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

 Pesticides are substances that are used to prevent, destroy or repel pests.

There are 3 different types of pesticides, which all target different types of organisms:

-        Herbicides – kills unwanted plants (weeds etc.)

-        Fungicides – kills fungi (e.g mold)

-        Insecticides – kills insects (that prey on the plant)

The use of pesticides can increase food production (crop yield) as it removes things that decrease crop yield.

Pesticides:

Pros:

-        Increases efficiency

-        Immediate results

-        Gets rid of pests completely  

Cons:

-        Bioaccumulation (gets into food chains and causes damage, organisms at the top of the food change have the largest amount of accumulated chemicals)

-        Have to apply continuously/repeat applications

-        Pests can develop a resistance

-        Not specific enough, can kill other non targeted organisms

Biological (organic) pest control: natural predators of the pest are used, they eat the target pest and leave other wildlife unharmed (e.g ladybirds can be used to control aphids)

Pros:

-        Specific targets

-        Lasts a long time

-        Cost effective: can be expensive to set up but once set up takes little effort to sustain

Cons:

-        Possibility of predator eating another pest/organism

-        Can take time, not as fast as using chemical pesticides

-        Reduces the number of pests but doesn’t completely wipe out