Peronospora potentillae. [Descriptions of Fungi and Bacteria].

Author(s):  
G. Hall

Abstract A description is provided for Peronospora potentillae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Potentilla argentea, P. aurea subsp. aurea, P. aurea subsp. chrysocraspeda (=P. ternata), P. crantzii, P. pabelliformis, P. gracilis subsp. nuttallii (=P. nuttallii), P. grandiflora, P. nepalensis, P. norvegica, P. norvegica var. hirsuta, P. pulcherrima, P. sterilis. Possibly Fragaria vesca and F. moschata, but see below. DISEASE: Downy mildew of Potentilla species; an obligately necrotrophic plant pathogen. GEOGRAPHICAL DISTRIBUTION: Asia; India, USSR (Uzbekistan). Europe; Czechoslovakia, Denmark, Eire, Finland, France, Germany, Italy, Norway, Poland, Rumania, Sweden, Switzerland, UK (England, Wales, Scotland), USSR (Latvia; RSFSR). North America; USA (Arkansas, Colorado, Idaho, Indiana, Iowa, Kansas, Michigan, New Jersey, Oregon, Texas, Washington State, Wisconsin, Wyoming), Canada (British Columbia, Saskatchewan) TRANSMISSION: By spores ('conidia') dispersed by wind or rain-splash. The role of oospores (if they are usually formed) in disease transmission is unknown.

Author(s):  
G. Hall

Abstract A description is provided for Peronospora sordida. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Scrophularia altaica, S. aquatica, S. auriculata, S. bosniaca, S. californica, S. heterophylla, S. lanceolata, S. marylandica, S. nodosa, S. scopolii, S. umbrosa (=S. alata), Verbascum banaticum, V. blattaria, V. densiflorum (=V. thapsiforme), V. glabratum subsp. glabratum, V. lychnitis, V. nigrum, V. phlomoides, V. phoenicum, V. speciosum, V. thapsus, V. thapsus subsp. crassifolium (=V. montanum), V. virgatum. DISEASE: Downy mildew of Scrophularia and Verbascum, some species of which may be cultivated commercially for their medicinal or ornamental value; an obligately necrotrophic plant pathogen. GEOGRAPHICAL DISTRIBUTION: Asia; USSR (Kirghizia, Turkmenia, Uzbekistan). Europe; Austria, Belgium, France, Czechoslovakia, Denmark, Eire, Finland, Germany, Hungary, Italy, Netherlands, Norway, Poland, Rumania, USSR (Byelorussia, Estonia, Latvia, Lithuania, RSFSR, Ukraine), Sweden, Switzerland, UK (England, Channel Islands, Northern Ireland, Scotland, Wales), Yugoslavia. North America; USA (California, Illinois, Indiana, Iowa, Kansas, Kentucky, Missouri, Nebraska, New York, Ohio, Wisconsin, Virginia). TRANSMISSION: By spores ('conidia') dispersed by wind or rain-splash. The role of oospores (if they are usually formed) in disease transmission is unknown.


Author(s):  
G. Hall

Abstract A description is provided for Peronospora euphorbiae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Euphorbia dulcis, E. paralias, E. peploides, E. peplus, E. platyphylla, E. prostrata, E. serpens, E. serpyllifolia, E. serratula (= E. stricta). DISEASE: Downy mildew of Euphorbia species. Leaf lesions are hypophyllous, but superficial in E. paralias, as it has stomata on the upper surface of its leaves, which curl upwards. GEOGRAPHICAL DISTRIBUTION: Africa: South Africa. Asia-Temperate: Japan. Europe: France, Italy, Majorca, Poland, Romania, Spain, Switzerland, UK (England). North America: USA (South Dakota, Texas). TRANSMISSION: By conidia which are dispersed by wind or rain-splash. The role of oospores in disease transmission is unknown, but they may serve as perennating structures.


Author(s):  
G. Hall

Abstract A description is provided for Peronospora ficariae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Anemone coronaria, Helleborus purpurascens, Ficaria calthifolia, F. ledebourii, F. ficarioides, Ranunculus abortivus, R. acriformis, R. acer, R. acris, R. alpestris, R. auricomus, R. bulbosus, R. carpaticus, R. cassubicus, R. constantinopolitanus, R. crenatus, R. fascicularis, R. ficaria (= Ficaria verna), R. flammula subsp. flammula, R. languinosus, R. lateriflorus, R. lingua, R. montanus, R. nemorosus, R. oreophilus, R. oxyspermus, R. pedatus, R. pennsylvanicus, R. platanifolius, R. polyanthemus, R. pseudoplatanus, R. recurvatus, R. repens, R. sardous, R. scleratus, R. septentrionalis, R. uncinatus (= R. bongardi), R. velutinus. DISEASE: Downy mildew of Ranunculus species, covering the entire leaf undersurface. GEOGRAPHICAL DISTRIBUTION: Asia-Temperate: China, Kazakhstan, Kirgizistan, Russia (Kamchatka), Stavropol, Japan. Australasia: New Zealand. Europe: Austria, Belgium, Belorussiya, Bulgaria, Czechoslovakia, Denmark, Eire, Estonia, Faeroes, Finland, France, Germany, Hungary, Iceland, Italy, Latvia, The Netherlands, Norway, Poland, Romania, Russia (Krym, Moscow, Pskov, Novgorod, St. Petersburg, Saratov, Smolensk, Tambov, Tatariya, Tula, Yaroslavl) Sweden, Switzerland, Ukraine, UK (England, Scotland, Wales, Channel Islands), Yugoslavia. North America; Canada (British Columbia, Que), USA (Alabama, Idaho, Maine, Michigan, Oregon, Wisconsin, Washington State, Wyoming, New York). South America: Argentina, Dominican Republic. TRANSMISSION: By conidia dispersed by wind or rain-splash. The role of oospores in disease transmission is unknown, although they may act as perennating structures.


Author(s):  
G. Hall

Abstract A description is provided for Peronospora oerteliana. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Primula acaulis, P. algida, P. elatior, P. juliae, P. officinalis, P. veris, P. vulgaris. DISEASE: Downy mildew of Primula species. GEOGRAPHICAL DISTRIBUTION: Asia-Temperate: Kazakhstan. Europe: Czechoslovakia, Denmark, Eire, France, Germany, Poland, Romania, Sweden, Switzerland, Yugoslavia, UK (England, Scotland). TRANSMISSION: By conidia which are dispersed by wind or rain-splash. The role of oospores in disease transmission is unknown, but they may have a perennating function.


Author(s):  
G. Hall

Abstract A description is provided for Peronospora conglomerata. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Erodium ciconium, E. cicutarium, E. hoefftianum, Geranium collinum, G. columbinum, G. dissectum, G. lucidum, G. macrorhizum, G. molle, G. ocellatum, G. phaeum, G. pratensis, G. purpureum, G. pusillum, G. pyrenaicum, G. robertianum, G. rotundifolium, G. solanderi, G. sylvaticum, G. transversale. DISEASE: Downy mildew of Geranium species. Conidiophores occur over the entire undersurface of the leaf, which remains small and becomes crinkled and yellowish. In G. pusillum, a weak infection creates only light green patches on affected leaves, but a heavy infection reduces leaf size, and the blade often turns up, causing much tissue damage and subsequent leaf fall (39, 159). GEOGRAPHICAL DISTRIBUTION: Africa: Canary Isles. Asia-Temperate: Armenia, Azerbaijan, Republic of Georgia, Israel, Kazakhstan, Kirgizistan, Uzbekistan, Stravropol, Turkmenistan. Asia-Tropical: India. Australasia: Australia (Qld), New Zealand. Europe: Austria, Czechoslovakia, Denmark, Eire, Finland, France, Germany, Hungary, Italy, Latvia, Lithuania, The Netherlands, Norway, Poland, Portugal, Romania, Russia (Krym, Smolensk, Pskov, Perm, Tatariya), Serbia, Spain, Sweden, Switzerland, Ukraine, UK (England, Scotland), Yugoslavia. North America: Canada (British Columbia), USA (Idaho, Washington State). TRANSMISSION: By conidia dispersed by wind or rain-splash. The role of oospores in disease transmission is unknown, but they may act as perennating structures.


Author(s):  
G. Hall

Abstract A description is provided for Peronospora chlorae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Blackstonia (=Chlora) imperfoliata, B. perfoliata, B. serotina, Centaurium pulchellum, Erythraea centaureum, E. roxburghii, Eustoma russelianum (=Lisianthus russelianus). DISEASE: Downy mildew of Blackstonia and Eustoma. GEOGRAPHICAL DISTRIBUTION: Asia-Temperate: Abkhasiya, Azerbaijan, Republic of Georgia. Asia-Tropical: India. Europe: Denmark, France, Hungary, Italy, The Netherlands, Portugal, Spain, Switzerland, Ukraine, UK (England, Guernsey, Jersey), Yugoslavia. TRANSMISSION: By conidia dispersed by wind or rain-splash. The role of oospores in disease transmission is unknown, but they may act as perennating structures.


Author(s):  

Abstract A new distribution map is provided for Atropellis piniphila (Weir) Lohman & Cash. Hosts: Pine (Pinus). Information is given on the geographical distribution in NORTH AMERICA, Canada (Alberta, British Columbia, Saskatchewan), USA (Alabama, Arizona, Montana, New Mexico, Oregon, South Dakota, Washington State), (Idaho).


Author(s):  
S. M. Francis

Abstract A description is provided for Peronospora sparsa. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Cultivated roses and the following species, Rosa californica, R. centifolia, R. canina, R. chinensis, R. rubiginosa. DISEASE: Downy mildew of rose. Bright red to purple or, less frequently, brown spots develop on the leaves which fall very readily especially if the bushes are shaken gently. A non-parasitic defoliation of unknown origin termed a 'false mildew' has been reported from France (Tramier, 1962). The necrotic spots formed on the leaves are similar at a certain stage to those caused by P. sparsa. Conidiophores and conidia develop on the under surface of the downy mildew spots in high relative humidity. In Europe their production is sparse but in California it is reported as copious (Baker, 1953). In heavy infections stems and flowers (both calyx and petals) become diseased and badly infected and young stems often die back. Flowers and flower buds can be retarded and malformed by the pathogen without visible damage to the leaves (53, 3523). GEOGRAPHICAL DISTRIBUTION: Africa (Egypt, Morocco, S. Africa, Zimbabwe); Asia (Brunei, Iran, Israel, Japan, Mauritius, Philippines); Australasia (Australia, New Zealand); Europe (Austria, Britain (incl. Jersey), Bulgaria, Czechoslovakia, Estonia, France, Germany, Greece, Iceland, Italy, Latvia, Netherlands, Portugal, Poland, Romania, Sweden, Switzerland, Yugoslavia, USSR); N. America (Canada, USA); S. America (Argentina, Brazil). TRANSMISSION: As dormant mycelium in cuttings and plants. It is reported that mycelium can overwinter within infected stems both from warmer countries such as Australia (57, 2154) and Brazil (19, 98) and also from Northern Europe (53, 3523). The role of oospores in disease transmission is less certain. They have been found in leaves and stems (Baker, 1953; Fraymouth, 1956) and flowers (Cuboni, 1888) but their occurrence seems to be sporadic and they do not appear to be of great importance in carrying over the pathogen. The possibility that the disease may be seed borne was suggested by a worker in Poland (7, 325). In 1926 downy mildew was discovered in a commercial nursery near Lublin on one-year-old seedlings of Rosa canina. The seedlings had been raised from seed imported from Vienna and the inference was that the disease came with the seed especially as all seedlings of local origin were healthy. Peronospora sparsa is not listed as a seed pathogen by Neergaard (1977).


Author(s):  

Abstract A new distribution map is provided for Rhizoctonia tuliparum Whetzel & J. M. Arthur. Hosts: Tulip, Iris and other ornamental bulbs and corms. Information is given on the geographical distribution in EUROPE, Austria, Denmark, Finland, Germany, Iceland, Netherlands, Romania, Switzerland, UK, USSR (Moscow district), (Sverdlovsk region), Yugoslavia, NORTH AMERICA, Canada (Ontario), (British Columbia), USA, (Yonkers, New York), (Washington State).


Author(s):  
D. W. Minter

Abstract A description is provided for Coccomyces strobi. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Pinus ayacahuite, P. excelsa [= P. wallichiana] (twig), P. monticola (twig), P. strobus (twig), P. wallichiana. Most records are on P. strobus. DISEASE: Coccomyces strobi is found on recently killed twigs of 5-needle pines. Sherwood (60, 1319) noted that 'since the fungus is nearly ubiquitous and appears soon after the death of the portions of the host on which it occurs, it is tempting to brand it as parasitic'. The twigs on which it occurs are typically rather brittle, suggesting that, like Therrya fuckelii (IMI Description 1297), T. pini (IMI Description 1298) and Colpoma quercinum (IMI Description 942), this fungus may have a rôle in self-pruning of the tree. GEOGRAPHICAL DISTRIBUTION: Canada (British Columbia, New Brunswick, Nova Scotia, Ontario), Hungary, Ukraine, USA (Connecticut, Georgia, Maine, Maryland, Massachusetts, Michigan, Minnesota, Nebraska, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Virginia, Washington, Wisconsin). European records are on Pinus strobus, a native of North America. The fungus is thus most probably also to be a native of North America, which has travelled to Europe with its host. The record from Ukraine is tentative, based on a collection with rather old ascomata. The record from Washington State on P. monticola appears to be the first from west of the Rockies. TRANSMISSION: By air-borne ascospores in humid conditions; in the USA, ascomata containing ascospores have been observed from May to August.


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