The word 'pollution' over a background of a smoking chimney.
University of Bristol
Wellcome Trust
Recommended by:
Society of Biology
PEEP for Physics & Ethics at GCSE
 

Pollution

Biological Pest Control – a better way to reduce pests.


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.

 

Next: Pollution from fossil fuels





Adult
Emerging female
Parasitized whitefly
Emergence hole

Click to enlarge photos
 
Photos copyright © 2003
The Regents of the
University of California.
All rights reserved.


What's your opinion?

Average rating

Not yet rated

Read comments

speech bubble  No comments yet. Why not be the first person to add one?