Phragmidium rubi-idaei

Rust species infecting living leaves of Rubus sp., particularly Rubus idaeus (raspberry).

This study corresponds to the aecial stage: aecia appear on the upper surface of the leaf as powdery ring-shaped pustules surrounding the spermogonia, 0.5 to 1.5 mm across, bright yellow to orange; unlike heteroecious rusts, Phragmidium rubi-idaei completes its life cycle on a single host (autoecious).

Aecia (caeomata) lack a differentiated peridium, producing aeciospores in catenulate chains from basal cells.

Aeciospores globose to subglobose, with a hyaline wall 1.5 to 2.5 µm thick, 18 to 25 µm long, 16.5 to 22 µm wide, uniformly ornamented with blunt verrucae across the entire surface.

Herbarium material available: JTP2574/25.