understand the reasons for pest control and the advantages and disadvantages of using pesticides.
-where there is a large field of crops all of the same type- monoculture (eg fields barley, wheat, rice)
-where there is monoculture they tend to be susceptible to pests. (variety of living things -> use crop as food source --> reduce productivity of farming -> lose of food and financial impact on farmer)
-to overcome this is to use pesticides -> chemicals -> designed to kill pests.
PROS
-chemicals -> easy to obtain.
-easy to apply
-they are very effective
-CONS-
-many of the chemicals are toxic. will kill other plants and animals and harmful to humans
-biro accumulation -> pesticides build up through the food chain causing problems for animals in the higher tropic levels (DDT)
-mutation in the pest -> resistance to chemicals. -> stronger chemical used which will be harmful to humans or the chemicals might not work so a new chemical would need to be used.
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