EM-Agriculture and the environment, Page no 70-74
Biological control is the use by humans of beneficial insects such as predators and parasitosis, or pathogens such as fungi and viruses, to control unwanted insects, weeds, or diseases. Biological control dates back to 324 BC, when Chinese growers were recorded using ants to feed on citrus pests. Ex: the destruction of the cartophiles mealybug in California by two parasitic species of chalcid wasps imported from Australia, Sarcophagus gurney and Terraneous pretiosus.
Advantages of biological control:
No chemical residues are left in the crop.
There is no impact of sprays on the surrounding ecosystem.
There is no need to wear protective clothing when applying the predator.
When the pest has been controlled, the lack of food will mean the predator will naturally reduce in numbers.
Disadvantages of biological control:
The control is not as instant as chemical control.
Climatic conditions might mean the pest breeds faster than the predator, so the problem is not controlled.
The predator might not stay on the crop and move elsewhere, instead of feeding on the intended pest.
The predator might escape into the local countryside and impact the natural ecosystem and food web
THE END