A few questions. Did you save seed potatoes from your own crop or buy in new ones?
Does the leaf rattle when you shake it? (A symptom of leaf roll virus)
Actually if these are first year growth from new seed potatoes then you need to do nothing, it should not affect the cropping. Just do not save any seed potatoes from them and make sure you remove all the spuds when you dig them out.
Not sure it is leaf roll virus myself.