back to HYPP Pathology
home page

Bacteria, GRACILICUTES, PSEUDOMONADALES, PSEUDOMONADACEAE .

Crops attacked: walnut .

Bacterial blight of walnut

Identification, Description, Biology, Epidemiology, Treatement, Possible misleading, Images

[R]Description
This bacterium attacks the leaves, the twigs and the fruits.
On the leaf blade small black spots occur surrounded by a thin water-soaked halo.
Cankers develop on the young shoots which dry out.
Small water-soaked spots occur on the brou after node formation and expand into large black lesions which causes the fall of the husks.

[R]Biology
The bacterium survives in buds and catkins and shows on the young leaves in spring.
On the fruits infection starts from the stigmata.

[R]Epidemiology
The disease is favoured by humid conditions particularly during the flowering stage.
The pollen of the infected catkins is also an important source of inoculum.

[R]Treatement
Apply copper treatments repeatedly during the flowering stage.

[R]Possible misleading
.

[R] Images

1. Xanthomonas campestris juglandis , Bacterial blight (GARDAN L., INRA)
   Bacterial blight of walnut-tree Canker on twig caused by xanthomonas disease.
   
2. Xanthomonas campestris juglandis , Bacterial blight (GARDAN L., INRA)
   Bacterial blight of walnut-tree Brown necrosis on green twig.
   
3. Xanthomonas campestris juglandis , Bacterial blight (GARDAN L., INRA)
   Bacterial blight of walnut-tree Spots of xanthomonas disease on young fruits.
   
4. Xanthomonas campestris juglandis , Bacterial blight (GARDAN L., INRA)
   Bacterial blight of walnut-tree Hollownecrosis of xanthomonas disease on young fruits.
   
5. Xanthomonas campestris juglandis , Bacterial blight (GARDAN L., INRA)
   Bacterial blight of walnut-tree Transversal section of a walnut showing bacterial necrosis.
   

To read this page in French

HYP3 on line : Species (scientific name), Diseases (common names), Glossary, Crops.

back to HYPP Pathology home page