Septoria lycopersici. [Descriptions of Fungi and Bacteria].

Author(s):  
B. C. Sutton

Abstract A description is provided for Septoria lycopersici. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Lycopersicon esculentum. Also on Datura stramonium, Solanum carolinense, S. nigrum and S. melongena. Other species of Lycopersicon and Solanum tuberosum have been reported susceptible on inoculation (MacNeill, 1950). DISEASE: Leaf spot of tomato. Lesions abundant, amphigenous, circular to irregular, rarely confluent, often vein-limited and depressed, water-soaked, becoming pale brown and later grey with dark margins, up to 2 mm. diam. All stages of growth of the plant may be attacked. Severe infection causes leaves to shrivel and produces premature defoliation, exposing the fruit to sun-scald. GEOGRAPHICAL DISTRIBUTION: World-wide on tomato (CMI Map 108, ed. 3, 1959). TRANSMISSION: Spores are disseminated by rain-splash and wind-blown water, and may also be carried on the hands and clothing of fruit-pickers or by insects (chiefly beetles) (Martin, 1918; 20: 183). The fungus is not a soil inhabitant but may persist in a viable condition from one season to the next on debris of diseased plants incorporated in the soil (3: 615; 20: 181). Solanaceous weeds also serve as one of the main means of overwintering the pathogen (3: 615). Seed contaminated with spores can produce infected seedlings (20: 183) but there is some doubt whether the pathogen is truly seed-borne (32: 154; 43, 3324; Noble et al, 1958).

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):  
E. Punithalingam

Abstract A description is provided for Septoria socia. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Chrysanthemum leucanthemum[Leucanthemum vulgare] and by inoculation on Chrysanthemum morifolium, C. maximum, C. parthenium, C. segetum and Achillea ptarmica (Punithalingam & Wheeler, 1965). DISEASE: Leaf spot of ox-eye daisy, C. leucanthemum. Lesions few, conspicuous on the upper side, rarely confluent, necrotic areas, becoming chocolate brown and later darker or even black, with a reddish purple border, 5 mm across. Lesions are confined to the lower leaves of the plant. Severe infection involving the entire leaf surface during moist conditions causes premature death. GEOGRAPHICAL DISTRIBUTION: Czechoslovakia, Great Britain, Italy, Spain, Pakistan and U.S.S.R. (Literature, Herb. IMI). TRANSMISSION: Not known. It is possible that, like other Septoria spp. on Chrysanthemum this species may be disseminated by rain-splash and by contact.


Author(s):  
J. F. Bradbury

Abstract A description is provided for Erwinia mallotivora. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: Mallotus japonicus (Euphorbiaceae). DISEASE: Bacterial leaf spot. The disease starts as water-soaked spots on the newly developing leaves in May and June. The spots tend to form close to the main veins. They enlarge and become angular as they are restricted by the veins, becoming dark brown, and often with a chlorotic halo about 1 mm wide. Spots may coalesce and kill the leaf, and shoot blight may also occur. Under humid conditions bacteria may exude on to the leaf surface. GEOGRAPHICAL DISTRIBUTION: Japan. TRANSMISSION: Unknown, but presumably rain splash plays a part at least in secondary spread.


Author(s):  
G. S. Saddler

Abstract A description is provided for Xanthomonas fragariae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Fragaria × ananassa (Rosaceae); by artificial inoculation: Fragaria virginiana, F. vesca, Potentilla fruticosa and P. glandulosa (Rosaceae). DISEASE: Angular leaf spot and vascular decline or collapse of strawberry. First described in 1962 in North America. The leaf spot phase appears as minute water-soaked spots on the underside of leaves surrounded by the smallest veins. In the early stages symptoms are only visible on the leaf underside. Spots enlarge, coalesce, penetrate to the upper leaf surface and darken, turning into large, irregular necrotic areas. They have a shiny appearance and are usually covered by bacterial exudate which, when dry, turns brown and appears as gum-like scales. Spots coalesce more frequently along the primary and secondary veins. The dead tissues tear and break off, and the diseased leaf may assume a ragged appearance. Heavy losses may occur with frequent overhead sprinkler irrigation. The conditions favouring infection are moderate to cool daytime temperatures (about 20°C), low night-time temperatures and high humidities (MAAS, 1998). In addition, blossom blight of strawberry has been found in California and is caused by a complex of X. fragariae and Cladosporium cladosporioides (GUBLER et al., 1999). GEOGRAPHICAL DISTRIBUTION: AFRICA: Ethiopia, Réunion. NORTH AMERICA: Canada (New Brunswick, Newfoundland, Nova Scotia, Ontario, Quebec), USA (California, Florida, Kentucky, Minnesota, North Carolina, Wisconsin). SOUTH AMERICA: Argentina, Brazil (Minas Gerais, Rio Grande do Sul, Sao Paulo), Chile, Ecuador, Paraguay, Uruguay, Venezuela. ASIA: Taiwan, Israel. AUSTRALASIA: Australia (New South Wales, South Australia, Victoria), New Zealand. EUROPE: Belgium, France, Germany, Greece, Italy (Sicily), Netherlands, Portugal, Romania, Spain, Switzerland, Ukraine. TRANSMISSION: Rain splash from infested leaf litter in the soil on to young healthy leaves. Penetration occurs through the stomata. Infections of the crowns occur through local wounds or downwards from affected leaves. Bacteria can overwinter in leaf litter and for many years in dried leaf material. Residues of infected leaves and crown infections on runners used for planting are sources of inoculum for primary infections.


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):  
E. Punithalingam

Abstract A description is provided for Septoria cannabis. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: Cannabis sativa (hemp). DISEASE: White leaf spot or leaf blight of hemp. Symptoms usually appear on basal leaves as round or ellipsoidal to polygonal, whitish or ochraceous yellow lesions with a conspicuous dark brown border. Affected leaves become curled and withered up towards the edges and fall prematurely leaving much of the lower part of the stem defoliated (15, 97, 805). GEOGRAPHICAL DISTRIBUTION: Asia, Europe and North America (CMI Map No. 477, ed. 1, 1971). New records not mapped are: Asia (Kashmir, Pakistan). TRANSMISSION: Detailed studies have not been reported but conidia are presumed to be disseminated by rain-splash and wind blown water. The fungus could also be carried over in crop residues.


Author(s):  
J. F. Bradbury

Abstract A description is provided for Pseudomonas lachrymans. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Cucumis sativus and C. anguria. It may also attack C. melo var. inodorus (26: 140) and some other cucurbits. Elliott (31: 105) lists 10 hosts, all in the Cucurbitaceae. DISEASE: Angular leaf spot of cucumber. Small water-soaked spots appear on the leaves, petioles, stems, and fruits. On leaves they enlarge and become angular as they are delimited by veins They become tan to brown and the necrotic centres may fall out. On petioles, stems, and fruit spots develop white crusty bactenal exudate. A fruit rot develops if the bacteria penetrate deeply. GEOGRAPHICAL DISTRIBUTION: North and parts of Central America, most of Europe, U.S.S.R., China, Japan, W. Australia, Israel, southern Africa. (CMI Map 355, ed. 2, 1964). TRANSMISSION: The pathogen is seed-borne and infects the cotyledons dunng germination. It can overwinter on infected crop residue in the soil and has been found viable in dry leaf matenal after two and a half years (36: 677). The bacteria are carried from plant to plant within a crop by rain splash and probably by insects (Carsner, 1918; 31: 272). Workers can also spread the disease, particularly when foliage is wet with rain or dew (35: 810).


Author(s):  
G. S. Saddler

Abstract A description is provided for Burkholderia cepacia. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Common host is Allium cepa, but can also cause disease in Allium sativum. Also identified as causing disease in Lycopersicon esculentum (63, 3168), a cavity disease of a cultivated mushroom (Agaricus bitorquis) (72, 5605) and a leaf spot on the a number of orchids including Cymbidium spp., Dendrobium sp. and Paphiopedilum spp. (66, 4326). The bacterium can also be found in soil, in clinical material, in disinfectant solutions and as an opportunistic pathogen of man and animals. It is gaining in significance as a major pathogen for sufferers of cystic fibrosis (Isles et al., 1984; McKevitt & Woods, 1984; Thomassen et al., 1985). DISEASE: Onion slippery skin; this is a rot of bulb scales, usually occurring at or near maturity, sometimes in storage. The bacterium does not appear to be strongly invasive, attacking plants that are damaged or weakened. Bacteria are thought to gain entry through the neck or leaf blades as the foliage falls over and the epidermis breaks, at maturity (64, 5550). GEOGRAPHICAL DISTRIBUTION: Worldwide. TRANSMISSION: Appears to be a soilborne wound pathogen.


Author(s):  
G. F. Laundon

Abstract A description is provided for Uromyces appendiculatus. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Dolichos, Phaseolus and Vigna species. DISEASE: Rust on leaves of French, Lima, and Scarlet Runner beans, and other Phaseolus spp., and cowpeas. The reddish-brown, circular sori may be surrounded by a yellow halo in some varieties. Complete defoliation and total loss of crop results in seasons favouring severe infection. GEOGRAPHICAL DISTRIBUTION: World-wide wherever beans are grown (CMI Map 290, Ed. 2, 1964). TRANSMISSION: By urediospores disseminated by wind, and through contact with animals including man and his implements. Indirect evidence of the possibility of introduction into Sierra Leone on seed imported from Ghana and S. Africa has been given by Deighton (25: 253). Some 40% of urediospores stored for 2 yr. at -60°C, and 16% stored more than 600 days at -18°C, have survived with virulence unimpaired, and it is thought that the rust is thus able to overwinter on bean trash and trellis poles in the United States (42: 167; 43, 299).


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).


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