symptoms, prevention and natural treatment

Bean grease is a garden disease that is deadly to your plants. This bacterial pathology mainly attacks bean plants, but can spread throughout the vegetable garden. If once installed on your plant, it is condemned, it is possible to avoid its propagation, but also its establishment. Here are all our tips for fighting bean fat.


Two bacterial infectious agents are responsible for this disease. The first is Pseudomonas savastanoi phaseolicola which is the origin of the halo grease. When the plant is affected, it only takes 7 days to see the first symptoms appear. Bean fat grows mainly in humid environments and at temperatures around 25°C.

The second bacterium that comes into play in bean fat is Xanthomonas axonopodis phaseoli. The latter is at the origin of the common fat which has a wide field of proliferation. Indeed, a single strain can cover 200 m² of culture. Like bean fat, it needs a rather warm and humid environment for its development.

The growth of bean fat goes through the following cycle: first, the seed that contains the bacteria will germinate. The bacteria will then go to the seedling and then go to the pods, causing contamination of the new seeds. It is therefore by seeds that the disease spreads.

Pseudomonas-savastanoi-pv-phaseolicola-bean fat from the bean
Credits: Pierre Liotard / GNIS


Depending on the bacteria, the symptoms differ. For the first, necrosis will form on the foliage with a slightly oily texture. On the stems one can observe somewhat oily spots and the pods can ooze a creamy white liquid, even silver.

For the second bacterium, brownish spots with a light yellow halo appear on the leaves. Reddish vertical lines form on the stems then they gradually split, releasing a yellowish liquid that contains the bacteria. Finally, rust-colored spots with a greasy texture may form on the pods.

Prevention actions

To prevent the appearance of bean fat as much as possible, it is necessary to use healthy seeds with a known origin. Plants should be checked regularly to identify as quickly as possible whether they are carriers of the disease. Once the harvest has been carried out, deep tillage must be carried out so as not to leave plant debris on the surface which is conducive to the survival of bacteria. Finally, think about crop rotation so as not to leave the same plants in the same area.