4:34 p.m.
Many thanks to those of you who wrote back about the distinctively striped
foliage disease of aspen.
Mike Schomaker (also in Colorado) said that he has seen this as an early
stage of ink spot, caused by Ciborinia whetzelii. He was initially puzzled
until he saw sclerotia forming in the symptomatic leaves later in the
season. I rechecked a few descriptions of the disease, and an initial
zonate pattern is mentioned briefly but I have not found a photograph of
it.
After incubating my "tiger blight" for 3-4 days, the zonation is beginning
to fade and sclerotia have begun to form (see photo below). So, it looks
like Mike is correct (congratulations, although I was starting to like the
name tiger blight!). I will follow the development in nature through the
summer and see whether it begins to look more like ink spot as usually
pictured.
Thomas Kirisits wrote about Septotinia podophyllina and referred me to
Butin. Luckily I have his books. In Forstpathologie für Studium und
Praxis (1973), he describes and presents a drawing of Ringfleckenkrankheit
der Pappel, caused by Sclerotinia (Septotinia) podophyllina. It makes
somewhat round lesions with concentric banding. It has an asexual stage
(unlike Ciborinia) with large conidia and produces apothecia in the
spring. In Krankheiten der Wald- und Parkbäume (1983), he refers to the
pathogen as Septotinia populiperda. This fungus is closely related to
Ciborinia (both in Sclerotiniaceae) so it is not surprising it might
produce similar symptoms.
Risto Jalkanen referred to a similar disease of unknown etiology he has
seen on Salix caprea. Perhaps it is caused by a related fungus.
Several people suggested the possibility of leaf miner (insect) damage. It
certainly is reminiscent of leaf miner damage (which we actually saw at the
same site), but we (including entomologist Tom Eager) are convinced that it
is not leaf miner.
Thanks again to all who kindly wrote back with assistance or just
excitement!
(See attached file: tiger_incubated_spots_2.jpg)
Jim Worrall
US Forest Service
Rocky Mountain Region
Forest Health Management
216 N. Colorado St.
Gunnison CO, 81230
(970) 642-1166 desk
(970) 390-2352 cell
(970) 642-1919 fax
6:33 a.m.
Dear Jim et al,
greetings from Canada. Our friend Bill Jacobi at Colorado State University has a beutiful
pictutre/image and information on this disease (I like your proposed name "Tiger
Blight"). Please, see the following link:
http://www.invasive.org/browse/detail.cfm?imgnum=5366785
All the best.. Cheers..
Simon
********************************************************************************
Dr. Simon F. Shamoun
Research Scientist/ Chercheur Scientifique
Adjunct Professor- UBC, TRU & SFU/ Professeur Associe- UBC, TRU et SFU
Canadian Forest Service Service canadien des
forêts
Pacific Forestry Centre Centre de foresterie du Pacifique
506 West Burnside Road 506, chemin Burnside ouest
Victoria, BC Victoria, (Colombie-Britannique)
CANADA V8Z 1M5 CANADA V8Z 1M5
Tel.: (250) 363-0766 (Office); (250)
363-0715 (Laboratory)
Fax: (250) 363-0775
E-mail: sshamoun(a)nrcan.gc.ca
http://cfs.nrcan.gc.ca/regions/pfc
http://cfs.nrcan.gc.ca/directory/sshamoun
***************************************************************************************
________________________________
From: rg70200-forpath-bounces(a)lists.iufro.org on behalf of James Worrall
Sent: Mon 14/07/2008 10:34 AM
To: rg70200-forpath(a)lists.iufro.org
Subject: [IUFRO RG 7.02 FORPATH] "tiger blight" -- -- = ink spot?
Many thanks to those of you who wrote back about the distinctively striped
foliage disease of aspen.
Mike Schomaker (also in Colorado) said that he has seen this as an early
stage of ink spot, caused by Ciborinia whetzelii. He was initially puzzled
until he saw sclerotia forming in the symptomatic leaves later in the
season. I rechecked a few descriptions of the disease, and an initial
zonate pattern is mentioned briefly but I have not found a photograph of
it.
After incubating my "tiger blight" for 3-4 days, the zonation is beginning
to fade and sclerotia have begun to form (see photo below). So, it looks
like Mike is correct (congratulations, although I was starting to like the
name tiger blight!). I will follow the development in nature through the
summer and see whether it begins to look more like ink spot as usually
pictured.
Thomas Kirisits wrote about Septotinia podophyllina and referred me to
Butin. Luckily I have his books. In Forstpathologie für Studium und
Praxis (1973), he describes and presents a drawing of Ringfleckenkrankheit
der Pappel, caused by Sclerotinia (Septotinia) podophyllina. It makes
somewhat round lesions with concentric banding. It has an asexual stage
(unlike Ciborinia) with large conidia and produces apothecia in the
spring. In Krankheiten der Wald- und Parkbäume (1983), he refers to the
pathogen as Septotinia populiperda. This fungus is closely related to
Ciborinia (both in Sclerotiniaceae) so it is not surprising it might
produce similar symptoms.
Risto Jalkanen referred to a similar disease of unknown etiology he has
seen on Salix caprea. Perhaps it is caused by a related fungus.
Several people suggested the possibility of leaf miner (insect) damage. It
certainly is reminiscent of leaf miner damage (which we actually saw at the
same site), but we (including entomologist Tom Eager) are convinced that it
is not leaf miner.
Thanks again to all who kindly wrote back with assistance or just
excitement!
(See attached file: tiger_incubated_spots_2.jpg)
Jim Worrall
US Forest Service
Rocky Mountain Region
Forest Health Management
216 N. Colorado St.
Gunnison CO, 81230
(970) 642-1166 desk
(970) 390-2352 cell
(970) 642-1919 fax
9:01 p.m.
I run a pathology diagnostic lab at the Great Lakes Forestry Centre in Sault Ste. Marie,
Ontario and sure enough, I just got a sample of C. whetzelii in and the symptoms are
exactly the same. I don't remember noticing before. Guess I pay most attention to
the sclerotia. Learn something new every day
Chuck Davis
-----Original Message-----
From: rg70200-forpath-bounces(a)lists.iufro.org
[mailto:rg70200-forpath-bounces@lists.iufro.org] On Behalf Of James Worrall
Sent: Monday, July 14, 2008 10:35 AM
To: rg70200-forpath(a)lists.iufro.org
Subject: [IUFRO RG 7.02 FORPATH] "tiger blight" -- -- = ink spot?
Many thanks to those of you who wrote back about the distinctively striped foliage disease
of aspen.
Mike Schomaker (also in Colorado) said that he has seen this as an early stage of ink
spot, caused by Ciborinia whetzelii. He was initially puzzled until he saw sclerotia
forming in the symptomatic leaves later in the season. I rechecked a few descriptions of
the disease, and an initial zonate pattern is mentioned briefly but I have not found a
photograph of it.
After incubating my "tiger blight" for 3-4 days, the zonation is beginning to
fade and sclerotia have begun to form (see photo below). So, it looks like Mike is
correct (congratulations, although I was starting to like the name tiger blight!). I will
follow the development in nature through the summer and see whether it begins to look more
like ink spot as usually pictured.
Thomas Kirisits wrote about Septotinia podophyllina and referred me to Butin. Luckily I
have his books. In Forstpathologie für Studium und Praxis (1973), he describes and
presents a drawing of Ringfleckenkrankheit der Pappel, caused by Sclerotinia (Septotinia)
podophyllina. It makes somewhat round lesions with concentric banding. It has an asexual
stage (unlike Ciborinia) with large conidia and produces apothecia in the spring. In
Krankheiten der Wald- und Parkbäume (1983), he refers to the pathogen as Septotinia
populiperda. This fungus is closely related to Ciborinia (both in Sclerotiniaceae) so it
is not surprising it might produce similar symptoms.
Risto Jalkanen referred to a similar disease of unknown etiology he has seen on Salix
caprea. Perhaps it is caused by a related fungus.
Several people suggested the possibility of leaf miner (insect) damage. It certainly is
reminiscent of leaf miner damage (which we actually saw at the same site), but we
(including entomologist Tom Eager) are convinced that it is not leaf miner.
Thanks again to all who kindly wrote back with assistance or just excitement!
(See attached file: tiger_incubated_spots_2.jpg)
Jim Worrall
US Forest Service
Rocky Mountain Region
Forest Health Management
216 N. Colorado St.
Gunnison CO, 81230
(970) 642-1166 desk
(970) 390-2352 cell
(970) 642-1919 fax
6002
days inactive
6004
days old
rg70200-forpath@lists.iufro.org
2 comments
3 participants
participants (3)
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Davis, Chuck -
James Worrall -
Shamoun, Simon