Alternaria ricini. [Descriptions of Fungi and Bacteria].

Author(s):  
M. B. Ellis

Abstract A description is provided for Alternaria ricini. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Ricinus communis. DISEASE: Seedling blight, leaf spot, inflorescence and pod rot of castor. Leaf lesions are irregular in outline, variable in size but often quite large, brown, zonate, with a yellow halo. Defoliation can be extensive. The inflorescence is attacked at any age and eventually develops a sooty appearance as sporulation occurs under high humidity conditions. The capsules can wilt suddenly and become purple dark brown, the seed is poorly filled and may become infected; normal dehiscence fails. Alternatively a sunken area appears on one side of the capsule and eventually covers the whole of it, the seed is fairly well grown and dehiscence is normal. Seedlings which are infected have stunted cotyledons, become spotted and may be killed. GEOGRAPHICAL DISTRIBUTION: Occurs in E. & W. Africa, S. Asia and S. & E. U.S.A., see CMI Map 345, ed. 2; one additional record is Angola. TRANSMISSION: Seed-borne. Infected capsules can give rise to seed which may have the coat, caruncle or endosperm infected. Seeds from such capsules give diseased seedlings. Seed dressings did not completely control the disease (39: 211).

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):  
J. Elizabeth

Abstract A description is provided for Colletotrichum graminicola. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Sorghum vulgare[Sorghum bicolor] and its varieties, S. halepensis, Zea, Triticum, Secale and other cultivated and wild genera distributed amongst at least 8 of the 12 tribes of Gramineae (Wilson 1914; Sprague, 1950). Also recorded on lucerne, red clover, soyabean and sweet clover (41: 368; 35: 300; 30: 598). DISEASES: Red stalk rot of internodal stem tissues, anthracnose and red leaf spot, also seedling blight of sorghum. On maize, cereals and other grasses the leaf spot form is most frequently seen, the spots are elliptical to elongated, usually 1-2 cm but occasionally confluent particularly on the midrib, pale orange to blackish purple, the centres greyish with age. Leaf anthracnose and stalk rots are characterized by the reddish discolouration, but pigmentation varies greatly according to host. Root rot is also recorded. GEOGRAPHICAL DISTRIBUTION: Africa (Ethiopia, Ghana, Guinea, Kenya, Libya, Malawi, Mauritius, Nigeria, Rhodesia, Sierra Leone, Sudan, Tanzania, Togoland, Uganda, Zambia); Asia (Burma, Hong Kong, India, Malaysia, Nepal, Pakistan); Australasia & Oceania (Australia, New Caledonia, New Hebrides, New Zealand), Europe (Finland, Germany, Great Britain, Rumania); North America (Canada, U.S.A.); Central America & West Indies (Cuba, Trinidad); South America (Argentina, Brazil, Chile, Guyana). TRANSMISSION: Seasonal persistence is on infected crop residues and weed hosts; sporulation has been observed on sorghum stalks and stubble after overwintering in the field (Le Beau et al., 1951). Also seed transmitted (35: 653).


Author(s):  
M. B. Ellis

Abstract A description is provided for Cochliobolus lunatus. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Recorded from a very wide range of angiosperms. DISEASE: Curvularia leaf spot, Curvularia seedling blight. GEOGRAPHICAL DISTRIBUTION: Widespread, especially in the tropics. TRANSMISSION: By infected seeds and air-borne conidia and ascospores. The fungus can survive in the soil in sclerotial form (47, 431).


Author(s):  
J. E. M. Mordue

Abstract A description is provided for Colletotrichum capsici. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Capsicum annuum, C. frutescens, Aristolochia, Cicer, cotton, Eggplant, jute, tomato, turmeric and many others from a wide range of families. DISEASE: Dieback, stem break, anthracnose, leaf spot, seedling blight, fruit rot (dieback of young fruits and ripe rot). GEOGRAPHICAL DISTRIBUTION: Tropics and subtropics of Africa, Asia, America and Australasia; has been recorded occasionally in Southern Europe. TRANSMISSION: Seed-borne; persists in decayed fruits and other plant debris from which conidia are dispersed locally by water and air currents. No extensive growth in soil reported.


Author(s):  
M. B. Ellis

Abstract A description is provided for Alternaria padwickii. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Oryza sativa. DISEASE: Stackburn, seedling blight and leaf spot of rice (Oryza sativa). Necrotic spotting on the roots and coleoptile leads to death of seedlings. Leaf spots are circular or oval, up to 1 cm diam., with a dark margin; the centre becomes pale and bears the black sclerotia. Spotting occurs on the glumes, the kernels are invaded and become discoloured and shrivelled. Sclerotia are formed in all infected areas (27: 447). GEOGRAPHICAL DISTRIBUTION: Widespread in S.E. Asia and parts of Oceania but not reported from Australia; it also occurs in Egypt, Malagasy Republic, Nigeria and Surinam (CMI Map 314, ed. 3, 1972). TRANSMISSION: By seed, up to 79% infection of seed samples has been found (25: 182). The pathogen probably survives between crops on the straw.


Author(s):  
A. Sivanesan

Abstract A description is provided for Curvularia penniseti. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Oryza, Pennisetum, Sorghum, Triticum. Also isolated from Allium, Dolichos and Richardia. DISEASE: Leaf spot of bajra or pearl millet (Pennisetum typhoides[Pennisetum glaucum]), seedling blight of Sorghum. GEOGRAPHICAL DISTRIBUTION: Australia, India, Indonesia, Malawi, Nepal, Nigeria, Pakistan, USA, Zimbabwe. TRANSMISSION: By wind-borne conidia and seed-borne (53, 3004; 59, 4574).


2021 ◽  
Vol 7 (7) ◽  
pp. 499
Author(s):  
Nitsan Birnbaum ◽  
Victoria Reingold ◽  
Sabina Matveev ◽  
Chandrasekhar Kottakota ◽  
Michael Davidovitz ◽  
...  

Growing global population and environmental concerns necessitate the transition from chemical to eco-friendly pest management. Entomopathogenic fungi (EPF) are rising candidates for this task due to their ease of growing, broad host range and unique disease process, allowing EPF to infect hosts directly through its cuticle. However, EPF’s requirement for high humidity negates their integration into conventional agriculture. To mitigate this problem, we formulated Metarhizium brunneum conidia in an oil-in-water Pickering emulsion. Conidia in aqueous and emulsion formulations were sprayed on Ricinus communis leaves, and Spodoptera littoralis larvae were introduced under low or high humidity. The following were examined: conidial dispersion on leaf, larval mortality, conidial acquisition by larvae, effects on larval growth and feeding, and dynamic of disease progression. Emulsion was found to disperse conidia more efficiently and caused two-fold more adhesion of conidia to host cuticle. Mortality from conidia in emulsion was significantly higher than other treatments reaching 86.5% under high humidity. Emulsion was also found to significantly reduce larval growth and feeding, while conferring faster fungal growth in-host. Results suggest that a Pickering emulsion is able to improve physical interactions between the conidia and their surroundings, while weakening the host through a plethora of mechanisms, increasing the chance of an acute infection.


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):  
T. V. Andrianova

Abstract A description is provided for Pestalozziella subsessilis, a colonizer of living leaves, causing leaf spot symptoms leading to leaves fading and dying. Some information on its dispersal and transmission, economic impacts, infraspecific variation and conservation status is given, along with details of its geographical distribution (USA (Florida, Kansas, Louisiana, Mississippi, Missouri, New Jersey, Wisconsin), Kazakhstan, Russia, New Zealand, Austria, Bulgaria, Czech Republic, Germany, Hungary, Italy, Poland, Ukraine, and United Kingdom), hosts (Geranium carolinianum (leaf), G. collinum (leaf), G. columbianum (leaf), G. columbinum (leaf), G. macrorrhizum (leaf), G. maculatum (leaf), G. palustre (leaf), G. pratense (leaf), G. pusillum (leaf), G. pyrenaicum (leaf), G. robertianum (leaf), G. sanguineum (leaf), G. sylvaticum (leaf), G. wlassovianum (leaf), Geranium sp., and Oxypolis rigidor [Tiedemannia rigida]) and associated fungi Chaetomella raphigera.


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.


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