Cotoneaster Disease Management: Botryosphaeria Canker and Fire Blight Control

Managing Diseases in Cotoneaster

Cotoneaster faces Botryosphaeria canker and fire blight. Fire blight-resistant cultivars are available, providing a key management tool for this popular landscape genus.

Botryosphaeria Canker

Botryosphaeria causes affected branch leaf wilting/death; branch dieback with dark brown/black pimple-like fruiting structures; dark brown wood under bark. Most susceptible: drought-stressed trees.

Management: Irrigate to prevent drought stress. Prune infected branches.

Fire Blight

Erwinia amylovora kills flowers (remain attached); twig/branch ends brown/black, shepherd's crook curl; dead leaves persist; cankers ooze cloudy liquid in wet spring; branches killed as sunken cankers enlarge into larger wood/main trunk.

Management: Dry dormancy: prune infected branches ≥4 inches below canker base. Disinfest tools frequently. Fertilize carefully (avoid excessive succulent growth). Remove root suckers/water sprouts while small. Remove nearby susceptible unwanted plants.

Fire Blight-Resistant Cotoneaster Cultivars

C. anoenus, C. adpressus, C. canadensis, C. dammeri var. radicans, C. horizontalis, C. microphyllus, C. praecox, C. zabelii.

Integrated Cotoneaster Health Program

Key strategies: cultivar selection for fire blight resistance (8+ resistant cultivars available); drought stress prevention for Botryosphaeria management (irrigation); fire blight sanitation (dormant pruning, tool disinfestation, cultural moderation); and reservoir removal. The availability of resistant cultivars makes fire blight manageable in new plantings, while Botryosphaeria management focuses on cultural stress reduction.