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

5.4 •pest control stops pests eating crops, thus increasing crop yield 

                •pesticides are a chemical pest control, but are poisonous to humans and wildlife, so needs a low level in food

                •biological control is an alternative, using other alternative animals to reduce pests 

                          •the helpful organisms could be predators, parasites or disease-causing   

                          •biological control has a longer-lasting effect and is less harmful however the introduced organisms may become pests themselves 

	Chemical Control	Biological Control
Advantages	•effective  •quick  •specific pests can be killed  •targets specific areas	•reduces to little damage  •no chemicals •more long-term
Disadvantages	•pests can become resistant  •expensive  •cause environmental damage •kills pollinating insects  •may alter the crop •affects food chain	•never completely removes •not immediate  •harder to control in open area •predator may become prey