No, there's no need to get rid of the plant.
Mildew is a signthat it's unhappy as much as anything else. One cause is dryness at the roots (probably not a problem this year) and the other is too much rain.
Gather up the leaves as they fall, and next year, at the first sign of mildew, spray every couple of days with a mix of one part milk to nine parts water until it's clear.