Bot canker of oak is a disease on stems, branches and twigs of oak trees in Europe and North America. The casual agent of Bot canker of oak is the fungus ''Botryosphaeria corticola''. Bot canker of oak causes lesions and cankers on a wide range of oaks in Europe and most recently live oaks in North America. Some infections were formerly attributed to ''Botryosphaeria stevensii'', but most likely represent infections by ''Botryosphaeria corticola''.
[Alves, A., Correia, A., Luque, J. and Phillips, A., 2004. Botryosphaeria corticola, sp. nov. on Quercus species, with notes and description of Botryosphaeria stevensii and its anamorph, Diplodia mutila. Mycologia 96: 598–613.] ''Botryosphaeria corticola'' is distinguishable from ''Botryosphaeria stevensii'' via ITS rDNA sequencing.
Overview
''Botryosphaeria corticola'' has caused infection of oak trees in Spain,
[Luque J and Girbal, J. 1989. Dieback of cork oak (Quercus suber) in Catalonia (NE Spain) caused by Botryosphaeria stevensii. European Journal of Forest Pathology 19:7–13.] Portugal,
[Santos, M. N. S. 1995. Phytopathological situation of cork oak (Quercus suber L.) in Portugal.IOBC⁄WPRS Bull. 18: 38–42.] Morocco,
[El-Badri, N. and Abadie, M. 2000 and in Algeria (Smahi et al., 2017). Observations on the dynamic of Diplodia mutila Fr. apud Mont. development on the cork-oak, Quercus suber L., in Morocco. Cryptogamic Mycology 21: 235–248.] Italy,
[Franceschini, A., Corda, P., addau, L. and Marras, F. 1999. Observations sur Diplodia mutila, pathoge`ne du cheˆne-lie`ge en Sardaigne. IOBC⁄WPRS Bull. 22, 5–12.] Greece,
[Tsopelas, P., Slippers, B., Gonou-Zagou, Z. and Wingfield, M.J. 2009. First report of Diplodia corticola in Greece on kermes oak (Quercus coccifera). New Disease Reporter 20: 11.] Hungary,
[Vajna L. 1986. Branch canker and dieback of sessile oak (Quercus petraea) in Hungary caused by Diplodia mutila I. Identification of the pathogen. European Journal of Forest Pathology 16:223–229.] and the United States.
[Urbez-Torres, Peduto, F., Rooney-Lantham, S. and Gubler, W.D. 2010. First report of Diplodia corticola causing grapevine (Vitis vinifera) cankers and trunk cankers and dieback of canyon live oak (Quercus chrysolepis) in California. Plant Disease 94(6): 785.][Lynch, S.C., Eskalen, A., Zambino, P.J. and Scott, T. 2010. First report of Bot canker disease caused by Diplodia corticola on coast live oak (Quercus agrifolia) in California. Plant Disease Posted online on 13 Oct 2010, First Look.][Smith, J.A., personal communication, Feb. 2010.]
Bot canker of oak kills trees in natural forests as well as in
cork
Cork or CORK may refer to:
Materials
* Cork (material), an impermeable buoyant plant product
** Cork (plug), a cylindrical or conical object used to seal a container
***Wine cork
Places Ireland
* Cork (city)
** Metropolitan Cork, also known as G ...
plantations. The cork industry in Portugal, Spain, France, Italy, and Morocco has been dealing with declining oaks for several years from biotic and
abiotic factors.
[Brasier, C.M. 1996. Phytophthora cinnamomi and oak decline in southern Europe. Environmental constraints including climate change. Ann Sci For 53:347–358.] This disease has been seen in many cork plantations and is the most important contributor to the decline in the cork industry.
When cork is harvested from the trees, the
cork cambium is exposed creating a wound for the fungus to enter the trunk, and cause disease. Infection of other oaks is most likely through wounds as well. These wounds may be natural wounds, but there is evidence insect damage is involved, especially in coast live oak in California.
''Botryosphaeria corticola'' infects the twigs, branches and stems of oaks and degrades the
cambial tissues. With the degradation of
vascular tissues, the trees display wilting and
dieback
Dieback may refer to a number of plant problems and diseases including:
* Forest dieback caused by acid rain, heavy metal pollution, or imported pathogens
* The death of regions of a plant or similar organism caused by physical damage, such as from ...
symptoms.
Hosts
Europe/North Africa
*Cork oak (''Quercus suber'')
*Holm oak (''Quercus ilex'')
*Kermes oak (''Quercus coccifera'')
*Sessile oak (''Quercus petraea'')
North America
*Canyon live oak (''Quercus chrysolepis'')
*Coast live oak (''Quercus agrifolia'')
*Laurel oak (''Quercus laurifolia'')
*Live oak (''Quercus virginiana'')
*Grape (''Vitis sp. '')
Management
''Botryosphaeria corticola'' can be managed in high value trees, but there is no current management for forest trees.
Carbendazim
Carbendazim is a widely used, systemic, broad-spectrum benzimidazole fungicide and a metabolite of benomyl. It is also employed as a casting worm control agent in amenity turf situations such as golf greens, tennis courts etc. and in some countr ...
and thiophanate-methyl have shown to prevent infection in cork oak in Europe, where it is applied after cork has been harvested. Sanitation is the most common management technique for this disease.
[Luque, J., Pera, J. and Parlade, J. 2007. Evaluation of fungicides for the control of Botryosphaeria corticola on cork oak in Catalonia (NE Spain). Forest Pathology 38: 147-155.] Branches with diseased tissue are pruned off, and heavily infected trees are removed. This prevents future infections by limiting the amount of spores in the area.
Description
''Botryosphaeria corticola'' (''Diplodia corticola'') is a ascomycete fungus. It has both asexual (''Diplodia corticola'') and
sexual reproduction (''Botryosphaeria corticola'') stages occurring naturally.
The asexual
spore
In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...
s (
conidia
A conidium ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non-motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due to the ...
) occur in
pycnidia from conidiogenous cells, without
conidiophores. Pycnidia are dark brown to black, circular, immersed, partially
erumpent and up to 1 mm diameter.
The sexual spores are eight
biseriate ascospores occur inside of asci occur in immersed, partially erumpent, dark brown to black
pseudothecia, up to 1 mm in diameter.
References
{{Taxonbar, from=Q4948831
Fungal tree pathogens and diseases
corticola
Fungi described in 2004
Fungus species