Pole bean leaves are split and yellow. Why?
Pole Bean Leaves Split and Yellow
Certified GKH Gardening Expert
There are several reasons this can happen. It could be that the plants are not getting enough water, or a disease like root rot or mosaic virus or blight or, if they are dusty as well, powdery mildew. It could also be that the plants are past their prime and naturally yellowing as they die.
An underwatered plant typically will also be wilted and the ground dry, but if watering does not seem to fix the wilting, then it is likely blight or root rot. Blight and root rot cannot be cured and the plants should be discarded. If you see brown spots on the leaves, this is also an indicator of some kind of blight.
If it has mosaic, the leaves will have patterns on them as well. It is also typically incurable and the plants should be discarded.
Powdery mildew is characterized by powdery substance on the leaves. It can be corrected with fungicide.
When beans are past their prime, they will also yellow, typically from the bottom up. They normally do this after producing beans, but heat can speed this up causing stunted fruit and yellow plants.