Appendix B. Notes on the biology of the observed microfungi on Andromeda polifolia and Vaccinium oxycoccos.
On Andromeda polifolia
1. Ceuthospora sp. (Fungi imperfecti). Eriksson (1974b) suggested that the plurilocular stromata of the Ceuthospora type that have been noticed on some ericaceous hosts may belong to a polyphagous taxon C. latitans (Fr.) Höhn. with Vaccinium vitis-idaea as its main host. Infection of leaves takes place in autumn when pycnia mature. Over wintering pycnia are formed the subsequent year (own observations).
2. Epipolaeum andromedae (Rehm) Arx (Pyrenomycetes, Asc.). A common parasitic fungus; host-specific on A. polifolia (Eriksson 1974a). Infection takes place in early summer. The ascocarps mature the following year (own observations).
3. Eupropolella vaccinii (Rehm) Höhn. (Discomycetes, Asc.). A polyphagous snow blight fungus, although some physiological specialization has been demonstrated by Kurkela (1974). Spores are released in autumn, vegetative spread by mycelial growth during winter, ascocarps mature the following autumn. May lead to extensive host mortality (Kurkela 1974) however rarely observed on A. polifolia (own observations).
4. Godronia andromedae P. Henn. (Discomycetes, Asc.). Host-specific on A. polifolia (Eriksson 1970). Infection by conidia takes place during rainy periods in summer, while infection by ascospores takes place in early summer. The asexual stage Topospora andromedae (P. Henn.) B. Erikss. is readily formed on the current annual shoots. Leaves remain on infected shoots and ascocarps start to develop on the dying, still attached leaves. Sporulation takes place 2–3 years after infection, generally on detached leaves (Barr 1968, own observations). May cause extensive host mortality (own observations).
5. Lophodermium intermissum Starb. (Discomycetes, Asc.). Host-specific on A. polifolia (Eriksson 1970). Biology similar to L. melaleucum (see further below; own observations).
6. “Phacidium” andromedae Fr. (Fungi imperfecti). A common conidial taxon host-specific on A. polifolia (Eriksson 1974b). Mature pycnia are found both in the autumn and in spring. Infection of current annual leaves and shoots was observed in early summer, however infection also seems to take place in autumn (own observations).
7. Protoventuria andromedae (Rhem) Barr (Pyrenomycetes, Asc.). Host-specific on A. polifolia (Barr 1968, Eriksson 1992). Biology similar to P. elegantula (see further below; own observations).
8. Seimatosporium sp. (Fungi imperfecti). Acervuli of Seimatosporium type were reported by Eriksson (1974b) on A. polifolia. Both taxonomy and biology remains unknown.
On Vaccinium oxycoccos
1. Coleophoma empetri (Rostr.) Petr. (Fungi imperfecti). Polyphagous on ericaceous hosts. Eriksson (1974b) failed to find any morphological differences between pycnia from different Fennoscandian hosts, which does not exclude the existence of physiological specialization. Infects shoots and leaves. Infection takes place in early summer. Over winters as immature pycnia or mycelium. Pycnia mature the following year (Shear et al. 1931, Caruso and Ramsdell 1995, own observations).
2. Exobasidum rostrupii Nannfeldt (Basidiomycetes). Host-specific on V. oxycoccos, causes annual lesions on leaves of the current annual shoot (Nannfeldt 1981). Infection takes place after over wintering in early summer (own observations).
3. Gnomonia setacea (Pers.: Fr. Ces. & De Not. (Pyrenomycetes, Asc.). Polyphagous on various lignoses. V. oxycoccos is the only ericaceous species affected in Fennoscandia (Eriksson 1974a), whereas other species of the subgenus Oxycoccos are attacked in North America (Shear et al. 1931). Mature fruit bodies are only formed on dead 2-yr-old leaves. It is unclear whether this species is necrotrophic or, as claimed by Shear et al. (1931) saprophytic.
4. Godronia cassandrae Peck (Discomycetes, Asc.). Polyphagous both on ericaceous species and various lignoses (Eriksson 1970) although physiological differentiation has been demonstrated (Smerlis 1968). The asexual stage Topospora obturata (Fr.) B. Erikss. causes extensive damage. Conidia are released during rainy periods throughout the summer, while spores are released in early summer, infecting both the current annual growth and older leaves. Infected leaves turn grayish brown after snow melt, remain attached during the following summer, and fruit bodies develop the third year (Shear et al. 1931, Caruso and Ramsdall 1995, own observations). Disease is favored by nitrogen fertilization, high humidity, prolonged periods of flooding and high temperatures (Caruso and Ramsdall 1995). Extensive host mortality frequently occurs in years following rainy autumns and winters with a thick snow cover (own observations).
5. Lophodermium melaleucum (Fr. ex Fr.) De Not. (Discomycetes, Asc.). Polyphagous on Vaccinium spp. (Eriksson 1970). The biology is similar to the closely related Lophodermium oxycocci (Fr.) Karst. which in Fennoscandia only infects V. oxycoccos, but represents a main disease in cranberry cultivations in North America (Caruso and Ramsdell 1995). Ascospores are released during rainy periods with a peak in the middle of the summer when leaves of the annual shoots are infected. Apothecia mature the following year (Caruso and Ramsdell 1995, own observations).
6. Mycosphaerella minor (Karst.) Johans. (Pyrenomycetes, Asc.). Common and polyphagous on most ericaceous species (Eriksson 1974a). Ascocarps mature in early summer infecting the current annual growth and in particular the shoot (own observations).
7. Physalospora vaccinii (Shear) Arx & Muller (Pyrenomycetes, Asc.). Host-specific on V. oxycoccos (Eriksson 1974a). Infection takes place throughout the growing season with highest frequencies later in the season (Caruso and Ramsdell 1995). Fruit bodies are formed on dead leaves during the following year, or later (own observations).
8. Protoventuria elegantula (Rehm) Barr (Pyrenomycetes, Asc.). Polyphagous on Vaccinium spp. (Eriksson 1992). Spores are released in early summer; lesions start to appear on current annual leaves in autumn. Fruit bodies are formed the following year, causing brown lesions on senescing leaves. Maturation takes place the following year; may cause premature leaf shedding (Caruso and Ramsdell 1995, own observations).
LITERATURE CITED
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Caruso, F. L., and D. C. Ramsdell, editors. 1995. Compendium of blueberry and cranberry diseases. The American Phytopathological Society, St. Paul, Minnesota, USA.
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Nannfeldt, J. A. 1981. Exobasidium, a taxonomic reassessment applied to the European species. Symbolae Botanicae Upsaliensis 23:1–72.
Shear, C. L., N. E. Stevens, and H. F. Bain. 1931. Fungus disease of cultivated cranberry. United States Department of Agriculture, Washington, D.C., Technical Bulletin 258, 58 pp.
Smerlis, E. 1968. The occurrence and pathogenicity of forms of Godronia cassandrae in Quebec. Canadian Journal of Botany 46:597–599.