大象传媒

Crop protectionBiological control

Farmers need to protect their crops against damage caused by weeds, pests and disease. To do this, they use cultural and chemical control methods. However, there are disadvantages to consider for each of these methods.

Part of BiologySustainability and interdependence

Biological control

Biological control reduces the pest population by using a natural parasite, predator or pathogen of the pest. This natural enemy is the control agent.

Timing of the introduction of the biological control is really important. Using biological control avoids resistance, persistence and introduction of harmful chemicals.

A circle of card that has wasps hatched on it
Figure caption,
Wasps hatched on circle of card

A heated glasshouse is an ideal location for biological control as it is enclosed and the temperature can be altered to suit the specific control agent.

Examples of biological control include:

  • control of glasshouse whitefly with the parasite wasp Encarsia
  • control of glasshouse red spider mite with Phytoseiulus
  • control of butterfly caterpillars with the bacterium Bacillus thuringiensis

Risks with using biological control include the control organism becoming an invasive species, or it becoming a parasite, predator or pathogen of another species.

Successful pest management includes a combination of cultural, chemical and biological control. This is known as Integrated Pest Management.

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