Black raspberry leaves with orange pustules on the underside due to orange rust, Arthuriomyces peckianus.

Black raspberry leaves with orange pustules on the underside due to orange rust. Credit: Sandra Jensen, Cornell University, Bugwood.org<br />Licensed under a <a href="https://creativecommons.org/licenses/by-nc/3.0/us/">Creative Commons Attribution-Noncommercial 3.0 License</a>
Credit: Sandra Jensen, Cornell University, Bugwood.org
Licensed under a Creative Commons Attribution-Noncommercial 3.0 License