5.4 Pest control

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

A large field of crops of the same type is called a monoculture. These are very susceptible to pests which use the crop as their food source which reduces crop yield for the farmers.

Pesticides
To overcome this pesticides are used – Chemicals designed to kill the pests

Advantages

• Chemicals – easy to obtain
• Easy to apply – spray
• Very effective

Disadvantages

• Toxic – harmful to other species other than the pests (inc. humans)
• Bioaccumulation – the pesticide causes problems in the higher levels of the food chain
• Mutation in the pests leads to resistance.

Biological Control
Biological control is reducing the population of a pest without using pesticides.

For example if pest enters a country and flourishes it is often important to attempt to remove this species so that the native species can flourish again. In order to do this another alien species must be brought in that is higher in the food chain to reduce the numbers of the problematic plant/animal

Advantages

• No toxic chemicals
• Less impact on man/wildlife

Disadvantages

• Not 100% effective
• Difficult to control
• The alien species may not die out once the pest has been removed and could become another problem