Can someone please identify this pest/blight on the leaves my climbing beans?
These leaves are from my Purple Kings - the adjacent Blue Lake beans are less affected. The Purple Kings have lost 50% of their leaves now, and most of the remaining leaves are now diseased. Bean production is okay but far from prolific, possibly just due to the cold.
I have been treating with potassium bicarbonate spray for 2 months, but with no clear evidence if its effectiveness. Would be grateful for any better treatment tips.
I know nothing about specific plant diseases.
So I'm not going to diagnose.
However, if a fungal disease infects I always think that the best response --always -- is to only water the soil and not the leaves.
...and plant a mixture of plant species together.
If you want a label there are many diseases to choose from.
I may plant 2 beans at the one ladder climb but the rest are scattered elsewhere. I may sprinkler-irrigate long and deep once per week (if no rain) with ground (spearpump) water, but the rest of the time I hand water at the base of my plants.
Any leaf or stem symptoms, I cut it off.
This time of year is supposedly the driest but the early morning dew is pervasive and still heavy.
If you continue to have issues with 'french' type beans I find the Roma extremely reliable -- and over Summer, I try not to miss the opportunity to plant the delicious Winged Bean.
I am growing Snow Peas but the harvest isn't worth the effort. No disease -- just poor pickings. Similarly, dwarf or bush beans aren't very productive in my patch.
But Roma...they like it here. Although my Blue Lake are doing fine... as we speak.
Swings and slides.
Any disease warrants euthanasia, I reckon. Since beans grow so quickly there are plenty more in the legume sea. And every patch needs legumes to sexually fixate on the Nitrogen.