blackberry cane with orange organism
While the orange spores and fungal growths are more typically seen on the leaves, they can also appear on canes.
Because the disease is systemic (in roots as well as canes), no fungicide can treat it. All infected plants must be dug up, bagged, and removed from the site.
If you decide to replant blackberries or other brambles, purchase certified disease-free stock and be sure to remove any wild brambles in the vicinity first, because they are notorious for spreading this disease.