Solved Please help identify this pest or disease...

Could someone please help me understand what is going wrong with this Erysimum 'Bowles Mauve'?

Affected stems and leaves have this strange purplish colour and the leaves are covered in a white growth. I though at first this might be an infestation of scale insects but when rubbed an airborne powder is released suggesting a fungus.

The only commonly occurring diseases I can find for Erysimum are Downy Mildew and Bacterial Leaf Blight. Neither look a good match for this condition.

Any help gratefully appreciated.

Andy

 

Agree its some kind of fungus if it goes airborne like you say.

Suggest you cut off the affected branches and spray the surrounding plant with one of the Fungus remedies lile Provados Fungus Fighter or Weedols Rose Clear which incorporates a fungus treatment.