Hi class! We talked about this in class, and just came across this in my inbox, thanks to the Sierra Club, so posting it here FYI.
Click on “Read More” for the list of what foods you should try to buy organic (to avoid pesticides) and which it doesn’t matter so much (at least not for your own intake).
Organic on a Budget

In a perfect world all your food purchases would be organic. In our world of unemployment, cutbacks, and tanking 401(k)s, however, compromises often have to be made. Given limited resources, how can green consumers get the most from their shopping dollars?
The “Shoppers Guide to Pesticides” (foodnews.org), by the nonprofit Environmental Working Group, distills 87,000 government studies into two simple lists. The “dirty dozen” are the foods most important to buy in organic form, because conventional versions are so laden with pesticides. The “don’t worry” list is for those you don’t have to fret about–they either face few pest threats (and thus avoid pesticides) or have impermeable skins that are customarily removed prior to eating. –P.R.
THE DIRTY DOZEN: Peaches, Apples, Bell peppers, Celery, Nectarines, Strawberries, Cherries, Kale, Lettuce, Grapes (imported), Carrots, Pears
DON’T WORRY: Onions, Avocados, Sweet corn (frozen), Pineapples, Mangoes, Asparagus, Sweet peas (frozen), Kiwis, Cabbage , Eggplant, Papayas, Watermelons
source:
http://www.sierraclub.org/sierra/200905/grapple.aspx#organic