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

Large amounts of crops of the same type tend to be susceptible to pests, which use the crops for food. this reduces the amount of crop yielded and therefore the farmers profit is reduced.

To overcome this farmers use two solutions:

1. Pesticides 

Advantages

.Pesticides are chemicals so they are easy to obtain

.Easy to apply 

.Very effective

Disadvantages 

. Pesticides can be toxic, they could kill other animals and plants, then the pests they are aimed to kill.

   -pesticides can also be harmful to humans

.Bio accumulation  is when pesticides build up through the food chain causing problems for animals higher in the food chain.

.Mutation in the pests often leads to resistance which means pesticides have to be applied in higher concentration therefore the pesticide is more toxic or the pesticide no longer works and then the farmers have to find alternative pesticides 

2. Biological Control 

Advantages

. No toxic chemicals  

. less  impact on the wildlife, or humans

Disadvantages 

. Not 100% effective
. Can be difficult to control, there is a danger that the introduced species would start preying on a    alternative prey so it will not die out
. It is difficult to match a predator to prey
. It can take a long time