Diagnosing Eradu patch in narrow-leafed lupins

Eradu patch is a fungal root disease that causes patches in narrow-leafed lupin crops, but does not affect broad-leaved lupins, wheat or canola. It is most common in northern agricultural area sandplain soils, and has also been identified around Badgingarra, Wongan Hills and Merredin.


Patches have most severely stunted plants nearest the edge and may join into larger irregular patches
Tap roots often have red or brown lesions with the outer layer of the root stripped off

What to look for


  • Roughly circular patches with diameters of 0.5 m to 10 m and distinct edges become apparent in the crop seven to eight weeks after sowing.
  • Patches may have a ‘doughnut’ appearance, with severely stunted or dead plants nearest the edge and less stunted plants near the centre. Patches may coalesce over time into larger irregular patches.


  • Taproots are not usually severed but often have red or brown lesions that strip off the outer layer of the root. Lateral roots can be pinched off by similar coloured lesions.

What else could it be

Condition Similarities Differences
Diagnosing rhizoctonia bare patch in grain legumes Patches of stunted and dying plants. Lateral and taproots are pinched off by dark brown lesions, whereas Eradu patch has red brown lesions that also strip off the root cortex.

Where did it come from?

Contaminated soil
Contaminated soil
  • Eradu patch affects narrow leaved lupins but does not affect sandplain blue, yellow or albus lupins and does not cause conspicuous patches in other crops. Barley may show depressed growth in affected patches.
  • The fungus survives between seasons in the soil.
  • After the break of the season the fungus grows out to infect roots of susceptible plants.
  • Barley is only slightly affected by the disease but is an excellent host that builds up the fungus.

Management strategies

  • Rotating crops effectively manages Eradu patch.
  • Two years of pasture, wheat or canola prior to lupin reduces the severity of the disease but a barley crop prior to lupin increases the severity.
  • Broad-leaved lupins are resistant to Eradu patch.
  • Neither soil cultivation nor fungicide seed dressing will reduce the disease.

Where to go for expert help

DDLS Seed Testing and Certification
+61 (0)8 9368 3721
Page last updated: Friday, 17 April 2015 - 9:11am