Minor foliar diseases
Grey leaf spot (Stemphylium botryosum) causes brown circular lesions on leaves which with age can expand and become ash-grey often causing premature defoliation. Brown ‘pockmark’ lesions can occur on stems and pods. In severe cases complete defoliation can occur. Current varieties carry effective genes for resistance and the disease is uncommon in WA.
Cladosporium leaf spot (Cladosporium sp.) causes dark grey circular spots on flowers and leaves of lupin plants in warm and wet conditions. Drier spring conditions rapidly reduce disease spread and yield reductions rarely occur.
Grey mould (Botrytis cinerea) causes large sunken lesions on stems or branches and infects and causes abortion of flowers and pods. Mature lesions are characterised by grey, fuzzy mould. Favoured by warm humid spring conditions or dense crop canopies. This disease may be more common in albus lupins but rarely causes economic damage in WA lupin crops.
Powdery mildew (Erysiphe polygoni) affects all lupin species. Typically it is seen as a white powdery growth on leaves, stems and pods. Serious crop damage has not been reported in WA.