According to the EWG, these 12 produce items should be purchased organic. They are called The Dirty Dozen and are listed in order:
- Apples
- Celery
- Strawberries
- Peaches
- Spinach
- Nectarines (imported)
- Grapes (imported)
- Sweet bell peppers
- Potatoes
- Blueberries (domestic)
- Lettuce
- Kale/Collard Greens
The good news is that there is another list called The Clean 15 - they have the lowest levels in pesticides. In order, they are:
- Onions
- Sweet Corn
- Pineapples
- Avocado
- Asparagus
- Sweet Peas
- Mangoes
- Eggplant
- Cantaloupe (domestic)
- Kiwi
- Cabbage
- Watermelon
- Sweet potatoes
- Grapefruit
- Mushrooms
All this information, how the list was determined and more is available from the source: http://www.ewg.org.