On 27/08/2017 10:51, Broadback wrote:
It is the time of year attend my raspberry canes, removing last years
and tying up this years growth. I notice a lot (most) have a bright
yellow/orange "stain" on the underside of the leaves. These look like
they could be areas of small insect eggs, what is the most likely cause?
Will it give me problems next year?

Could it be raspberry rust, Phragmidium rubus-idaei?

https://www.rhs.org.uk/advice/profile?PID=775

--
SRH