Diagnosing grey leaf spot in broadleafed crops

A fungal disease (Stemphylium sp.) that is most damaging in wet spring conditions.

Small circular lesions appear in spring on the leaves
Leaflets become distorted by the lesions
In severe cases plants lose all their leaves in spring

What to look for


  • Widespread plant defoliation following warm wet weather.


  • Dark-brown circular lesions that can appear on leaves and then progress to ash-brown necrosis.
  • In severe cases plants lose all their leaves.
  • Brown pockmark lesions on stems and pods.

What else could it be

Condition Similarities Differences
Diagnosing brown spot in narrow-leafed lupins Dark spots on leaflets Solid dark grey spots without ash-grey leaf necrosis
Diagnosing cladosporium leaf spot in narrow-leafed lupins Dark spots on leaflets Lesions are solid dark grey spots, not circular and light grey, and it is more restricted to moist situations.

Where did it come from?

Contaminated stubble
Contaminated stubble
  • Disease incoculum is carried on infected stubble.
  • The disease was first recorded in Western Australia in 1972 and affected nearly all varieties during the 1970. All lupin varieties released since 1979 are believed to carry genes for resistance to grey leaf spot.

Management strategies

Resistant varieties
Resistant varieties
  • Not economically damaging. No control measures recommended.
  • Varieties differ in susceptibility.

Where to go for expert help

DDLS Seed Testing and Certification
+61 (0)8 9368 3721
Page last updated: Friday, 17 April 2015 - 9:10am