Venturia pirina. [Descriptions of Fungi and Bacteria].

1974 ◽  
Author(s):  
A. Sivanesan
Keyword(s):  
Leaf Litter ◽  
Geographical Distribution ◽  
Primary Infection ◽  
Secondary Infection ◽  
Apple Scab ◽  
Black Spot ◽  
Eriobotrya Japonica ◽  
Venturia Pirina ◽  
Young Growth

Abstract A description is provided for Venturia pirina. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Principally on pear (Pyrus communis) and other Pyrus spp., also recorded from Eriobotrya japonica (loquat) (Herb. IMI). DISEASE: Causes scab or black spot of pear, which results in loss of quantity and quality of fruit. The disease attacks shoots, buds, leaves and fruit, symptoms and aetiology being very similar to those of apple scab caused by V. inaequalis on Malus spp. (CMI Descript. 401). Dark, more or less circular scabs are produced on leaves and fruit, often with some growth distortion. Infection of young wood is more common than with apple scab and causes pale brown blister-like lesions which burst to release conidia in the following year. GEOGRAPHICAL DISTRIBUTION: Worldwide in temperate and subtropical regions wherever pears are grown (see CMI Map 367, ed. 2, 1968). TRANSMISSION: Epidemiology is similar to that of apple scab. The overwintering saprophytic perithecial stage on leaf litter releases airborne ascospores in spring which infect young growth, and secondary infection by conidia dispersed during wet summer weather also occurs. Overwintering lesions on young wood are more frequent than with apple scab and conidia produced by these in the spring can be an important source of primary infection (46, 2061; 47, 849).

Venturia inaequalis. [Descriptions of Fungi and Bacteria].

1974 ◽  
Author(s):  
A. Sivanesan
Keyword(s):  
Geographical Distribution ◽  
Venturia Inaequalis ◽  
Secondary Infection ◽  
Black Spot ◽  
Common Disease ◽  
Pathogen Virulence ◽  
Leaf Surfaces ◽  
Dry Conditions ◽  
Rain Splash

Abstract A description is provided for Venturia inaequalis. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Principally on apple (Malus pumila), and other species of Malus. Also recorded on Pyrus spp., Sorbus spp. Pyracantha, Cotoneaster integerrima, Crataegus oxyacantha, Viburnum, Sarcocephalus esculentus (36, 278) (Herb. IMI). DISEASE: Causes scab or black spot of apple, a common disease which can produce serious losses in both quantity and quality of fruit. The fungus can infect shoots, buds, blossoms, leaves and fruit. Symptoms appear initially as small, dull, pale spots particularly on the underside of leaves in spring. These enlarge as a mass of radiating subcuticular hyphae develops, forming dark circular lesions visible on both leaf surfaces; a slight puckering or blistering effect may also occur. Older lesions turn grey as the infected host tissue is killed. Scab on fruit is usually more conspicuous than on leaves, but varies according to resistance, pathogen virulence etc. Severe lesions may involve most of the fruit and become suberized and cracked, thus allowing entrance of secondam rotting organisms. Early infection of young fruit may cause shedding or distorted growth. On older fruit smaller secondary, lesions (pepper spot) often develop around a large primary scab. Infection of mature fruit may become visible during storage as sunken, black lesions. Lesions on young shoots appear as light brown blister-like swellings. GEOGRAPHICAL DISTRIBUTION: Worldwide wherever apples are grown (CMI Map 120, ed. 3, 1966). TRANSMISSION: The fungus overwinters primarily on leaf litter where the saprophytic sexual (perithecial) stage occurs. In wet spring weather the resulting perithecia release masses of airborne ascospores which infect the susceptible young foliage (42, 204). Dormant overwintering lesions on shoots and bud scales may also occur; these produce conidia which can infect young spring growth. Primary (spring) lesions produce conidia which cause secondary infection of foliage, fruit and shoots during wet summer weather. Conidia are dispersed chiefly by rain splash but may be present in the air near heavily infected trees during dry conditions (40, 757).

Pyrenophora teres. [Descriptions of Fungi and Bacteria].

1973 ◽  
Author(s):  
M. B. Ellis
Keyword(s):  
Geographical Distribution ◽  
Primary Infection ◽  
Secondary Infection ◽  
Growing Season ◽  
Pyrenophora Teres ◽  
Net Blotch ◽  
Floral Bracts

Abstract A description is provided for Pyrenophora teres. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Primarily barley, but also occurs sporadically on wheat, oats and many other Gramineae. DISEASE: Causes net blotch of barley. Primary infection occurs from seed-borne inoculum and produces lesions on the first leaves, which are at first pale but develop into dark spots or streaks later. Secondary infection on older leaves produces pale brown blotches, in which is a network of dark brown lines; these may later coalesce to form irregular leaf stripes. Lesions also occur on the floral bracts. On other hosts the reticulate pattern of the lesions is usually absent. GEOGRAPHICAL DISTRIBUTION: Worldwide; occurs in most barley-producing countries (CMI Map 364, ed. 2, 1968). TRANSMISSION: The disease can be seed-borne as mycelium or conidia, but can also over-winter on crop debris. Perithecia are common on old barley stubble in the spring and ascosporic inoculum can produce much infection (49, 116). Secondary infection by air-borne conidia occurs throughout the growing season.

Phyllachora sacchari. [Descriptions of Fungi and Bacteria].

1978 ◽  
Author(s):  
K. H. Anahosur
Keyword(s):  
Geographical Distribution ◽  
Primary Infection ◽  
Black Spot ◽  
New Guinea ◽  
Saccharum Officinarum ◽  
Tar Spot

Abstract A description is provided for Phyllachora sacchari. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Polytoca macrophylla, Rottboellia exaltata, Saccharum officinarum, S. aegypticum, S. robusta, Sorghum almum, S. bicolor, S. halepense, S. sudanense, S. vulgare and S. vulgare var. saccharatum. DISEASE: Causes tar spot or black spot on leaves. This disease has so far not been reported to be serious. However, in severe cases, leaves dry up (Tarr, 1962). GEOGRAPHICAL DISTRIBUTION: Asia (Bangladesh, India, Malaysia (W. Malaysia, Sabah), New Guinea, Philippines); Europe (Sicily); Africa (Nigeria); S. America (Argentina). TRANSMISSION: Although none has been reported, it appears probable that the ascospores present in the crop debris may act as source of primary infection. The ascospores may also be disseminated by wind or rain.

Pyrenophora avenae. [Descriptions of Fungi and Bacteria].

1973 ◽  
Author(s):  
M. B. Ellis
Keyword(s):  
Geographical Distribution ◽  
Primary Infection ◽  
Secondary Infection ◽  
Seedling Blight ◽  
Secondary Spread ◽  
Leaf Stripe ◽  
Blight Of Oats

Abstract A description is provided for Pyrenophora avenae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Oats (Avena spp.). DISEASE: Leaf stripe, blotch or spot and seedling blight of oats. Seed-borne infection produces a range of seedling symptoms from pre-emergence death to slight spotting or streaking of coleoptiles. Mycelial infection of emerging leaves causes distortion and spotting. Inoculum from primary leaves causes secondary spread to upper leaves, producing light reddish-brown irregular streaks or blotches. Spikelet drop (42, 543) and stem-break (36, 641) may also occur when the disease is severe. GEOGRAPHICAL DISTRIBUTION: Widespread; occurs throughout most oat-growing areas. CMI Map 105, ed. 2, 1966, and in addition in Queensland, Egypt, Angola and Colombia. TRANSMISSION: Primary infection appears to be entirely by seed-borne inoculum, either as conidia or more particularly as mycelium in the outer layers of the seed. Secondary infection is by air-borne conidia. Soil-borne inoculum appears to be unimportant.

Venturia populina. [Descriptions of Fungi and Bacteria].

1976 ◽  
Author(s):  
A. Sivanesan
Keyword(s):  
North America ◽  
Geographical Distribution ◽  
Primary Infection ◽  
Secondary Infection

Abstract A description is provided for Venturia populina. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: Populus spp. DISEASE: Blight or dieback of poplars. GEOGRAPHICAL DISTRIBUTION: Europe and North America. TRANSMISSION: By ascospores and conidia (41, 106). Primary infection by ascospores and secondary infection by conidia.

Elsinoe ampelina. [Descriptions of Fungi and Bacteria].

1974 ◽  
Author(s):  
A. Sivanesan
Keyword(s):  
Geographical Distribution ◽  
North American ◽  
Secondary Infection ◽  
Black Spot ◽  
Leaf Abscission ◽  
General Review ◽  
Splash Dispersal ◽  
Elsinoe Ampelina ◽  
Direct Attack ◽  
Fruit Surface

Abstract A description is provided for Elsinoe ampelina. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Vitis spp., especially varieties of the European grape (V. vinifera) and of some North American grapes including V. rupestris, V. Iabrusca and V. aestivalis. Also on Vitis hybrids, especially those derived from susceptible Vinifera or Rupestris parents (27, 461, Arnaud & Arnaud). For details of susceptibility of cultivated varieties and hybrids see Gaudineau (general review), Arnaud & Arnaud, Jennings (33, 67), Boehm (39, 70), du Plessis, Goyal et al. (51, 2735), Krarajnan et al. (49, 2948), Mirica et al. (50, 2404). For susceptibility of tropical and North American Vitis spp. see Fennell (27, 461). DISEASE: Grape anthracnose, black spot of vine (spot anthracnose etc.), birds eye rot (fruits). General symptoms may include: leaves - curling downwards, laceration or chlorosis of leaf parts and death of entire young leaf; shot-hole and premature leaf abscission; stems - stunting and death of young shoots, deterioration of older shoots and stocks, loss of fruit yield; fruits - loss of young bunches and distortion, splitting, mummification or abscission of berries by direct attack on fruit surface. GEOGRAPHICAL DISTRIBUTION: Widespread in most grape-growing areas where suitable rainfall conditions occur (CMI Map 234, ed. 2, 1967). TRANSMISSION: Initially by splash dispersal of conidia produced from overwintered sclerotia on lesions on stems, petioles or old bunch stalks (du Plessis). Secondary infection from diseased leaves, fruits, etc.

Venturia saliciperda. [Descriptions of Fungi and Bacteria].

1976 ◽  
Author(s):  
A. Sivanesan
Keyword(s):  
Geographical Distribution ◽  
Secondary Infection ◽  
Young Growth

Abstract A description is provided for Venturia saliciperda. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: On Salix spp. DISEASE: Willow scab. GEOGRAPHICAL DISTRIBUTION: Canada, Europe, USA. TRANSMISSION: By air-borne conidia. The fungus overwinters by dormant mycelium in pustules on twigs and releases air-borne conidia in spring which infect young growth. Secondary infection may occur by conidia dispersed during summer.

scholarly journals Reinfection as a cause of complications and relapses in scarlet fever wards

1937 ◽  
Vol 37 (2) ◽  
pp. 153-171 ◽  
Author(s):  
V. D. Allison ◽  
W. A. Brown
Keyword(s):  
Scarlet Fever ◽  
Primary Infection ◽  
Secondary Infection ◽  
Clinical Signs ◽  
Late Complications ◽  
Isolation Method ◽  
Fever Patient ◽  
The Third ◽  
Serological Type ◽  
Mode Of Transmission

1. The term “reinfection” has been defined as the secondary infection of a scarlet fever patient during hospitalization withStr. pyogenesbelonging to a serologically different type from that producing the primary infection.2. Of forty-seven scarlet fever patients nursed in a multiple-bed ward and swabbed twice weekly during their period of isolation, thirty-three (70.2 per cent) became reinfected with a serological type ofStr. pyogenesdifferent from that causing the primary disease.3. In fifteen out of the thirty-three patients reinfected, the reinfection was “latent”, i.e. gave rise to no clinical signs, while in the remaining eighteen the reinfection was “manifest”, i.e. was accompanied by clinical signs or complications.4. Patients nursed in cubicles or in a ward confined to infections with a single serological type did not show reinfection; their convalescence was progressive and there were no late complications.5. The majority of complications occurring during the third week of hospitalization and subsequently, in multiple-bed wards devoted to scarlet fever, are due to reinfection.6. Most reinfections occur during the third week in hospital at a time when patients are as a rule convalescent from their primary infection.7. The most frequent mode of transmission of reinfection appears to be by direct contact of patient with patient.8. Ten instances of “relapse” in scarlet fever (only three in the present series) are quoted; in all of them the patients were nursed in multiple-bed wards. In each instance the “relapse” coincided with the isolation of a fresh serological type ofStr. pyogenesfrom the throat, and must therefore be regarded as a second attack of scarlet fever.9. The various systems of nursing patients in isolation hospitals are discussed and it is suggested that scarlet fever patients should be cubicle-nursed if possible. Failing this they should be nursed by the bed-isolation method in multiple-bed wards. By setting aside small wards it might be possible to keep together patients who are all infected by the same serological type ofStr. pyogenes; the number of such wards would vary with the number (usually three or four) of epidemic types current at the time.

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