Yellowing along veins of cucumber leaves

[Lamonicamw]

Any advice would be much appreciated!

 

[roadrunner]

Do all the leaves look like that? As my cucumbers grow the older leaves turn yellow like that, I think it's normal, but if all the leaves look like that, then it's a problem. Probably a nitrogen deficiency (if all leaves look like that)....but that's just a guess.


EDIT: I just took a second look at your pic and noticed how much yellow is in the veins as opposed to the rest of the leaf, so probably something other than nitrogen deficiency. However, still curious what the rest of the plant looks like...

 

[Chuck]

I have never seen that before. Usually the veins stay green and the rest of the leaf turns yellow if it a a virus or a deficiency of some sort. As roadrunner asked, what does the rest of the plant look like?

 

[Lamonicamw]

The plant is young and in my greenhouse. Most of the plant looks OK. The yellowing is primarily at the base of the plant. I did add nitrogen today, Maybe it will help. My concern is the same as Chuck's. Why are the veins turning?

 

[headfullofbees]

Looks like cucumber mosaic virus to me, unfortunately.
If you can, isolate the plant asap as it's carried by insects.
Hope I'm wrong.