Re: Pieris japonica 'Bonfire,
Kathy N
Hi, Martin,
I'm not sure it is rust - do the spots look/feel like pustules? Rust is typically raised spots on the leaf - the ones on your plant look to be within the leaf? Pieris is typically attacked by two disease - Phytopthora root diseases and leaf spot. Leaf spot is caused by a fungus and it typically appears during wet, rainy weather. You can cut out the affected leaves and spray with a fungicide. Phytopthora is the more serious of the two, caused by a fungus and enters the plant through the roots. Once in the plant, there is no getting it out so the plant must be destroyed, the soil it was in improved, and new plants mulched regularly to keep them healthy and strong. Having said all this, however, Pieris can also show disease-like symptoms if not in ericaceous (acid-loving) conditions. So, I would suggest cutting out all affected bits, make sure it is in the right soil condition, and hope for the best.
Kathy C
Replied: Monday 18th of April 2011 09:01 PM
