David Hulbert, a lecturer at Elmwood College in Scotland, said: "Climate change has made the role of the potato roguer even more important.
"Severe frosts are no longer a regular feature of the Scottish winter allowing aphids, which spread severe mosaic and leaf-roll diseases, to survive winter in greater numbers."
Groundkeepers - potatoes surviving from a previous year's crop - were also trouble, as frost failed to kill them, allowing them to grow and contaminate future crops.
Hulbert said: "Crop inspection and roguing play an important part in disease control and the production of high-quality potatoes.
"The financial implications of a crop not achieving the desired certification level can be quite devastating to a farmer's income."
Elmwood College recently completed a two-week potato-roguing course, identifying varieties and crop diseases.
It puts around two dozen students through the course each year, but roguing was "not for the faint hearted", Hulbert said, requiring lots of stamina, a strong back and good eyesight.