Botryosphaeria Dieback
General Information1
Botryosphaeria dieback was formerly called bot canker. The disease is caused by species of fungi within the family Botryosphaeriaceae. These fungi infect a wide range of hosts, they are most commonly associated with diseases of woody plants, such as acacia and eucalyptus.
Fungi Implicated2
- The most common fungal species isolated from grapevine-growing regions worldwide implicated in causing Botryosphaeria dieback are:
⇾Diplodia seriata (teleomorph Botryosphaeria obtusa)
⇾Diplodia mutila (teleomorph Botryosphaeria stevensii)
⇾Neofusicoccum parvum (teleomorph Botryosphaeria parva)
⇾Neofusicoccum australe (teleomorph Botryosphaeria australis)
⇾Neofusicoccum luteum (teleomorph Botryosphaeria lutea)
⇾Botryosphaeria dothidea (anamorph Fusicoccum aesculi)
⇾Lasiodiplodia theobromae (teleomorph Botryosphaeria rhodina)
- Lifecycle:1
⇾The fungus over-winters as pycnidia (small dark ‘pimple-like’ structures) on the outside of diseased wood producing and releasing conidia (spores) throughout the growing season
⇾Conidia are spread by wind and rain splash, disseminating the fungi from vine to vine, and from one part of the vine to another
⇾The disease develops when conidia land on freshly cut or damaged wood from fresh pruning wounds or mechanical damage
⇾The conidia germinate and invade the woody tissue via xylem vessels and damage the vascular system
⇾Cankers form around the initial infection point
⇾Damage to the vascular system causes wood necrosis and dieback
⇾In some species, pseudothecia form on the outside of cankers and produce ascospores. Like conidia, ascospores are disseminated by wind and rain splash and enter the plant via fresh pruning wounds
- Botryosphaeria dieback often presents as lack of spring growth from affected spurs with shoot dieback, bud and xylem necrosis
- The main wood symptom of Botryosphaeria dieback is wedge-shaped perennial cankers, indistinguishable to that of Eutypa dieback or circular to nonuniform central staining of the wood observed in cross-sections of affected wood
- Botryosphaeria dieback shows exterior symptoms similar to esca, only by cutting the trunk is it possible to diagnose the disease
- Botryosphaeria dieback symptoms can appear in the field only 1 or 2 years after infections have occurred, but are mainly observed in mature vineyards (<8 years old)
- Cankers, dieback, and plant death have been recorded in 3- to 5-year-old table-grape vines
References:
1. Botryosphaeria Dieback---identification and management, Charles Sturt University.
2. C. Bertsch M. Ramírez‐Suero M. Magnin‐Robert P. Larignon J. Chong E. Abou‐Mansour A. Spagnolo C. Clément F. Fontaine, Grapevine trunk diseases: complex and still poorly understood, Plant Pathology, Volume62, Issue 2, April 2013, Pages 243-265.
3. Disease P, Gramaje D., Managing Grapevine Trunk Diseases With Respect to Etiology and Epidemiology: Current Strategies and Future Prospects, The American Phytopathological Society 2018;102(1):12-39.
4. WineSicence, Fungi in the grapevine, that’s rotten!, September 7, 2019.
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