Bean rust is a fungal disease that primarily affects runner beans. It can have severe consequences, even perennial, and is very rarely curable. Find out below what to do if your runner beans are affected by bean rust.
Bean rust is a serious fungal disease
Identify bean rust
Bean rust is a serious disease. It is an endoparasite with the Latin name Uromyces appendiculatus. Before you rush into action, you should be absolutely sure that your runner beans really are affected by this serious fungal disease. This is how you recognize bean rust:
- Whitish, yellowish, or brownish convex pustules on leaf surface; the spots are reminiscent of rust from afar, hence the name
- Whitish spots appear on the underside of the leaves
- Spores in the middle of the pustule
- If the infestation is advanced, the spots also appear on the beans
The consequences of bean rust
Bean rust not only looks ugly, it also leads to loss of leaves, smaller beans and, in the worst case, to a complete failure of the harvest.
Prevent bean rust
Like most mushrooms, bean rust likes it warm and humid. Pole beans need a lot of water, but it shouldn't be too moist all the time. It is better to avoid mulching in particularly humid summers. If your bean bed has been attacked by bean rust, you should thoroughly clean the poles used with acid or, better yet, burn them. You should also plant your runner beans in a different bed next year to prevent reinfestation.
Treat bean rust
The bad news: bean rust cannot be cured. There are a few chemicals that kill the fungus, but we don't allow them. Biological means have not yet been tested.
It is also almost impossible to stop the disease, but you can still try. If you discover diseased leaves, remove them immediately! Burn them or throw them in the general waste bin. Never dispose of diseased plant parts on your compost heap!
If your runner beans are already heavily infested and the fruits are showing symptoms, you should remove the plants and burn them or dispose of them properly. Next plant your runner beans elsewhere and use new poles or rope.
tips
It is generally a good idea to use new ropes or poles every year to prevent the spread of any undetected disease.