Lately I've been learning a lot about sustainable and organic foods. Generally, organically grown foods are more expensive. Since most of us need to make economic choices when purchasing food the following lists will help you make some choices.
Here is a list of foods that are recommended for organic.
Milk from organic dairies and USDA organic coffee (this also helps save rainforests)
Fruits- strawberries, peaches, nectarines, apples, cherries, grapes and other thin skinned fruits
Vegetables- red peppers, celery, kale, leafy greens, carrots (peeling helps if they are not organic), potatoes and tomatoes
Generally speaking fruits and vegetables with thick skins that are removed are the ones with the least pesticide residues.
Check out the farmer's markets which are just opening in Minnesota for locally grown organic produce.