticides although the pest is now showing resistance.
- Biological control involves introducing a parasitic wasp (Encarsia formosa) into the glasshouse. The female wasps lay eggs on the whitefly. These hatch into minute larvae which pupate and kill the host whitefly.
- These emergent adults then continue the cycle, females laying 60-100 eggs.
- The method is cheap and highly effective in controlling the pest.
What happens when biological control does not work effectively? Is integrated control the future?
- Often biological control cannot work entirely on its own as pest numbers are difficult to control, especially at the beginning of an infestation.
- New methods now use biological control in conjunction with other control methods – this is known as integrated control.
- Additional methods could include:
- Producing pest-resistant crops.
- Cultivation techniques to reduce pest numbers.
- Targeted application of highly-specific pesticides.
Pollution from fossil fuels