Cucumber stem rot ?

One of my cucumber plants has rot - I think. The plant is about 5 foot high (in the greenhouse) and has been priducing fruit for several weeks now. I noticed yesterday that where one of the leaves meets the main stem, the stem is rotting and white - this is about 3 feet from the ground. The area affected is about an inch in length. I have removed the leaf. Is there anything else I can do ? Cut off the top of the plant ?  Leave it ? Will the other plants get affected too. Although yesterday was lovely and warm in there, today it is only 14c

If it has a localised fungal infection which hasn't spread to the rest of the plant, it will die above the rotting section anyway, so I would cut it off about 6 inches below the wound, just above a leaf joint.  What you don't want is for the fungus to set fruit (which will be hair-like and almost invisible) as they will release spores into the air which may infect other cucumber plants.  If the rest of the plant is uninfected, it should produce side shoots from some of the junctions between the leaves lower down and the stem.  Select the strongest of these as your new main stem and it may grow OK from there.  Good luck!

Thank you for that - I'll perform the deed in the morning Must be the cold weather The rest of the plant look very healthy so I hope that it will survive.