The Dirty Dozen app is handy to have on your iPhone for trips to the grocery store. It's free and simple: it lists the 12 fruits and vegetables that contain the most pesticide residue.
I'm lucky to live in a part of the country where there are farms nearby and farmer's markets that run all summer and into the fall. When winter arrives, however, I still have to keep berries in the fridge or my fruit-loving offspring may revolt. With the Dirty Dozen app, I have a quick reference to help me decide when to buy organic.
I'm no health nut and sometimes have a hard time justifying spending more for organic produce. I figure eating a piece of nonorganic fruit is better than not eating it at all. But given the rate at which my children can consume strawberries, blueberries, and raspberries, I worry about their exposure to pesticides. Since downloading the Dirty Dozen app, I now make an effort to buy organic strawberries and blueberries, since both made the Dirty Dozen list.
The app also includes the Clean 15, which lists 15 popular fruits and vegetables with the lowest amounts of pesticide residue. And the Full List ranks 53 produce items, which may help you decide whether to buy organic on items in between the Dirty Dozen and the Clean 15.
Tap on the Guide button and you'll find a useful FAQ page with information about produce and pesticides. The Dirty Dozen app is made by the Environmental Working Group, whose mission is "to use the power of public information to protect public health and the environment."
In related news, if you are willing to spend $1.99, the Harvest app shows pesticide levels of fruits and vegetables, along with advice on how to pick the best piece of produce and how best to store it.