Q&As/Plant Diseases/Raspberry Leaf Rust
These orange spots have appeared on the leaves of my raspberry plants. What are they and do I need to treat for them?
From your description, it would appear that your raspberry plant is infected with raspberry leaf rust which causes bright orange pustules to appear on the leaves.
Unfortunately, this problem can only be prevented rather than cured. Therefore, you must start spraying your plants with a copper compound such as copper oxychloride from early in the season.
When pruning your plants in winter, try to remove as much infected wood as possible and burn. If the raspberries are heavily infected it may be preferable to remove the plants completely and replace with new healthy specimens.