The Organic Center issued a press release a few months ago First-Ever Estimate of the Dramatic Reduction in Pesticide Risk Possible through the “Organic Option”.

Conventional Fruits and Vegetables with the Highest Pesticide Dietary Risk Index Scores: Domestic

Fruits
Cranberries: 178
Nectarines: 97
Strawberries: 56
Peaches: 54
Pears: 48

Vegetables
Green beans: 330
Sweet bell peppers: 132
Celery: 104
Cucumbers: 93
Potatoes: 74

Conventional Fruits and Vegetables with the Highest Pesticide Dietary Risk Index Scores: Imported

Fruits
Grapes: 282
Nectarines: 281
Peaches: 266
Pears: 221
Strawberries: 78

Vegetables:
Sweet bell peppers: 720
Lettuce: 326
Cucumbers: 317
Celery: 170
Tomatoes: 142

Part of the definition of food labeled organic is that it must be produced without most conventional pesticides and synthetic fertilizers and without antibiotics, growth hormones, genetic engineering or irradiation.