Diseases

Bacterial blight of walnut

Juglans regia L.

Walnut blight, caused by Xanthomonas arboricola pv. juglandis, affects all above-ground plant organs, leading to necrosis, fruit rot, and nut drop.

In the reference 83 varieties crop Persian walnut, where this is mentioned in the description.

The primary pathogen of the disease is the bacterium Xanthomonas arboricola pv. juglandis. The pathogen attacks buds, leaves, flowers, and fruits. On fruits, the infection manifests as small black spots that enlarge and cause shriveling of the husk; in the case of early infection, the bacteria penetrate into the kernel, causing it to rot and subsequently leading to fruit drop.

On leaves, the bacterial disease is expressed by the appearance of dark spots, often delimited by veins or located along the margins of the blade, which leads to their deformation. Cankers form on shoots, and affected buds often fail to open and dry out. Under high humidity conditions, exudate may be released on the affected tissue areas in the form of black streaks.

General information about the subject — on the page Bacterial diseases.

Sources8

Varieties of Persian walnut mentioned in the description

Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.