Peronospora violae. [Descriptions of Fungi and Bacteria].

1989 ◽  
Author(s):  
G. Hall
Keyword(s):  
United Kingdom ◽  
Downy Mildew ◽  
Geographical Distribution ◽  
Plant Pathogen ◽  
Colour Change ◽  
Plant Diseases ◽  
Distribution Maps ◽  
Early Stages ◽  
Water Splash

Abstract A description is provided for Peronospora violae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Viola acutifolia, V. arvensis, V. biflora, V. calarata, V. canina, V. cornuta, V. kitaibeliana, V. palustris, V. reichenbachiana, V. riviniana, V. silvestris, V. tricolor, V. tricolor var. arvensis, V. wittrockiana. DISEASE: Downy mildew of Viola spp. (violet and pansy); the fungus is an obligately biotrophic plant pathogen. In the early stages of the disease, a light covering of sporophores may be seen on the undersurface of individual leaves, unaccompanied by a colour change in the leaf. Later yellow patches appear on the upper surface of leaves covering a part of, or the whole lobe corresponding with patches of grey down on the leaf undersurface. Infected leaves eventually turn brown and die. Not all shoots are infected. Mildew first appears in October and progresses rapidly in November if the climate is mild and damp, or more slowly if dry. GEOGRAPHICAL DISTRIBUTION: Asia: USSR (Khazakhstan). Europe: Austria, Belgium, Czechoslovakia, Denmark, Finland, France, Germany (GDR, GFR), Hungary, Italy, Norway, Poland, Rumania, Sweden, Switzerland, United Kingdom, USSR (Estonia, Latvia, Russia, Ukraine, White Russia), Yugoslavia. See CMI Distribution Maps of Plant Diseases 599. TRANSMISSION: Boudier (1987) states that 'spectacular attacks of mildew follow sprinkler watering in dry autumn weather', suggesting that dispersal of spores may occur by a water splash mechanism. No other reports have been published.

Peronospora rubi. [Descriptions of Fungi and Bacteria].

1989 ◽  
Author(s):  
G. Hall
Keyword(s):  
New Zealand ◽  
North America ◽  
Downy Mildew ◽  
Geographical Distribution ◽  
Systemic Disease ◽  
Interspecific Cross ◽  
Plant Diseases ◽  
Red Raspberry ◽  
Outer Cortex ◽  
Distribution Maps

Abstract A description is provided for Peronospora rubi. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Rubus arcticus, R. caesius, R. canadensis, R. canescens, R. chamaemorus, R. cissiburiensis, R. cissoides, R. corylifolius egg. (R. caesius × tereticaulis, R. nemorosus), R. flagellaris, R. fruticosus egg. (R. bregutiensis, R. buschi, R. glandulosus, R. hirtus, R. menkei, R. seebergensis, R. tereticaulis, R. vulgaris), R. idaeus, R. laciniatus, R. leucodermis, R. × loganobaccus (orursinus × ideaus), R. occidentalis, R. parviflorus, R. plicatus, R. procerus, R. spectabilis, R. strigosus, R. sulcatus, R. tuberculatus, R. villosus, R. vitifolius, and certain hybrids, e.g. 'Tayberry' (blackberry cv. Aurora × tetraploid red raspberry), 'Tummelberry' (a 'Tayberry' interspecific cross) and 'Youngberry'. DISEASE: Downy mildew of cane fruits (Rubus spp.), especially blackberry (R. fruticosus agg.), boysenberry (a blackberry × red raspberry cross: the name R. × loganobaccus covers this plant) and raspberry (R. idaeus). The fungus, an obligately biotrophic plant pathogen, occurs on leaves in summer to autumn, producing small, conspicuous, irregularly shaped patches on upper leaf surfaces, starting near the petiole, then following leaf veins. Patches are initially yellow, becoming carmine-red, vinaceous or purple and are bordered by venation. The undersurface of the leaf shows only a pale area with a brownish edge, and brownish discoloration near and alongside veins. Sporophores are sometimes difficult to detect in the dense mat of leaf hairs, but are heaviest on lowest leaves, close to ground level, forming a buff-grey felt. In wild-growing European species of Rubus the fungus occurs exclusively on the leaves. In North America it attacks leaves of cultivated raspberry bushes, and in New Zealand the fruits, sepals and pedicels of boysenberry, causing the fruit to become dry and shrivelled (dryberry disease). Downy mildew has recently become a problem on certain berry cultivars in Eastern England (McKeown, 1988). GEOGRAPHICAL DISTRIBUTION: Africa: South Africa. Asia: USSR (Azerbaijan). Australasia & Oceania: New Zealand. Europe: Czechoslovakia, Denmark, Finland, France, Germany (GFR, GDR), Norway, Poland, Rumania, Sweden, Switzerland, United Kingdom, USSR (Latvia). North America: Canada (British Columbia), USA (IL, MD, OR, WA, WI). See CMI Distribution Maps of Plant Diseases 598. TRANSMISSION: Determined for boysenberry in New Zealand only (61, 4245), where it is a systemic disease confined to the outer cortex parenchyma, keeping pace with cell division at apical meristems. Systemic cane infection is often indicated by red streaking of stems and petioles linking successively diseased leaves on a shoot. Unfolding leaves are invaded during warm wet weather causing typical leaf symtoms. Stores produced on diseased shoots initiate secondary infections of flowers and developing berries. These berries then become an important source of inoculum for new cycles of the disease. They go largely unnoticed, since spores are partially hidden on the split berry surfaces or covered by the sepals. After harvest, infection of developing primocanes continues by internal mycelial growth and spore infection. Oospores form on root surfaces in dead cortex cells and leaves. Soilborne oospores may infect healthy plants established in former sites of infected root crowns.

Phytophthora pseudotsugae. [Descriptions of Fungi and Bacteria].

1989 ◽  
Author(s):  
G. Hall
Keyword(s):  
North America ◽  
Geographical Distribution ◽  
Pseudotsuga Menziesii ◽  
Plant Pathogen ◽  
Root Rot ◽  
Douglas Fir ◽  
Plant Diseases ◽  
Distribution Maps

Abstract A description is provided for Phytophthora pseudotsugae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Pseudotsuga menziesii. DISEASE: Root rot of Douglas fir; the fungus is a facultatively necrotrophic plant pathogen. GEOGRAPHICAL DISTRIBUTION: North America: USA (OR, WA). See CMI Distribution Maps of Plant Diseases 600. TRANSMISSION: Unknown. Presumably soil-borne by zoopores released in favourable conditions.

Peronospora sordida. [Descriptions of Fungi and Bacteria].

1991 ◽  
Author(s):  
G. Hall
Keyword(s):  
New York ◽  
North America ◽  
Northern Ireland ◽  
Downy Mildew ◽  
Geographical Distribution ◽  
Plant Pathogen ◽  
Disease Transmission ◽  
Channel Islands ◽  
Rain Splash

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.

Passalora sojina. [Descriptions of Fungi and Bacteria].

2004 ◽  
Author(s):  
J. C. David
Keyword(s):  
New York ◽  
South Carolina ◽  
Geographical Distribution ◽  
Far East ◽  
Uttar Pradesh ◽  
Plant Diseases ◽  
Mato Grosso ◽  
Distribution Maps ◽  
Aerial Dispersal ◽  
Dead Plant

Abstract A description is provided for Passalora sojina. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Frog-eye leafspot. HOSTS: Glycine hispida, G. javanica, G. max, G. soja, G. ussuriensis (FALEEVA, 1976), Mucuna sp. (CROUS & BRAUN, 2003) (Fabaceae). GEOGRAPHICAL DISTRIBUTION: [CAB International Distribution Maps of Plant Diseases No. 871, Edn. 1 (2002)]. AFRICA: Cameroon, Côte d'Ivoire, Egypt, Gabon, Kenya, Malawi, Nigeria, Zambia, Zimbabwe. NORTH AMERICA: Canada (Ontario), Mexico, USA (Alabama, Arkansas, Delaware, Florida, Georgia, Hawaii, Illinois, Indiana, Iowa, Kansas, Louisiana, Maryland, Michigan, Mississippi, Missouri, New Jersey, New York, North Carolina, Oklahoma, South Carolina, Texas, Virginia, West Virginia, Wisconsin). CENTRAL AMERICA: Cuba, Guatemala. SOUTH AMERICA: Argentina, Bolivia, Brazil (Goias, Maranhao, Mato Grosso, Minas Gerais, Parana, Pernambuco, Piaui, Rio Grande do Sul, Santa Catarina, Sao Paolo), Venezuela. ASIA: China (Fujian, Gansu, Guangxi, Hebei, Heilongjiang, Henan, Jiangsu, Jiangxi, Jilin, Liaoning, Nei Menggu, Sichuan, Yunnan, Zhejiang), East Timor, India (Karnataka, Meghalaya, Sikkim, Uttar Pradesh), Japan, Nepal, Russia (Far East), South Korea, Taiwan. EUROPE: Russia. TRANSMISSION: Seedborne and by aerial dispersal of conidia through wind and rain splash. The fungus also survives in dead plant material and can re-infect living plants (SWEETS, 2001).

Sclerotinia narcissicola. [Descriptions of Fungi and Bacteria].

1991 ◽  
Author(s):  
M. A. J. Williams
Keyword(s):  
New York ◽  
North Carolina ◽  
Geographical Distribution ◽  
Grey Mould ◽  
Ground Level ◽  
Plant Diseases ◽  
West Germany ◽  
Distribution Maps ◽  
Detached Leaves

Abstract A description is provided for Sclerotinia narcissicola. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: Narcissus spp. DISEASE: Smoulder, grey mould. Infection may reduce bulb yield and flower size (55, 3617). Symptoms may include: rot of the bulbs and leaves at ground level, brown lesions on the leaves and flower buds, distortion and failure of emergence. GEOGRAPHICAL DISTRIBUTION: Asia: Iraq, USSR; Australasia: Australia (Tasmania, Victoria), New Zealand; Europe: Channel Islands (Guernsey, Jersey), Denmark, Eire, England, Germany, Northern Ireland, The Netherlands, Norway, Scotland, Sweden, USSR, Wales, West Germany; North America: Canada (British Columbia, NS, Ontario, PEI); USA (North Carolina, New York, Oregon, Virginia, Washington State) (see CMI Distribution Maps of Plant Diseases, No. 315). TRANSMISSION: The disease may come from planting of infected bulbs or from infected soil; sclerotia in the soil may be viable for up to nine months (61, 7053). In vitro conidial suspensions did not cause infection except of wounded or damaged tissue; mycelial inoculation consistently caused lesions on detached leaves and bulb scales (61, 5797).

Valsa sordida. [Descriptions of Fungi and Bacteria].

1998 ◽  
Author(s):  
V. P. Hayova
Keyword(s):  
Czech Republic ◽  
New Zealand ◽  
North America ◽  
South America ◽  
Environmental Stress ◽  
Geographical Distribution ◽  
Plant Diseases ◽  
Republic Of Georgia ◽  
Distribution Maps ◽  
Poplar Trees

Abstract A description is provided for Valsa sordida. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Valsa sordida is usually associated with Valsa canker of poplar twigs. Wounded trees, and trees injured by insects or attacked by other pathogens are more susceptible to infection. Development of Valsa canker is affected by environmental stress (Guyon, 1996; Tao et al., 1984). Poplar canker caused by V. sordida has been studied in different countries (CMI Distribution Maps of Plant Diseases, 1977; Worrall, 1983; Wang et al., 1981) The fungus can be often found in declining poplar stands together with another pathogen of poplar trees, Leucostoma niveum. Valsa sordida may also cause necrosis of willow twigs. HOSTS: Populus spp., Salix spp. and, more rarely, other woody angiosperms. GEOGRAPHICAL DISTRIBUTION: Africa: Morocco. Asia: Armenia, Azerbaijan, China, Republic of Georgia, India, Iran, Iraq, Israel, Japan. Kazakhstan, Korea, Russia (Tatarstan), Turkey, Turkmenia, Uzbekistan. Australasia: Australia (Victoria), New Zealand. Europe: Austria, Belgium, Bulgaria, Czech Republic, Denmark, Estonia, France, Germany, Greece, Ireland, Italy, Netherlands, Norway, Poland, Portugal, Rumania, Russia, Slovakia, Sweden, Switzerland, UK, Ukraine, former Yugoslavia. North America: Canada (Alberta, British Columbia, Nova Scotia, Ontario, Québec, Saskatchewan). USA (California, Colorado, Michigan, Minnesota). South America: Chile. TRANSMISSION: Both conidia and ascospores are air-borne, especially under humid conditions. Yellow or orange exudation of conidia from conidiomata can be often seen after rain.

Sporisorium sorghi. [Descriptions of Fungi and Bacteria].

2002 ◽  
Author(s):  
J. M. Pérez
Keyword(s):  
Sorghum Bicolor ◽  
Central America ◽  
Geographical Distribution ◽  
Plant Diseases ◽  
Panicum Miliaceum ◽  
Distribution Maps ◽  
Infected Seed

Abstract A description is provided for Sporisorium sorghi. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Covered smut or covered kernel smut of sorghum. Development of functional ovaries and anthers is prevented in infected parts of the plants. HOSTS: Panicum miliaceum, Sorghum bicolor, S. dochna, S. halepense, S. plumosum, S. sudanense and S. vulgare (Poaceae). This species has also been recorded from Ischaemum ciliare (VISWANATHAN et al., 2000). GEOGRAPHICAL DISTRIBUTION: Worldwide, see CMI Distribution Maps of Plant Diseases No. 220, edn 4 (1987). In addition it has been recorded from AFRICA: Mauritania (FRISON & SADIO, 1987). CENTRAL AMERICA: Nevis. TRANSMISSION: In addition to dissemination on infected seed, there is evidence that this species can also be spread by air-borne chlamydospores (SHENOI & RAMALINGAM, 1976).

Plasmopara halstedii. [Descriptions of Fungi and Bacteria].

1989 ◽  
Author(s):  
G. Hall
Keyword(s):  
Geographical Distribution ◽  
Latent Infection ◽  
Secondary Infection ◽  
Root Hairs ◽  
Systemic Infection ◽  
Plant Diseases ◽  
Plasmopara Halstedii ◽  
Distribution Maps ◽  
Wide Range ◽  
Putative Origin

Abstract A description is provided for Plasmopara halstedii. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Over 80 hosts from a wide range of genera in the Compositae have been reported, including wild and cultivated species of Helianthus. For lists see Leppik (1966) and Novotel'nova (1977). DISEASE: Downy mildew of sunflower (Helianthus annuus var. macrocarpus); the fungus is an obligately biotrophic plant pathogen. Leaves of infected plants develop chlorotic mottling which spreads from the veins near the petiole across the lamina, and increases in area and intensity as leaves age. Plants become stunted, having thin stems, very much smaller capitula without seeds, and smaller and darker roots. The disease is primarily systemic and mycelium can be found throughout the plant from roots to capitulum and achenes, in all except meristematic tissues. Under humid conditions, a white felt of sporangiophores develops on the undersurface of chlorotic areas. Localized secondary infection of the leaves and heads occasionally develops, resulting in spots, delimited by veins. Such secondary infection may also become systemic. Some infected plants show no disease symptoms, but produce lower yields of poorer quality seeds, which lose vitality and have lower germination rates (latent infection). Cotyledons are also infected causing damping-off in seed beds. A basal gall may also be produced. GEOGRAPHICAL DISTRIBUTION: Plasmopara halstedii is a fungus characteristic of the Americas, its putative origin, It has spread throughout Europe to parts of Africa and Asia, and has recently been reported from New Zealand. See CMI Distribution Maps of Plant Diseases 286. TRANSMISSION: Soil-borne oospores and mycelium (in systemically infected roots) overwinter, infecting subsequent crops. Sporangia form on the surface of infected seedling roots, releasing zoospores which encyst and germinate c root hairs of other seedlings, producing a systemic infection. Sporangia are dispersed by rain-splash from leaves, producing a secondary infection in plants up to the six-leaf stage, but infect only the apical growing points of olde plants. Transmission by oospores in seeds has been responsible for the spread of this fungus around the world, especially since these spores can germinate to produce only a latent infection in the host plant (53, 4545).

Aphanomyces cochlioides. [Descriptions of Fungi and Bacteria].

1989 ◽  
Author(s):  
G. Hall
Keyword(s):  
Geographical Distribution ◽  
Spinacia Oleracea ◽  
Chenopodium Album ◽  
Chronic Phase ◽  
Ground Level ◽  
Plant Diseases ◽  
Distribution Maps ◽  
Aphanomyces Cochlioides ◽  
Point Of Entry ◽  
Root Tissues

Abstract A description is provided for Aphanomyces cochlioides. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Amaranthus blitoides, A. retroflexus, Beta lomatogona, B. patellaris, B. patula, B. trigyna, B. vulgaris, B. vulgaris var. cicla, Celosia argentea, Chenopodium album, Dianthus chinensis, Echinocloa crus-gallii, Escholtzia californica, Gomphrena globosa, Kochia scoparia, K. scoparia var. culta, Lychnis alba, Mollugo verticillata, Papaver rhoeas, Portulaca oleracea, Salsola kali, Saponaria ocymoides, Spinacia oleracea, Tetragonia tetragonioides. DISEASE: Blackroot of sugar beet; the fungus is a facultatively necrotrophic plant pathogen. There is an early acute phase of short duration (causing pre-emergence and post-emergence damping off) and a later chronic phase which may persist throughout the life of the plant. Infection during seed germination is indicated by poor stands with killed seeds remaining in the soil to infect young seedlings emerging elsewhere. Seedling hypocotyls are infected at ground level, a water-soaked area extending up and down the hypocotyl or the upper part of the young taproot from the point of entry. The invaded root or hypocotyl rapidly becomes brownish and then assumes the characteristic jet black discoloration from which the disease derives its name. Soon after, the cortex of the hypocotyl dries, and the stem and hypocotyl shrink, leaving a thin strand of tissue. Oospores are easily seen in the collapsed root and hypocotyl tissue on microscopic examination. The chronic phase first appears on plants in late June to August. A greenish-yellow discoloration of the swollen hypocotyl develops, affected root tissues becoming dark brown, soft, water-soaked, splitting apart and eventually shrivelling. Plants are stunted and lower leaves turn yellow. GEOGRAPHICAL DISTRIBUTION: Asia: Japan. Australasia & Oceania: Australia (Qld). Europe: Austria, Denmark, England, France, Germany (GDR & GFR), Hungary, Ireland, Poland, Sweden, USSR (Russia). North America: Canada (Alberta, NS, Ontario, Quebec), USA (California, Connecticut, Indiana, Michigan, Maine, MT, North Dakota, Ohio, South Dakota, Texas, Washington State, Wisconsin). South America: Chile. See CMI Distribution Maps of Plant Diseases 596. TRANSMISSION: Presumably in soil by oospores originating from sloughed-off root tissues and germinating to produce zoospores. The conditions favouring oospore germination are however largely unknown. Survival may occur on alternative hosts present in the crop, so the disease may be difficult to eliminate. The disease is particularly severe in warm, wet conditions, less so in cool, wet weather.

Plasmopara viticola. [Descriptions of Fungi and Bacteria].

1989 ◽  
Author(s):  
G. Hall
Keyword(s):  
Geographical Distribution ◽  
Secondary Infection ◽  
Plasmopara Viticola ◽  
Early Summer ◽  
Plant Diseases ◽  
Infected Leaf ◽  
Active Growth ◽  
Grape Vine ◽  
Distribution Maps ◽  
Leaf Tissues

Abstract A description is provided for Plasmopara viticola. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Ampelopsis brevipedunculata, A. hederacea, A. heterophylla, A. veitchii, Ampelocissus acetosa, A. latifolia, A. salmonea, Cissus caesia, C. gracilis, C. hypoglauca, C. polyantha, Cordifolia sempervirens, Cinerea sp., Parthenocissus quinquefolia, P. tricuspidata, Solonis robusta, Vitis aestivalis, V. amurensis, V. arizonica, V. berlandieri, V. californica, V. cinerea, V. coignetiae, V. cordifolia, V. girdiana, V. labrusca, V. lanata, V. monticola, V. pagnuccii, V. riparia, V. romaneti, V. rupestris, V. silvestris, V. treleasei, V. vinifera. DISEASE: Grape vine downy mildew; the fungus is an obligately biotrophic plant pathogen. All tissues bearing stomata are infected, becoming discolored, malformed and necrotic. Lesions on affected organs develop a white felt of sporangiophores. Leaves are most susceptible to attack during active growth in early summer, and when very mature in the autumn. Sporangiophores may appear directly on healthy green leaf tissues with no overlying lesion, or as a dense felt under yellow oily lesions on the upper surface (if humidity is high, 5-15 days after infection), or may be absent, leaves presenting only a mosaic of small, angular yellow or dark-red blemishes, limited by the secondary veins (mainly on old leaves in the autumn). During early growth, whole branches are attacked, but later only the extremities of branches are invaded. Infected shoots turn brown, curl up or become hooked at their tips. Nodes are more susceptible to attack than internodes. Tendrils, petioles, inflorescences and bunches also develop similar brown spots and lesions. Bunches are susceptible until the grapes are 5-6 mm diam., after which infection is rare (grey rot followed later by brown rot). Subsequent browning and desiccation of the bunch is caused by penetration of the bunch stalk by mycelium from earlier infections elsewhere. GEOGRAPHICAL DISTRIBUTION: See CMI Distribution Maps of Plant Diseases 221. TRANSMISSION: Oospores present in infected leaf tissues from the previous season's crop germinate in the spring, when air temperatures exceed 12°C and at least 10 mm rain falls in 24 hours, releasing zoospores into water or onto very moist soil from sporangia (64, 2458). Zoospores are projected onto vine leaves near the soil by rain splash, germinate to give hyphae and penetrate tissues via their stomata. Sporangia are liberated in moist air only, are disseminated by air currents, and remain viable for five days in dry air, producing secondary infection sites. Production of sporangia occurs at a relative humidity of 95-100%, and an air temperature of 13-27°C (optimum 18-22°C). Mycelium may overwinter between the bud scales and in diseased leaves, but it has not been established whether this contributes substantially to re-infection of healthy leaf tissues the following spring. There is no evidence for systemic transmission.

Sign in / Sign up

Export Citation Format

Share Document