Bacteria

Acute oak decline

Description

Acute Oak Decline (AOD) is an emerging disease affecting oak trees (Quercus spp.). The disease primarily affects pedunculate oak and sessile oak, but other oak species can also be affected. Most affected trees are mature, but younger ones with trunk diameters of 10-12 cm have also been recorded. It can lead to the death of oak trees within four to six years of symptom onset. The disease is primarily caused by various agents, particularly bacteria, and is associated with environmental factors that weaken the trees. Sometimes, Agrilus species are present, but they only play a minor role in this type of decline. Generally, the exact cause of this decline remains unknown. AOD was first discovered in the UK; however, similar oak decline diseases have been reported in other parts of the world, making AOD a global concern. There is no cure for AOD, but management strategies aim to reduce the spread of the disease.

Symptom

Identifying AOD involves recognizing dark-colored, weeping fissures on the tree trunks, known as stem bleeds or cankers. These fissures seep black fluid, and the tree canopy can thin as the disease progresses.

Tree Species: Oak

Part of a plant- attacked: Tree trunk, Branch

Pest Category: Bacteria and viruses

Invasive Species: No

Present in EU: Yes