Ch 6: Biological Control Methods

Biological control is the process of pest management by the use of living organisms that prey on or attack pests. Three important steps are generally required to improve the biological control of pests:

• Find out which natural enemies are present.
  • Insect zoo 
    To find out who is eating who or what, an “insect zoo” can be set up. A small group of suspected pests and natural enemies are kept together in ventilated jars or other small containers with a small portion of the crop, for example kale leaves. Always make sure that the insects have fresh food. Keep the zoo in a shaded place to avoid high temperature. Take care that the environment inside the zoo does not get too dry or too humid. Maintain the insect zoo all of them have gone through their complete development, so that you can see who eats who or what. Insect zoos can be used to study the life cycle of insects and their behaviour. They are also very useful to study the effects of predators or Bt.
  • In most cropping systems natural enemies are already present or close by and do not need to be introduced. It is crucial that natural enemies can be recognised and distinguished from pests.
  • Select appropriate cultivars
  • It is important to choose crop cultivars that are not highly susceptible to pests and diseases. Information on the susceptibility of different cultivars can often be obtained by asking other farmers, extension staff or relevant research institutes. If the information is not available, it may even be useful to run on-farm trials of different cultivars
  • Conserve natural enemies by cultural means 
    There are many ways to encourage natural enemies on your farm:Providing food sources for adult stages of natural enemies such as flowering plants (fennel, thistles, coriander, Indian mustard and other flowering brassicas) close to the crop
    Mixed cropping systems provide food and shelter and attract a wider range of natural enemies. Green manure plant such as legumes and sun hemp grown in rotation with other vegetables also improve soil fertility.
    Live fences (trees, hedges) act as windbreaks and provide shelter for natural enemies.
    Mulches around plants provide attractive environments for ground-living predators such as beetles and spiders.