A few of my runner bean pods have developed a brown powdery streak along the edge. I can't recall seeing that before. It's the sort of colour of broad bean chocolate spot which my broad beans had (but have not previously spread it to other beans I grow). Another plot has a lot of runner bean pods affected - but the broad beans are clean. It's only the pods on the runners, not the leaves, which are the first to discolour on broad beans.
The plants are feeling the heat even though I have been watering them well, so perhaps they are more stressed and susceptible than usual.
Any ideas?
