Biological Pest Control
Biological control is a method of controlling pests using other living organisms (or their natural enemies). It relies on predation, parasitism, herbivory, or other natural mechanisms. Natural enemies of pests, also known as biological control agents, include predators, parasites and pathogens.
Predators
Predators are mainly free-living animals that directly feed on other animals or preys. Examples
o Ladybugs are voracious predators of aphids, scale insects and small caterpillars.
o Dragonflies are important predators of mosquitoes. In water, the dragonfly larvae eat mosquito larvae, and on land, adult dragonflies capture and eat adult mosquitoes.
o Tilapia can be used to control mosquito larvae and pupae in stagnant water.
Parasites/Parasitoids
Parasitoids are insects that lay their eggs on or inside the body of another animal or insect host. The hatched newborns feed off the body, eventually killing the host. Example
o Wasps attack caterpillars and a wide range of insects including greenfly, whitefly, cabbage caterpillars
Pathogens
o Bacillus thuringiensis is widely used to control moth, butterfly and beetle. The bacteria available in sachets of dried spores are mixed with water and sprayed onto vulnerable plants such as fruit trees.
o Trichoderma species are used to manage certain plant pathogens.
Advantages of Biological Control
o It is cheaper than chemical pest control
o Environmental pollution is reduced
Disadvantages of Biological Control
o Control agents that are not restricted to a single species can cause changes in ecological niche which may directly affect the ecosystem
