Why is one of my potatoe vines not as thriving as others? See attached photo. Leaves are yellowy and drop all time. Apply lots of fertilisers and compost but still not happy. Getting enough water
Certified GKH Gardening Expert
It appears to be an infection, whether fungal or bacterial. It may just be that it is not as hardy to the infection as the other two.
If a fungicide does not correct the issue, then it may need to be replaced with another healthy specimen.
Here are some articles that will help: