|would there be any drawback to using floating row covers
to protect potato plants from insects?
|No problem at all, since the flowers produced on potato plants do not need insect pollination for the tubers to form underground. Be careful with floating row covers over plants that do require pollination (such as tomatoes). If you use them, remove them when the plants are in flower. Floating row covers are great for excluding sucking and chewing insects. Flea beetles and various caterpillars sometimes attack the leaves of potato plants, but their damage is minimal, considering you're only interested in harvesting spuds. So, the bottom line is, unless you what the potato foliage to be without insect damage, you needn't bother protecting the plants with floating row covers.