Xanthomonas ricini. [Descriptions of Fungi and Bacteria].

Author(s):  
J. F. Bradbury

Abstract A description is provided for Xanthomonas ricini. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Ricinus communis. DISEASE: Normally a leaf spot disease in which the bacteria are confined to the parenchymatous tissues. The tiny, dark green, water-soaked spots expand and become brownish, angular and necrotic. They may coalesce to form larger necrotic areas and badly infected leaves become chlorotic and may drop. Occasionally petioles and succulent branches have minute oval or linear spots. Sabet (40, 334) obtained atypical symptoms from inoculation of buds. When the leaves opened, the main veins became infected and tissues dependent on infected veins became yellow and flaccid and finally withered. GEOGRAPHICAL DISTRIBUTION: Scattered, more or las world-wide (CMI Map 394, ed. 1, 1962). Extra references include Hong Kong (43, 345), Poland (48, 554b), Zambia and confirmation of Kenya. TRANSMISSION: Probably in wind and rain; it is rapid in wet weather. One report suggests that it is also seedborne (33, 181).

Author(s):  
A. Sivanesan

Abstract A description is provided for Cochliobolus pallescens. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Common on many graminicolous and non-graminicolous hosts. Important cereals and grasses include Eleusine, Hordeum, Oryza, Panicum, Paspalum, Pennisetum, Poa, Saccharum, Setaria, Sorghum, Triticum and Zea economically important dicot hosts include Allium (59, 4867), Arachis (53, 1647), Brassica (66, 3075), Canna, Calendula, Calotropis (44, 1832; 66, 3587), Carica (61, 5129), Cinnamomum, Citrus (68, 843), Coriandrum, Dahlia, Fagopyrum (64, 2425), Gaillardia, Hevea (56, 1257; 67, 5560), Musa (54, 4051), Solanum (50, 3484). DISEASE: Leaf spots of cereals, black point of wheat (44, 102), leaf spot and on stems of rubber (56, 1257; 67, 5560), ear rot of barley (62, 1005), rot of garlic (59, 4867). GEOGRAPHICAL DISTRIBUTION: Australia, Bangladesh, Brunei, Burma, Canada, Colombia, Cuba, Denmark, Egypt, Ethiopia, Fiji, Ghana, Guinea, Hong Kong, India, Indonesia, Iran, Jamaica, Japan, Kenya, Malaysia, Malawi, Nepal, Nigeria, Pakistan, Papua New Guinea, Peru, Philippines, Sierra Leone, Singapore, Solomon Islands, Somalia, Sri Lanka, Swaziland, Sudan, Taiwan, Tanzania, Thailand, Trinidad, USA, USSR, Venezuela, Windward Islands, Zambia, Zimbabwe. TRANSMISSION: By wind-borne conidia and seed-borne.


Author(s):  
E. Punithalingam

Abstract A description is provided for Ascochyta desmazieresii. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Lolium multiflorum and L. perenne. DISEASE: Glume and leaf spot of Italian and perennial ryegrasses. At first leaf lesions start as small purplish or chocolate-brown spots with a distinct red-purple margin. With time these enlarge, become irregular or elliptical, up to 5 mm long and distinctly visible on both sides of the leaves. Finally the centres of older lesions fade to fawn to straw yellow with numerous pycnidia immersed within the leaf tissue on both sides of the leaves but usually abundant pycnidia occur on the lower side. GEOGRAPHICAL DISTRIBUTION: Asia (Japan); Europe (Belgium, Czechoslovakia, Denmark, France, Irish Republic, UK); N. America (USA, California, Oregon, Washington); S. America (Chile, Brazil). TRANSMISSION: No specific studies reported; infection is presumably spread by air-borne conidia in wet weather or heavy dews. The fungus is also probably carried over on crop residues and debris in soil.


Author(s):  
J. E. M. Mordue

Abstract A description is provided for Pestalotiopsis mangiferae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Mangifera indica; also on Anacardium occidentale, Combretum decandrum, Eucalyptus spp., Mimusops spp., Vitis vinifera and many other unrelated host plants. DISEASE: Grey leaf spot of Mangifera indica. The spots vary in size from a few mm to several cm in length, are usually sharply delimited by a dark, raised border, and are silvery grey above and grey to brown below; leaf spots on other hosts are similar. Brown spot or rot of mango fruits is also known. GEOGRAPHICAL DISTRIBUTION: Ghana, Nigeria, Sierra Leone, Tanzania, Uganda, Zaire, Zambia; Bangladesh, Brunei, Burma, Hong Kong, India, Malaysia, Nepal, Sabah, Solomon Islands, Sri Lanka; Australia; Dominican Republic; Venezuela. TRANSMISSION: Inoculation studies with conidia and mycelium have shown P. mangiferae to be a weak parasite, capable of infecting young injured leaves, injured fruits, older uninjured leaves and healthy fruits if in contact with diseased tissue (35, 378; 40, 421). It has been isolated from soil, but the possibility of transmission through soil has not been investigated.


Author(s):  
H. Y. M. Leung

Abstract A description is provided for Cercospora mikaniicola. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Mikania cordata, Mikania micrantha (Asteraceae). DISEASE: Leaf spot and stem canker. GEOGRAPHICAL DISTRIBUTION: Bangladesh, Brazil, Cuba, Colombia, Fiji, Guadalcanal, Hong Kong, India, Jamaica, Malaysia, Niue, Pakistan, Papua New Guinea, Puerto Rico, Samoa, Sierra Leone, Singapore, Solomon Islands, Tuvalu, USA (Florida), Vanuatu. TRANSMISSION: Conidia are presumably air-dispersed but there are no detailed studies.


Author(s):  
B. C. Sutton

Abstract A description is provided for Septoria apiicola. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Apium spp. DISEASE: Leaf spot (or late blight) of cultivated and wild celery and celeriac. On leaves, seeds and seedling roots, reducing yield and causing wastage through blemishes on the edible petioles. Leaf lesions of variable size, 1-6 mm diam., abundant, amphigenous, circular or sometimes vein-limited, confluent when severe, becoming depressed pale brown, margin diffuse. GEOGRAPHICAL DISTRIBUTION: World-wide on Apium spp. TRANSMISSION: Seed-borne (Noble et al., 1958; Sheridan, 1966). Also disseminated by rain-splash, in irrigation water, by contact as well as by animals and workman's tools (Chupp & Sherf, 1960). The pathogen may remain viable in the soil for 18 months in buried celery crop refuse, but for less than 6 weeks in the absence of intact host tissue (42: 82). Viability in infected seed may drop to 2% within 8 months from harvest and both mycelium and conidia can stay alive in seed stored up to 14 months (42: 508; 44, 1332) but not beyond 2 yr.


Author(s):  
A. Sivanesan

Abstract A description is provided for Mycosphaerella populorum. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Populus spp. DISEASE: Septoria canker, leaf spot disease. GEOGRAPHICAL DISTRIBUTION: North America: USA (east and central states). South America: Argentina (CMI Distribution Map 540, 1981). TRANSMISSION: By windborne conidia and ascospores.


Author(s):  
A. Sivanesan

Abstract A description is provided for Mycosphaerella aleuritis. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: Aleurites fordii, A. mollucana, A. montana. DISEASE: Angular leaf spot of tung. GEOGRAPHICAL DISTRIBUTION: Africa: Central African Republic, Malagasy Republic, Malawi, Zaire (probably also Cameroon, Chad, Congo, Gabon). Asia: China, Hong Kong, Japan, Korea, Malaysia, Taiwan. Central America & Caribbean: Cuba, Trinidad. North America: USA. South America: Argentina, Brazil, Paraguay? (CMI Distribution Map 278, ed. 3, 1975). TRANSMISSION: By ascospores and conidia, which are mainly dispersed by rain-splash and wind (45, 1989f).


Author(s):  
H. Y. M. Leung

Abstract A description is provided for Pseudocercospora neriella. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Nerium indicum, Nerium oleander (Apocynaceae). DISEASE: Leaf spot. GEOGRAPHICAL DISTRIBUTION: Argentina, Cyprus, Hong Kong, India, Italy, Israel, Russia, Taiwan, Tanzania, Tunisia, USA (Florida), Venezuela. TRANSMISSION: Not reported, but almost certainly by air-borne or splash-dispersal of conidia.


Author(s):  
D. W. Minter

Abstract A description is provided for Lophomerum ponticum. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Rhododendron ponticum. DISEASE: Leaf spot of rhododendron. In general Lophomerum ponticum appears to be saprophytic. Its ascocarps are usually not produced until the leaves have senesced, become detached and fallen to the litter. Occasionally, however, ascocarps can be found on browned regions of otherwise green leaves, and it seems possible, therefore, that the species is facultatively parasitic. It is important to distinguish this species from Lophodermium vagulum (CMI Descriptions 789) which is the causal agent of a leaf spot disease of chinese rhododendrons, but which does not occur on R. ponticum. GEOGRAPHICAL DISTRIBUTION: Europe (Great Britain), probably much more widespread. TRANSMISSION: By air-borne ascospores in wet or humid weather.


Author(s):  
E. Punithalingam

Abstract A description is provided for Phaeoseptoria vermiformis. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Triticale (Triticum × Secale), Avena (oats) and Triticum (wheat). DISEASE: Leaf spot of Triticale, wheat and oats. Lesions on leaves are irregular to elliptical, light brown to straw yellow. As infection progresses lesions enlarge to form blotches extending to the margins of leaves. GEOGRAPHICAL DISTRIBUTION: East Africa and North America (Mexico, Patzcuaro). TRANSMISSION: Presumably by conidia dispersed by water splash in wet weather or heavy dews. So far the mode of infection under natural conditions and the spread of the disease have not been investigated. It has been suggested that P. vermiformis might persist on native grasses in the field and this could serve as a source of inoculum in addition to the infected stubble or debris left over from previous years crop.


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