Brenneria

Brenneria is a genus of phytopathogenic bacteria belonging to the Pectobacteriaceae family. These bacteria are recognized as serious pathogens in arboriculture and forestry, causing localized or systemic infections that target the bark, cambium, and vascular tissues of woody plants.

The disease is classified as a bacterial infection, specifically a type of bacterial necrosis or wetwood. The pathogen survives in the host's tissues and facilitates tissue degradation by producing enzymes that break down cell walls, leading to the characteristic symptoms of lesion formation and sap flow.

Host plants primarily include various species of willow (Salix), which suffer from weeping cankers, and walnut trees (Juglans), which are susceptible to bark necrosis. The economic impact is significant, as the infection can weaken the structural integrity of the trees and eventually lead to dieback or death of the host.

Common signs of the disease include the appearance of dark, wet spots on the bark, exudation of sap from cracks in the stem, and the development of cankers. As the disease progresses, the inner bark and cambium show signs of black staining, and the foliage may exhibit chlorosis followed by wilting.

Disease development is favored by high humidity and the presence of bark wounds, which act as entry points for the bacteria. Effective control strategies involve stringent sanitation practices, such as pruning and destroying infected wood, disinfecting tools to prevent mechanical transmission, and applying copper-based sprays to protect healthy tissue from primary bacterial colonization.