Cankers on Parade

Some common or important canker diseases
Disease Pathogen Fruiting Hosts Comments
Nectria canker Nectria galligena <-superficial red perithecia many hdwds., esp. birches, walnut quintessential target canker; fruits fall-spring
Cylindrocarpon mali <-sporodochia
 Diplodia shoot blight Diplodia pinea (= Sphaeropsis sapinea) pycnidia pines Can cause "collar rot" of seedlings in addition to shoot blight.
  Diplodia scrobiculata This recently segregated species (®) was formerly referred to as D. pinea type B. It is less aggressive than D. pinea. Difficult to distinguish without molecular methods.
Eutypella canker Eutypella parasitica black perithecia embedded in bark maples large flaring canker, fans
Hypoxylon canker
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Hypoxylon mammatum conidia first on mat and pillars, then perithecia in stroma aspens  
 Other cankers on aspen
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Cytospora cankers Leucostoma, Valsa spp. <-perithecia united in small stroma various  
Leucocytospora, Cytospora spp. <-pycnidia united in small stroma
Pitch canker Fusarium circinatum (Fusarium subglutinans f.sp. pini) sporodochia various pines SE epidemic in '70s, to CA in '80s
Scleroderris cankerFIDL icon
Gremenniella (Ascocalyx) abietina <-small brown apothecia red (+jack, Scots) pine, other conifers

Disease can be shoot dieback or canker. There is a complex history of varieties, races and types of the pathogen. Briefly, European and NA races. Gremenniella abietina var. abietina has A (can attack large trees and seedlings) and B (attacks seedlings) types.

Additional unpublished information

Brunchorstia pinea <-pycnidia
Beech bark diseaseFIDL icon Cryptococcus fagisuga <-cottony scale Am. + Eur. beech Scale was introduced
Nectria spp., esp. coccinea var. faginata <-superficial red perithecia
Cylindrocarpon faginatum <-sporodochia
Butternut canker
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Sirococcus clavigignenti-juglandacearum pycnidia butternut, Juglans cinerea; black walnut, J. nigra; heartnut, J. ailantifolia var. cordiformis (introduced to North America) Disease first detected about 1967, killing large numbers of butternut, pathogen apparently non-native but origin unknown
Sirococcus shoot blight  Sirococcus conigenus sensu stricto (= S. strobilinus, Ascochyta piniperda in part) pycnidia Larch (Larix laricina), cedar (Cedrus deodora), and spruces (Picea abies, P. pungens, P. spinulosa, P. contorta) in much of northern hemisphere.  Some reports may be recently segregated species below.
S. piceicola Spruces (Picea abies, P. sitchensis and P. glauca) in western Canada and Switzerland Recently segregated species (®)
S. tsugae Cedrus and Tsuga spp. in western North America from Oregon to Alaska Recently segregated species (®)
Chestnut blight Cryphonectria parasitica perithecia and pycnidia like Cytospora cankers chestnut Introduced, drastically changed eastern forests
Septoria canker  Mycosphaerella populorum   Populus species   
Septoria musiva     
Black knot Apiosporina morbosa pseudothecia on hard black stroma cherries gall covered with stroma

Funny picture "Al, let's use the Binford chainsaw and cut out that canker"
"I don't think so, Tim"

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Last modified 1 Aug, 2008