Skip to main contentSkip to footer

Ascochyta Leaf and Pod Spot - Beans

Ascochyta on a bean stem, close up of lesions on a bean leaf & bean leaf symptoms

Pathogen

Fungus

Hosts

Field and broad beans

Symptoms

Brown / black leaf and pod spots with slightly sunken, grey centres and a brown margin, or red/brown and elongated stem lesions. Pycnidia in the lesions release spores which are spread by rain or wind-borne water droplets.

Development

This seed and trash-borne disease infects both winter and spring crops. Spores (conidia) from infected plants can then be further dispersed throughout the surrounding crop by rain splash and wind.

Favourable Factors

Cool, wet weather.

Importance

On beans severe stem lesions can weaken the stem, cause lodging and kill infected plants. Infected beans are usually stained and may be unsuitable for processing or use as seed.

Control

  • Some varieties do offer a degree of tolerance

  • Adopt short crop rotations.

  • Remove crop debris after harvest.

  • Seed should be tested for Ascochyta infection levels before drilling

  • Fungicide seed treatment.

  • Foliar fungicides are available for Ascochyta control

Close up of lesions on a bean leaf

Ascochyta on bean stem