[Grubbypaws]

My celeriac was doing so well until yesterday I noticed deformed leaves on 2 of the plants (picture). I am worried that it might be celery mosaic virus, can any one help? The plants are growing in a raised bed in the sunshine and have been kept well watered during the dry spell. The bed is covered with fleece to deter cats etc. I cannot see any obvious pests on the plants. What should I do? Should I leave them be, cut off the affected leaves or destroy the entire plant?