Use of chemical pesticides is famous among farmers and gardeners to control pests in fields and gardens, but if you are into organic farming, biological controlling techniques are a must. Let’s know some of these techniques here.
To start with let’s first know about biological method of controlling the pests
Biological control is the control of harmful pests by using parasitoids, predators and by pathogens. In other words, biological control is an method by which natural enemies of an pest are encouraged, which are also multiplied artificially and are released by humans in order to control the pest population.
Controlling pests dates back to 400 BC when some of the Chinese farmers were using predaceous red ant (oecophylla) to control feeding of the pest on foliage of orange tress.
Various techniques of controlling the pests by biological control
1. Introduction method/ Classical biological control method
It is a method in which exotic natural enemies are deliberately introduced to a new location where they didn’t occur naturally. Once the natural enemies are established they continue to control the target pests efficiently.
2. Augmentation method
In this method, naturally occurring enemies are supported by releasing the reared natural enemies.
This involves 2 methods of introduction:
3. Inoculative method of releasing
In this method we release natural enemies only once in a season which increase its number in that season only. In this method the natural enemies controls the target pest from it’s progeny it self and also it’s subsequent generations too.
Like Acrophagus papayae when released @250/ha it controls papaya mealy bugs.
4. Inundative method of releasing
Here the natural enemies are multiplied and released periodically when the target pests reaches the damaging levels. The released natural enemies are not expected to increase its population when they are released. Additional releases are only made when the pests reaches the economic damage levels.
For example periodic release of egg parasitoid trichogramma chilonis @50, 000/ha at 4-6 releases of 10 day intervals.
5. By conservation method
In this method, naturally occurring natural enemies are preserved by environmental manipulation or by changing the production practices and also by protecting them from the predators of naturally occurring enemies.
Some of the important conservation measures include using selective insecticides which does not harm the natural enemies.
Another way is to avoid cultural practices which are harmful to the natural enemies and also by practicing favorable cultural practices like crop residue management and intercropping.
Advantages of biological control
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Biological control methods are safer to humans, and animals, and environment.
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These methods are host specific and don’t cause any side effects to non-target pests.
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These are economical, cost effective, and reduce need of chemical insecticides.
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Biological control is an effective method for long period of time as biological agents will survive as long as the pests are present.
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Even though biological control method is a slow process to control pest, it is effective and eliminates or reduces the need to apply chemical pesticides.
Author Details
Abhishek M, College of Agriculture, Vijayapura karnataka.
Contact no: 6362494151
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