Try to Buy Organic
Why you should buy organic?
First of all organic produce generally has higher values in vital substances like vitamins and minerals.
Secondly "industrially" produced fruits and vegetables are loaded with pesticides.
If you cannot avoid buying non organic: here is a list of pesticide residue data which help you to see which fruits/veggies do contain more pesticide residue.
List of the fruits/vegetable with highest pesticides