I scrub potatoes. Other fruit and veg I wash but don't actually use a scrubbing brush on. It's not just pesticides, there are lots of bacteria, like listeria, that grow in soil.
By the way, organic farmers use pesticides too, they are just restricted to using natural (which doesn't necessarily mean safer) rather than artificial pesticides. In fact they may actually use more pesticide because organic pesticides are less effective.
https://www.ocf.berkeley.edu/~lhom/organictext.html
"Contrary to what most people believe, "organic" does not automatically mean "pesticide-free" or "chemical-free". In fact, under the laws of most states, organic farmers are allowed to use a wide variety of chemical sprays and powders on their crops.
So what does organic mean? It means that these pesticides, if used, must be derived from natural sources, not synthetically manufactured. Also, these pesticides must be applied using equipment that has not been used to apply any synthetic materials for the past three years, and the land being planted cannot have been treated with synthetic materials for that period either... A recent study compared the effectiveness of a rotenone-pyrethrin mixture versus a synthetic pesticide, imidan. Rotenone and pyrethrin are two common organic pesticides; imidan is considered a "soft" synthetic pesticide (i.e., designed to have a brief lifetime after application, and other traits that minimize unwanted effects). It was found that up to 7 applications of the rotenone- pyrethrin mixture were required to obtain the level of protection provided by 2 applications of imidan.
It seems unlikely that 7 applications of rotenone and pyrethrin are really better for the environment than 2 applications of imidan, especially when rotenone is extremely toxic to fish and other aquatic life."