5.4b Biological control

1. In Australia the prickly pair cactus of north america was introduces to garden which escaped into the countryside and the prickly pair cactus flourished under the Australian climate. 
2. However, it started taking up a lot of the agricultural land therefore it was important to get rid of it. 
3. An alien species, a moth (cactoblastis), was introduced, which feeds on the cactus. This moth had no competitors and therefore it was able to eat away at the cactus and remove it from the land. 
4. This is an example of controlling the pest. In this case, the cactus is the pest, which is eaten away by the herbivore. This is called biological control. In this case, we're not using pesticides.
5. Advantages of biological controls: 
1. No toxic chemicals involved means it has less impact on man or on wildlife.
6. Disadvantages 
1. Not a 100 percent effective 
2. There is always a danger that the introduced species will find an alternative prey on which to feed and will not die out once the pest is removed therefore it is difficult to control.
3. It is difficult to match a predator to the prey. you can;t actually find a suitable predatory herbivorous animal to remove your pest.