Ascochyta blight

Ascochyta fabae


Burn spot disease of field bean is caused by the fungus Ascochyta fabae. When infection occurs, brownish spots form on leaves and pods. Severe infestation leads to yield losses and reduced quality.

Damage symptoms

Light to dark brown or reddish brown spots appear on the leaves. These become lighter towards the center and are sharply defined. These spots often have dark spore containers (pycnidia) in the center. Dark brown to black, sunken spots can also appear on the pods.

Host plants

Field bean is the only host plant of Ascochyta fabae.


The fungus occurs preferentially in moist locations.

Propagation and transmission

Transmission of the disease occurs through infected seed. However, the pathogen is also introduced into the soil via infected plant residues.

Economic importance

For a long time, common bean blight was considered a major pest. Due to the decline in acreage and the use of tested seed, the pathogen has become much less important.

In the event of severe infestation, yield losses, a reduction in the quality of the harvested crop and contamination of the soil with the pathogen must be expected.

Prevention and control

  • Use of tested and healthy seeds
  • Adherence to a wide crop rotation on heavily infected sites

Last updated: 13.03.2024

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