Orange Rust

Orange rust affects raspberry and blackberry in the Pacific Northwest, causing damage to bramble crops. Watch for orange-colored pustules on foliage and stems, particularly visible in warm, wet conditions. Remove affected leaves promptly and improve air circulation around plants. Consider resistant varieties where available. Spore spread is worst in wet conditions, so avoid overhead watering. This rust disease spreads readily in moist spring and fall conditions common to Western Washington. Watch foliage closely for early symptoms.

Rust fungi often need two different host plants to complete their life cycle, so identifying and managing the alternate host can break the cycle. Remove heavily infected leaves and dispose of them away from the garden. Improve air circulation to speed leaf drying after rain. Fungicide applications are most effective as preventive treatments before symptoms appear; once pustules are visible, the current infection cycle is already underway.