5.4b Biological control

understand the reasons for pest control and the advantages and disadvantages of using biological control with crop plants.


an example of controlling a pest (plant) by a herbivore (moth) called biological control - not using pesticides.

-in australia the prickly pair cactus of north america was introduced into gardens. the cactus started to cover agricultural land so it was necessary to get rid of it. there was no natural predator of the cactus so an alien species of another country had to be introduced. moth -> feeds on the cactus. (cactoblastis) =
-moth was introduced and there was no competitors so it was able to eat away the cactus and remove it away from agricultural land.

PROS-
-no toxic chemicals involved
-less impact on humans and wildlife.

CONS-
-not 100 percent effective.
-difficult to control. -always a danger. the species might find alternative prey to feed and will not die out. (eg. famous- cane toad in australia)
-difficult to match a predator to the prey. (cannot find suitable predator to remove pest)