Dying Cucumber

[Biccylova]

The cucumber in our greenhouse has spread to about 8 feet and is trained along the side of the greenhouse about 6 inches from the glass, the 6 feet furthest from the root is nice and green and healthy and still producing cucumbers but nearer the root the leaves have died and gone yellow and the cucumbers are mottled and silvery, whats wrong with it?

[Buenchico]

CMV?
https://www.rhs.org.uk/advice/profile?pid=143