Xanthomonas manihotis. [Descriptions of Fungi and Bacteria].

1977 ◽  
Author(s):  
J. F. Bradbury
Keyword(s):  
Geographical Distribution ◽  
Manihot Esculenta ◽  
Bacterial Blight ◽  
Vascular Tissue ◽  
Cassava Bacterial Blight ◽  
Progressive Die ◽  
Leaf Spots ◽  
Planting Material ◽  
Rain Splash ◽  
Infected Material

Abstract A description is provided for Xanthomonas manihotis. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Manihot esculenta. DISEASE: Cassava bacterial blight. The symptoms are unusually diverse, and include spotting, blight and wilt of leaves, wilt and dieback of stems, necrosis of vascular tissue of stems and roots, and exudation of bacterial ooze. The disease may begin with water-soaked angular leaf spots that enlarge and coalesce, forming necrotic areas and eventually causing the leaf to dry and fall. In moist conditions ooze is formed on the lesions. Infection may travel back to the petioles and stems, young stems being particularly susceptible. A progressive die-back may follow. The roots usually remain healthy in appearance, but in some susceptible varieties dry, rotted spots may develop around necrosed vascular strands (Lozano, 1975). When infected material is planted the first symptoms are wilting and dieback of the young shoots soon after emergence. GEOGRAPHICAL DISTRIBUTION: Argentina, Brazil, Colombia, Venezuela, Nicaragua, Nigeria, Ghana, Togo, Cameroon, Zaire, Uganda, Malawi, Madagascar, Mauritius, India, Malaysia, Indonesia, Taiwan. CMI Map 521, ed. 1, 1977. TRANSMISSION: The disease is spread in the field mainly by rain-splash. Dissemination is, therefore, mainly downwind (53, 3724). Insects may also transmit the disease, as does Pseudotheraptus devastans in Zaire (Maraite & Meyer, 1975). The disease overwinters and travels from one area to another in infected planting material. Infested tools may also spread disease, especially as harvesting is accompanied by much cutting (Lozano, 1975).

Xylophilus ampelinus. [Descriptions of Fungi and Bacteria].

1991 ◽  
Author(s):  
J. F. Bradbury
Keyword(s):  
South Africa ◽  
Geographical Distribution ◽  
Bacterial Blight ◽  
Early Spring ◽  
Distribution Map ◽  
Stunted Growth ◽  
Leaf Spots ◽  
Overhead Irrigation ◽  
Sources Of Infection ◽  
Xylophilus Ampelinus

Abstract A description is provided for Xylophilus ampelinus. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: Vitis vinifera. DISEASE: Bacterial blight of the grapevine; 'Tsilik marasi' in Greece; 'Maladie d'Oleron' in France; 'Mel nero' in Italy; 'Vlamsiekte' in South Africa. In early spring buds on infected spurs fail to open or make stunted growth which eventually dies. Affected spurs often appear slightly swollen because of hyperplasia of the cambial tissue. Cracks appear along such spurs and enlarge to form cankers. Young shoots may develop pale yellowish-green spots on the lowest internodes. These expand upwards on the shoot, darken, crack and develop into cankers. Cracks and later cankers also form on more woody branches later in spring. In summer, cankers are often seen on the sides of petioles causing a characteristic one-sided necrosis of the leaf. They may also appear on main and secondary flower and fruit stalks. Leaf spots and marginal necrosis sometimes occur. Gum formation is not necessarily a symptom. GEOGRAPHICAL DISTRIBUTION: South Africa, France, Greece (including Crete), Italy (including Sardinia and Sicily), Spain, Turkey (68, 367). (IMI Distribution Map 531, ed 2, 1986). TRANSMISSION: Bacteria are carried by moisture to wounds, leaf scars and other sites where infection may take place. Primary infection can take place without wounding. Grafting and pruning can cause much spread of the disease. Overhead irrigation contributes to spread and development (51, 551). Observations indicate that sources of infection survive in vines even after removal of visibly infected parts.

AFLP assessment of genetic variability in cassava accessions (Manihot esculenta) resistant and susceptible to the cassava bacterial blight (CBB)

Genome ◽  
1999 ◽  
Vol 42 (2) ◽  
pp. 163-172 ◽  
Author(s):  
Gilda Sanchez ◽  
Silvia Restrepo ◽  
Myriam-Cristina Duque ◽  
Martin Fregene ◽  
Merideth Bonierbale ◽  
...  
Keyword(s):  
Genetic Variability ◽  
Manihot Esculenta ◽  
Bacterial Blight ◽  
Cassava Bacterial Blight

AFLP assessment of genetic variability in cassava accessions (Manihot esculenta) resistant and susceptible to the cassava bacterial blight (CBB)

Genome ◽  
1999 ◽  
Vol 42 (2) ◽  
pp. 163-172 ◽  
Author(s):  
Gilda Sanchez ◽  
Silvia Restrepo ◽  
Myriam-Cristina Duque ◽  
Martin Fregene ◽  
Merideth Bonierbale ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Manihot Esculenta ◽  
Bacterial Blight ◽  
Multiple Correspondence Analysis ◽  
Aflp Analysis ◽  
Resistance Screening ◽  
Base Resistance ◽  
Cassava Bacterial Blight ◽  
Xanthomonas Axonopodis ◽  
Cassava Varieties

Cassava bacterial blight (CBB) is caused by Xanthomonas axonopodis pv. manihotis (Xam). Resistance is found in Manihot esculenta and, in addition, has been introgressed from a wild relative, M. glaziovii. The resistance is thought to be polygenic and additively inherited. Ninety-three varieties of M. esculenta (Crantz) were assessed by AFLPs for genetic diversity and for resistance to CBB. AFLP analysis was performed using two primer combinations and a 79.2% level of polymorphism was found. The phenogram obtained showed between 74% and 96% genetic similarity among all cassava accessions analysed. The analysis permitted the unique identification of each individual. Two Xam strains were used for resistance screening. Variation in the reaction of cassava varieties to Xam strains was observed for all plant accessions. The correlation of resistance to both strains, had a coefficient of 0.53, suggesting the independence of resistance to each strain. Multiple correspondence analysis showed a random distribution of the resistance/susceptibility response with respect to overall genetic diversity as measured by AFLP analysis. A total heterozygosity index was calculated to determine the diversity within clusters as well as among them. Our results demonstrate that resistance to CBB is broadly distributed in cassava germplasm and that AFLP analysis is an effective and efficient means of providing quantitative estimates of genetic similarities among cassava accessions.Key words: amplified fragment length polymorphism, genetic base, resistance screening, Xanthomonas axonopodis pv. manihotis.

Peronospora knautiae. [Descriptions of Fungi and Bacteria].

1994 ◽  
Author(s):  
G. Hall
Keyword(s):  
Downy Mildew ◽  
Geographical Distribution ◽  
Leaf Spots ◽  
Rain Splash

Abstract A description is provided for Peronospora knautiae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Cephalaria transylvanica, Knautia arvensis, K. carpatica, K. caucasica, K. drymeia subsp. drymeia, K. integrifolia, K. godeti, K. montana, K. silvatica, Pterocephalus plumosus, Scabiosa columbaria, S. lucida, S. ochroleuca, Succisa pratensis. DISEASE: Downy mildew of Knautia and Scabiosa species. Leaf spots are violet or brown and sparse. GEOGRAPHICAL DISTRIBUTION: Asia-Temperate: Azerbaijan, Stavropol, Turkmenistan. Europe: Austria, Czechoslovakia, Denmark, Estonia, France, Germany, Italy, Latvia, Lithuania, Norway, Poland, Romania, Russia (Novgorod, Pskov, St. Petersburg, Yaroslavl), Sweden, Switzerland, Ukraine. TRANSMISSION: By conidia which are dispersed by wind or rain-splash.

Xanthomonas campestris pv. corylina. [Descriptions of Fungi and Bacteria].

1987 ◽  
Author(s):  
J. F. Bradbury
Keyword(s):  
Geographical Distribution ◽  
Black Sea ◽  
Bacterial Blight ◽  
Xanthomonas Campestris ◽  
Corylus Avellana ◽  
Leaf Spots ◽  
Water Splash ◽  
Wet Weather ◽  
Stem Cankers ◽  
Sea Area

Abstract A description is provided for Xanthomonas campestris pv. corylina. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Corylus avellana, C. maxima and C. rostrata (syn. C. californica). On inoculation C. colurna is also infected. DISEASE: Bacterial blight or bacteriosis of filbert or hazel nut trees. Leaf spots, bud and twig necroses and stem cankers are produced. The cankers may girdle branches or even trunks of young trees and cause death above. GEOGRAPHICAL DISTRIBUTION: Turkey (Black Sea area 54, 578), Australia (Vict. 60, 6677), England (59, 3913), France (56, 86), Italy (64, 4520), Yugoslavia (37: 125), USA (OR, WA), Chile (culture received at CMI), and apparently USSR (58, 4044). TRANSMISSION: Bacteria overwinter in cankers on branches and in buds, and spread to other parts of the tree in wet weather. Limited spread from tree to tree takes place by water splash. Man is an important vector especially during pruning activities on young trees. He is also responsible for the introduction of the disease into new areas.

Botryosphaeria obtusa. [Descriptions of Fungi and Bacteria].

1973 ◽  
Author(s):  
E. Punithalingam
Keyword(s):  
New York ◽  
Geographical Distribution ◽  
Fruit Rot ◽  
Dark Spot ◽  
Black Rot ◽  
Night Time ◽  
Leaf Spots ◽  
Spore Release ◽  
Botryosphaeria Obtusa ◽  
Rain Splash

Abstract A description is provided for Botryosphaeria obtusa. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Malus and Vitis. Also on Acer, Alnus, Amygdalus, Artemisia, Betula, Citrus, Crataegus, Cupressus, Diospyros, Eriobotrya, Hicoria, Juniperus, Liquidambar, Liriodendron, Lucuma, Magnolia, Melia, Nannorrhops, Nerium, Pinus, Platanus, Prunus, Rhamnus, Ribes, Robinia, Rubus, Salix, Sassafras, Tectona, Ulmus, Viburnum, Yucca. DISEASE: Causes canker and dieback on pomaceous fruits and grapevine but can live saprophytically on dead wood and bark of many woody plants. On apple, B. obtusa is responsible for three diseases: a canker (New York apple tree canker or black-rot canker); frog-eye leaf spot; and black-rot of the fruit. Cankers start as small elliptical areas of discoloured wood, often with a peripheral crack; as they grow the bark becomes roughened and black pycnidial pustules protrude. Diseased branches and twigs can be girdled and killed. Leaf spots begin as small, circular, purple spots which increase in size, developing a light brown centre, the typical 'frog-eye' symptom. Extensive defoliation may result if this stage of the disease is severe. The fruit rot usually commences at a wound or at the calyx as a dark spot, which spreads to envelope the whole fruit. Diseased fruits are firm and black but eventually shrivel and become mummified. GEOGRAPHICAL DISTRIBUTION: Widespread in the temperate areas; Europe, Southern Africa, North and South America, India, Japan, New Guinea, Western Australia, Tasmania, New Zealand. TRANSMISSION: The fungus can over-winter on mummified fruit, cankers, dead twigs and secondary hosts. Conidia and ascospores are mostly dispersed by rain-splash and perhaps by insects. Spore release is affected by relative humidity and temperature and dispersal is stimulated by night-time rain (50, 735).

Phytophthora ilicis. [Descriptions of Fungi and Bacteria].

1991 ◽  
Author(s):  
G. Hall
Keyword(s):  
North America ◽  
Geographical Distribution ◽  
Lower Surface ◽  
Late Winter ◽  
Leaf Fall ◽  
Ilex Aquifolium ◽  
Leaf Spots ◽  
Twig Blight ◽  
Wet Weather ◽  
Rain Splash

Abstract A description is provided for Phytophthora ilicis. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Ilex aquifolium, I. aquifolium f. aureo-marginata. DISEASE: Produces a severe die-back disease (leaf and twig blight) of young and mature holly plants; a facultatively necrotrophic plant pathogen. Symptoms consist of black leaf spots, defoliation, twig die-back and berry infection. Limb and trunk cankers develop inside tissues. Leaf fall begins from the lower branches and progresses upwards producing shafts or pyramids of defoliation. The disease develops well in cool, wet weather but is checked during hot, dry periods. GEOGRAPHICAL DISTRIBUTION: Europe; UK (England), Netherlands. North America; USA (OR, WA). TRANSMISSION: By sporangia borne on sporangiophores which emerge through stomata on the lower surface of leaves. Sporangia are dispersed by rain-splash or by wind and infect leaves via wounds, or twigs via leaf scars. Growth of the mycelium from twigs extends into branches. Berries are infected in late winter and spring. Oospores are formed in leaf spots and in the cortex of dead twigs. They may act as perennating structures, allowing the fungus to survive over the summer and then germinate in cooler weather.

Cercospora carbonacea. [Descriptions of Fungi and Bacteria].

1987 ◽  
Author(s):  
S. Little
Keyword(s):  
Puerto Rico ◽  
North America ◽  
South America ◽  
Sierra Leone ◽  
Geographical Distribution ◽  
Leaf Spot ◽  
West Indies ◽  
Lower Surface ◽  
Leaf Spots ◽  
Rain Splash

Abstract A description is provided for Cercospora carbonacea. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Dioscoria spp. DISEASE: Leaf spot of yams. Causes fairly large, 5-20 mm, angular leaf spots, which are usually delimited by the leaf veins. The dark brown to almost black leaf spots give an almost charred appearance to the leaves, while on the lower surface the spots are grey becoming brown with age. GEOGRAPHICAL DISTRIBUTION: Africa: Ethiopia, Ghana, Guinea, Nigeria, Sierra Leone, Tanzania, Togo, Asia: Burma, India, North America: Canada (Ontario), West Indies (Barbados, Grenada, Jamaica, St. Vincent, Puerto Rico, Trinidad); South America: Venezuela. TRANSMISSION: Presumably by wind-borne and rain-splash dispersed conidia, surviving adverse periods in crop debris.

Cercospora malayensis. [Descriptions of Fungi and Bacteria].

1987 ◽  
Author(s):  
S. Little
Keyword(s):  
Sierra Leone ◽  
Geographical Distribution ◽  
Leaf Spot ◽  
West Indies ◽  
Leaf Surface ◽  
Euphorbia Pulcherrima ◽  
Leaf Spots ◽  
Brown Leaf Spot ◽  
Brown Leaf ◽  
Rain Splash

Abstract A description is provided for Cercospora malayensis. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Hibiscus abelmoschus (musk mallow), H. cannabinus (deccan hemp), H. esculentus (okra), H. fisculatus, H. mutabilis, H. sabdariffa, H. suranensis, Euphorbia pulcherrima, Sphaeralcea cisplaniina. DISEASE: Leaf spot or brown leaf spot of Hibiscus spp. The first symptoms are yellowish patches on the leaf surface. These then become necrotic and gradually expand into irregular greyish brown leaf spots with dark brown to purple borders, surrounded by a pale yellow halo. Ultimately the necrotic areas become shrivelled and crack (30, 445). GEOGRAPHICAL DISTRIBUTION: The fungus is found wherever Hibiscus is cultivated (Chupp & Sherf, 1960). Africa: Ethiopia, Ghana, Mauritius, Sierra Leone, South Africa, Sudan, Tanzania, Uganda, Zimbabwe; Asia: Borneo, India, Indonesia, Japan, Malaysia, Philippines; Australasia: Fiji, Papua New Guinea; North America: West Indies (Jamaica, Trinidad, Cuba); South America: Colombia, Venezuela. TRANSMISSION: Presumably by wind-borne and rain-splash dispersed conidia.

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