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Identification of the cause of box blight

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Identification of the cause of box blight

Lead scientist
Dr Béatrice Henricot
Partners
University of Reading
Start date
2000
End date
2002
Keywords

box blight, Cylindrocladium, Volutella, Buxus, pathogenicity

Benefits to gardeners

The project has provided information about the identity of the fungus, which is associated with blight symptoms observed on Buxus spp.

The problem

In late 1994, a new blight disease of box was discovered in a nursery in Hampshire. Until 1997, no new cases were reported when a sudden outbreak of the disease was noticed. Since then, the disease has spread throughout the UK and other European countries.

The symptoms of the disease are dark brown spots on the leaves and black streaks on the stems. As a result of infection, the plants defoliate and dieback ensues.

A species of the fungus Cylindrocladium was isolated from the diseased material. The new disease is distinct from the previously described Volutella blight of box, which causes very similar symptoms but is caused by the fungus Volutella buxi. The incidence of Volutella is relatively constant. It seems to be associated with wounds, particularly those caused by clipping.
 

Approach

The conventional morphological characteristics and the DNA sequence data from three different regions of the genome demonstrated that the species isolated from diseased box plants is a new species of Cylindrocladium, given the name C. buxicola.

No close relationship has been found with other described Cylindrocladium species. It may be that this species has been introduced recently to Europe, where Buxus plants are widely grown, from a geographically isolated area. This spread from a very narrow genetic base would also explain why the population of isolates is homogenous.

Pathogenicity assays on whole plants and cuttings give rise to the same symptoms, indicating that wounding is not necessary for the development of this disease.
 

Further information

Read more on box blight

Read about the studies on the control of Cylindrocladium buxicola using fungicides and host resistance

Read about the evaluation of fungicides for the control of Cylindrocladium buxicola in the field 

References

Henricot, B, Pérez Sierra, A and Prior, C (2000). A new blight disease on Buxus in the UK caused by the fungus Cylindrocladium. Plant Pathology, 49(6): 805. Read the report
Henricot, B & Culham A (2002). Cylindrocladium buxicola, a new species affecting Buxus spp., and its phylogenetic status. Mycologia, 94(6): 980-997.

Pérez Sierra A and Henricot B (2002). Identification of fungal species beyond morphology. Mycologist 16 (2): 42-46.

Henricot B (2003). RHS update. In: LR Batdorf, Caring for box, Sage Press, pp 26-27.
 

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