Common Diseases of Poplar Trees: Identification and Management

Poplars are fast-growing trees often used for windbreaks, screening, and timber. However, they are susceptible to several fungal diseases that can cause cankers, dieback, and defoliation. Understanding these diseases helps in early detection and effective management.

Cryptodiaporthe Canker

Symptoms: Initially kills a few twigs, then rapidly forms variously shaped cankers that girdle and kill large branches. Perennial cankers lead to leaf yellowing, premature defoliation, and water sprout formation. During wet weather, green-brown spore masses ooze from cankers, drying to brown. Bark over cankers may crack and fall away, exposing wood to decay fungi. Trees under drought or other stress are most susceptible.

Pathogen: Cryptodiaporthe populea

Management: Irrigate to prevent drought stress in late summer and autumn. Remove severely infected trees.

Cytospora Canker

Symptoms: Twigs and larger branches die. Brown, circular, sunken cankers form on bark. Yellowish spore threads ooze from fruiting structures in cankers during wet weather. Lombardy poplar is highly susceptible.

Pathogen: Cytospora spp.

Management: Prune infected branches well below the canker. Remove severely infected trees.

Rust

Symptoms: Small, yellowish-orange powdery spore pustules on leaf undersides. Spores spread to alternate host, hemlock.

Pathogen: Melampsora spp.

Management: Control usually not recommended as damage is minimal.

Scab and Shoot Blight

Symptoms: Branch tips and young leaves blacken and die rapidly. Olive-green fungal spores develop on dead tissue. Small trees are most susceptible.

Pathogen: Venturia tremulae

Management: Remove severely infected trees.