Rust stains on bean plants: how to treat bean rust
There is nothing more frustrating than putting your blood, sweat and tears into creating a perfect garden, only to lose the plants to pests and diseases. Although there is a lot of information on pests that affect vegetable plants such as tomatoes and potatoes, fungal diseases of beans are not often mentioned. This article will discuss the causes of rust on bean plants and how to treat the bean rust fungus.
Rust stains on bean plants
Rust stains on bean plants can look like a reddish-brown powder. Sometimes these reddish-brown spots may be surrounded by a yellow halo. The rust fungus can appear on the leaves, pods, shoots or stems of the plant. A bean field affected by a rust fungus may look like it has been burned or badly burned.
Other symptoms of the rust fungus are wilted foliage and small, deformed bean pods. Infection with the rust fungus can lead to other diseases and pest problems. Weakened and diseased plants are often vulnerable to other diseases and pest infestations.
Like many other fungal diseases, rust spots on bean plants are spread by airborne spores. These spores infect plant tissue and then reproduce in hot, humid weather, producing more spores. It is these new spores that appear on the plants as a reddish-brown powder or rust.
In general, these fungus spores are more abundant in the heat and humidity of the summer months. In milder climates, where plants do not die in autumn, these spores can overwinter in plant tissue. They can also overwinter in garden waste.
How to treat the bean rust fungus
As a preventative measure against the rust fungus, many bean growers will add calcareous sulphur to the soil around the bean plants in early spring. There are other ways to prevent rust stains on bean plants:
- Space plants adequately to allow air circulation and prevent infected plant tissue from rubbing against other plants.
- Water bean plants with a slow drip directly into the root zone of the plant. Water splashes can spread fungus spores.
- Keep the garden clean of debris that can be a breeding ground for pests and diseases.
If you think your bean plants have fungus, remove and discard all infected plant tissue. Always use sharp, disinfected pruning shears to prune plants. To reduce the spread of disease, it is recommended that pruning shears be immersed in a mixture of bleach and water between cuts.
After removing infected tissue, treat the entire plant with a fungicide, such as copper fungicide or neem oil. Make sure you get all the surfaces of the plant and also spray the soil around the crown of the plant. Inspect the plant regularly for signs of disease return.
