Peronospora euphorbiae. [Descriptions of Fungi and Bacteria].

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 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 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 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 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 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):  
J. N. Kapoor

Abstract A description is provided for Podosphaera leucotricha. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Malus spp., chiefly on M. pumila (apple), peach (Prunus persica), quince (Cydonia ualgaris) and Photinia spp. also attacked (Hirata, 1966). Also reported on almond fruit (43, 2544). DISEASE: Powdery mildew of apple. GEOGRAPHICAL DISTRIBUTION: Africa (? Kenya, Rhodaia, South Africa, Tanzania); Asia (China, India, Israel, Japan, U.S.S.R.); Australia and New Zealand, Europe (widely distributed) North America (Canada and U.S.A.); South America (Argentina, Brazil, Chile, Colombia, Peru). (CMI map 118). TRANSMISSION: Overwinters on host as dormant mycdium in blossom buds. The role of deistothecia in overwintering is doubtful. Spread by wind-borne conidia (Anderson, 1956).


Author(s):  
P. F. Cannon

Abstract A description is provided for Barrmaelia oxyacanthae, saprobic on wood of various trees. Some information on its dispersal and transmission and conservation status is given, along with details of its geographical distribution (Africa (South Africa), North America (Canada, USA (New Jersey, North Dakota, South Dakota, Vermont, Virginia)), Asia (Georgia, Japan, Kazakhstan (Aktyubinskaya oblast), Pakistan), Europe (Belarus, Belgium, former Czechoslovakia, Finland, France, Germany, Italy, Lithuania, Luxembourg, Netherlands, Norway, Poland, Sweden, Switzerland, Ukraine, UK, former Yugoslavia)). B. oxyacanthae is sometimes found on elm twigs previously gnawed by rabbits.


Author(s):  
J. C. David

Abstract A description is provided for Alternaria zinniae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Ageratum, Aster, Bidens, Calendula, Callistephus, Chrysanthemum, Coreopsis, Cosmos, Dahlia, Gaillardia, Galinsoga, Gerbera, Helianthus, Notonia, Parthenium, Sphaeranthus indicus, Tagetes, Tithonia, Volutarella, Xanthium, Zinnia. Also recorded are a number of non-compositae hosts such as bean (50, 3295), rape (43, 1212b), Clarkia, Hibiscus esculentus (66. 4729), pawpaws (66. 4729) and seeds of tobacco (64, 1748) but these reports should be regarded with some doubt. Simmons (1982) also reports other hosts like Gentiana, Papaver and Reseda. DISEASE: Leaf spot of Zinnia. The fungus attacks the leaves, stems of its host and can cause damping-off of seedlings where both the root and the stems of the plant may be affected. In older plants the fungus attacks the older leaves and then spreads to the younger leaves, and when the attack is severe the spots may become confluent. GEOGRAPHICAL DISTRIBUTION: Africa: Egypt, Ethiopia, Ghana, Kenya, Libya, Malawi, Mauritius, Sierra Leone, South Africa, Sudan, Tanzania, Uganda, Zambia, Zimbabwe. Asia: Brunei, China (Liaoning). India, Indonesia (Borneo), Korea, Nepal, Pakistan. Australasia & Oceania: Australia. Europe: Cyprus. Denmark, France, Germany, Hungary, Italy, Norway, Poland, Portugal, Romania, The Netherlands. Central & North America: Bermuda, Canada, Jamaica, USA (Hawaii, Illinois, South Dakota). TRANSMISSION: On seeds by wind dispersal of airborne conidia.


Author(s):  
J. C. David

Abstract A description is provided for Cercospora cichorii. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Leaf spot of chicory. HOSTS: Cichorium endivia, C. intybus (Compositae). GEOGRAPHICAL DISTRIBUTION: AFRICA: Madagascar, South Africa (DOIDGE, 1950), Sudan, Zambia. NORTH AMERICA: Bermuda, USA (Michigan, New York, South Dakota, Texas, Wisconsin). SOUTH AMERICA: Argentina. ASIA: Azerbaijan, Republic of Georgia, India, Pakistan, Turkmenistan, Uzbekistan. EUROPE: Greece (52: 2856), Romania (66: 4701), Russia, Ukraine. TRANSMISSION: By wind dispersal of airborne conidia.


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).


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