No, it is not residue pesticide! That white powdery finish found on blueberries is actually a sign of freshness. The white stuff (called the bloom) is the blueberry's natural protection against the sun and if you can see it, it means the berries have been picked in nice, dry conditions. Blueberries with this dusty white bloom will be firm and plump instead of soft and squishy. They will also have a greater shelf life.