Bean rust is a fungal disease that primarily affects pole beans. It can have serious consequences, even lasting several years, and is only very rarely curable. Find out below how to act correctly if your runner beans are affected by bean rust.
How do I recognize bean rust on runner beans and how can I prevent it?
Bean rust on pole beans manifests itself in whitish, yellowish or brownish convex pustules on the leaf surface and whitish spots on the underside of the leaf. As the fungal disease progresses, symptoms also appear on the beans. As a preventative measure, pole beans should be grown in alternating beds and poles or ropes should be replaced regularly.
Identifying bean rust
Bean rust is a serious disease. This is an endoparasite with the Latin name Uromyces appendiculatus. Before you act hastily, you should be absolutely sure that your runner beans are indeed affected by this serious fungal disease. This is how you recognize bean rust:
- Whitish, yellowish or brownish convex pustules on the leaf surface; From a distance the stains resemble rust, hence the name
- There are whitish spots 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 unsightly, it also leads to leaf loss, smaller beans and, in the worst case, a complete crop failure.
Prevent bean rust
Bean rust, like most mushrooms, likes it warm and moist. Runner beans need a lot of water, but it shouldn't be too moist for a long time. In particularly wet summers, you should avoid mulching. If your bean bed has been affected by bean rust, you should clean the poles used thoroughly with acid or, better yet, burn them. You should also plant your runner beans in a different bed next year to prevent re-infestation.
Treat bean rust
The bad news: Bean rust cannot be cured. There are a few chemicals that kill the fungus, but we do not allow them. Biological remedies have not yet been tested. Stopping the disease is almost impossible, but you can still try. If you spot diseased leaves, remove them immediately! Burn them or throw them in the trash can. Under no circumstances should you dispose of diseased plant parts in your compost heap!
If your runner beans are already severely infested and symptoms are showing on the fruits, you should remove the plants and burn them or dispose of them professionally. Next, plant your pole beans elsewhere and use new poles or rope.
Tip
It is generally a good idea to use new ropes or poles every year to prevent the spread of any undetected disease.
