I think you can be pretty sure that non organic veg has been sprayed with pesticides, though organic veg might have been as well (it doesn't mean no pesticides necessarily, it just restricts what kind of pesticides can be used).
Pesticides are poisons to kill pests, not to prolong the life of the produce. Herbicides kill weeds.....
What you are thinking of (I assume) is preservatives, for example washing salad leaves in chlorinated water or coating apples in a waxy substance. These are effective in making the produce last longer but I'm not sure if they would affect organic rating, so it could be possible to buy organic produce that has been treated to make it last longer.
Fruit and veg don't hang around for long in my house as they get eaten up, so I don't know form experience!
I've always believed that PESTicides are to stop PESTS and not for any other purpose. I cannot really say whether the fruit and Vegies last longer than the ones I get from my garden and from my friends and neighbours.I do know that the fruit I have actually been buying this past year has all been very tasty,in beautiful condition and also has lasted very well.Just like the stuff I have NOT paid for!
I think that fruit and veg are sprayed with chemicals to make them last longer. I don't know what the effects are though. These preservatives are in addition to the pesticides that are sprayed on them.
I have often found that the "organic" fruit and veg sold in some so called health food stores looks past its prime, generally because it is so expensive and noone is rushing to buy it. By definition, everything in this world based on carbon is organic hence the study of organic chemistry. Those peddling organic produce should find more appropriate terminology. Any treatments for fruit and veg in this country go through a rigorous testing process to ensure they are not harmful to humans, but it is always a golden rule to wash all before eating because you do not know what they have encountered enroute to market.