Septoria apiicola. [Descriptions of Fungi and Bacteria].

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):  
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):  
D. J. Stamps

Abstract A description is provided for Phytophthora infestans. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Potato, tomato, other Solanaceae. DISEASE: Late blight of potato and tomato. GEOGRAPHICAL DISTRIBUTION: World-wide (CMI Map 109, ed. 5, 1982). Distribution of compatibility types differs; the A1 and A2 are both present in Mexico (37, 503), whereas elsewhere only the A1 was thought to occur until the A2 was recorded in Switzerland in 1981 (64, 288). TRANSMISSION: Sporangia are readily detached and disseminated by wind and rain splash. Infection may spread from early potato crops to nearby maincrops. Tubers are contaminated by sporangia washed into the soil from blighted haulms (60, 2899), or on exposure at lifting. The fungus overwinters in tubers. Seed tubers, tuber refuse from clamp sites and volunteer plants provide sources of new infection (52, 216; 56, 973). Tomatoes were infected from potato crops (51, 3560).


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):  
Chi-yu Chen

Abstract A description is provided for Leptosphaeria cylindrospora. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Although the fungus appears on dry stems of its host, it is not known to cause any pathological symptoms. HOSTS: Epilobium (Onagraceae). GEOGRAPHICAL DISTRIBUTION: NORTH AMERICA: Canada (Manitoba), USA (Alaska, Arkansas, Colorado, Idaho, Washington). ASIA: Kazakhstan (VASYAGINA et al., 1987). EUROPE: Czech Republic, Germany, Hungary, Romania (BONTEA, 1955), Sweden, Switzerland. TRANSMISSION: Ascospores are dispersed by wind and rain-splash; the fungus presumably overwinters on dead host tissue and the ascospores are dispersed in the next favourable season.


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):  
Chi-yu Chen

Abstract A description is provided for Leptosphaeria purpurea. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Although the fungus appears on dry stems of its hosts, which are mainly herbaceous, it is not known to cause any pathological symptoms. HOSTS: Artemisia, Betonica, Carduus, Cirsium, Cnicus, Clinopodium, Helianthus, Satureja and Senecio. GEOGRAPHICAL DISTRIBUTION: NORTH AMERICA: Canada (Quebec, Ontario), USA (New York). ASIA: Pakistan. EUROPE: Austria, Belgium, Czech Republic, Germany, Great Britain, Hungary, Slovak Republic, Sweden. TRANSMISSION: Conidia and ascospores are dispersed by wind and rain-splash; the fungus presumably overwinters on dead host tissue and the ascospores are dispersed in the next favourable season.


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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