Ribes - Blister Rust Leaves have yellow or orange powder on them.
Leaves have yellow coating or powder in spring.
Cluster Cup Rust Cluster cup rust on Ribes americanum Mill. Cluster cup rust on leaves and inflorescence of Ribes americanum Mill. May. The affected Ribes are usually growing in a low lying area, possibly near a swamp. The alternate hosts for this disease are Ribes and sedges. This disease can significantly reduce the yield of black fruited currants.