Which disease is caused by Puccinia striiformis?

The disease caused by Puccinia striiformis is Stripe Rusts of Wheat and Barley. This pathogen is a type of rust fungus specifically known for affecting wheat and barley crops. It produces yellow-orange pustules on the leaves of these plants, which can lead to significant yield losses if not managed properly. Understanding the specificity of this pathogen is crucial for implementing effective disease management strategies, including the use of resistant varieties and appropriate fungicide applications.

The other options mention other diseases or pests that are not directly associated with Puccinia striiformis. Barley yellow dwarf is caused by a viral infection rather than a fungus, while the Bird Cherry-Oat Aphid and the Russian Wheat Aphid are insect pests that affect cereals but are not related to the rust fungi.