http://www.umaine.edu/umext/potatopr...rs-section.pdf
here is one from the university of Maine for potatoes. These kinds of chemicals are sprayed on commercial crops not to stop you from growing your own but to increase their storage life span. Sprouted potatoes won't sell.
Sweet potatoes are also sprayed.
I don't know about banana adulterants but many crops have as many as 50 different chemicals that get used at one time or another from neonics to prevent seed rot, to herbicides to prevent weeds, chemical fertilizers, insecticides, mold and mildew prohibitants, growth regulators. While it improves crop yield and improves the look it is also the reason many people go organic or choose to grow their own. Many times it has nothing to do with cost.