Pyracantha Diseases: Dieback, Fire Blight, and Scab

Pyracantha (firethorn) is valued for its vibrant berries and evergreen foliage, but it is prone to several serious diseases. Recognizing symptoms early allows for effective intervention.

Botryosphaeria Dieback and Canker

Symptoms: Leaves wilt and die as branches are slowly killed. Small, sunken cankers enlarge over time. Wood beneath cankers is discolored. Trees cankered near the base will die.

Pathogen: Botryosphaeria spp.

Management: Prune infected branches well below the canker. Remove severely infected trees. Protect trees from drought stress and winter injury.

Fire Blight

Symptoms: Twigs, branches, and leaders wilt and blacken, especially during flowering. Affected twigs may bend into a shepherd's crook. Blackened flower parts remain attached. Cream-colored bacterial ooze may appear on cankers in wet spring conditions. No fungal fruiting structures are present.

Pathogen: Erwinia amylovora (bacterium)

Management: Plant resistant cultivars: 'Mojave', 'Shawnee', 'Yunan'. Avoid planting infected material. Remove severely infected plants. During dry dormant weather, prune infected branches at least 4 inches below the canker. Disinfect pruning tools frequently.

Scab

Symptoms: Velvety, olive-green spots form on leaves, fruit, and stems. Leaves and fruit drop prematurely.

Pathogen: Spilocaea pyracanthae (syn. Fusicladium)

Management: Plant resistant cultivars: 'Bella', 'Duval', 'Flava', 'Fiery Cascade', 'Government Red', 'Prostrata', 'Rutgers', 'Shawnee', 'Santa Cruz Prostrata'. Avoid sprinkler irrigation. Apply fungicide in spring and at regular intervals until weather dries.