Septoria humuli. [Descriptions of Fungi and Bacteria].

Author(s):  
E. Punithalingam

Abstract A description is provided for Septoria humuli. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: Humulus lupulus (hop). DISEASE: Leaf spot of hop leading to premature defoliation. The disease has been reported initially to be confined to older and lower leaves and subsequently spreading to younger and upper leaves (Putto, Koul & Saraf, 1975). Female plants have been reported as being more susceptible than male plants. The visible symptoms are minute circular or irregular lesions, 1-3 mm wide and prominent on both surfaces of the leaves. With the progress of infection these lesions enlarge to form well defined spots, up to 6 mm wide, with ash white centres. Occasionally spots coalesce to form leaf blotches. Often severely infected leaves are killed and one report claims leaves on vines up to a height of 2-3 m have been affected (5, 1985). GEOGRAPHICAL DISTRIBUTION: Asia (India, Himachal Padesh, Kashmir); Europe (Czechoslovakia, Belgium, France, Germany, Hungary, USSR); North America (USA, Kansas, New Hampshire). TRANSMISSION: No specific studies reported. Presumably by conidia disseminated by water splash during hot weather.

Author(s):  
J. E. M. Mordue

Abstract A description is provided for Entyloma serotinum. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Symphytum spp., including S. asperrimum, S. bulbosum, S. cordatum, S. officinale, S. ottomanum and S. tuberosum; Borago officinalis; also recorded on Amsinckia, Lappula and Mertensia spp. (in USA) and Pulmonaria (in Europe, but see 64, 4163). DISEASE: Leaf spot of Symphylum, less frequently (though with similar symptoms) of other members of the Boraginaceae.GEOGRAPHICAL DISTRIBUTION: Africa: Algeria. Asia: Israel, USSR (Republic of Georgia). Australasia: New Zealand. Europe: widespread, including Austria, British Isles, Czechoslovakia, Denmark, France (including Corsica), Germany, Hungary, Italy, Netherlands, Poland, Portugal, Romania, Spain, Switzerland, USSR (Latvia), Yugoslavia. North America: USA. TRANSMISSION: Ustilospores survive on infected plant remains and in soil, and germinate to infect seedlings and the new seasons's leaves. In Europe conidia may also over-winter and initiate new infections in spring (Kaiser, 1936). During the growing season, conidia are disseminated by air currents and water-splash.


Author(s):  
E. Punithalingam

Abstract A description is provided for Septoria cucurbitacearum. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Cucumis melo, C. sativus, Cucurbita ficifolia (=C. melanosperma), C. maxima, C. moschata, C. pepo and Bryonia dioica (=B. cretica). DISEASE: Leaf spot of cantaloupe, cucumber, melon, pumpkin, squash and vegetable marrow. The visible symptoms are circular, olive brown lesions, prominent on the upper surface of the leaves. With the progress of the disease the spots enlarge, usually reaching 3-5 mm diam., occasionally 8 mm wide and soon dry up. Older lesions tend to turn white revealing several pycnidia embedded within the tissue. GEOGRAPHICAL DISTRIBUTION: Africa (Ethiopia, Kenya, Zambia); Australasia & Oceania (Australia); Europe (Bulgaria, Denmark, France, Germany, Hungary, Italy, Portugal, Rumania, USSR); North America (USA, Delaware, Massachusetts, New Hampshire, New York, Pennsylvania, Wisconsin). TRANSMISSION: Presumably by conidia disseminated by water splash in wet weather or heavy dews.


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.


Author(s):  
E. Punithalingam

Abstract A description is provided for Septoria carthami. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Carthamus tinctorius and C. mareoticus. DISEASE: White leaf spot of safflower. Early symptoms appear as small distinct brownish lesions which enlarge and become circular or irregular and up to 6 mm wide. As the disease progresses lesions sometimes coalesce to form large blotches. Older lesions are usually bordered by dark brick margins with ash grey centres. GEOGRAPHICAL DISTRIBUTION: Africa (Egypt); Asia (Iraq, Turkey, USSR, West Siberia); Europe (Bulgaria, Rumania); North America (USA, Indiana, Texas). TRANSMISSION: It has been claimed that the fungus was introduced into West Siberia with infected seeds (14, 493-494). Also the fungus is probably disseminated by water-splash or by mechanical means.


Author(s):  
E. Punithalingam

Abstract A description is provided for Gnomonia comari. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Fragaria vesca, F. chilonensis var. ananassa and Fragaria cvs. Also on Agrimonia, Alchemilla, Comarum, Epilobium, Geum, Potentilla and Sanguisorba. DISEASE: Leaf blotch, dry necrosis of sepal tips, fruit rot and dying of strawberry plants. Also rotting of strawberry runners in cold storage (50, 189). Although the disease is economically unimportant in Switzerland, Bolay (1972) claims in Germany, UK and North America yield losses can reach 70%. GEOGRAPHICAL DISTRIBUTION: Africa (Zimbabwe); Asia (Israel); Australasia & Oceania (New Zealand); Europe (Denmark, Finland, France, Germany, Greece, Netherlands, Poland, Rumania, Spain, Sweden, Switzerland, UK, Yugoslavia); North America (Canada, British Columbia, Newfoundland, Nova Scotia, Ontario, Quebec; USA, California, Maine, Michigan, New Hampshire). TRANSMISSION: By conidia and ascospores disseminated by water splash during humid conditions (Bolton, 1954). The fungus overwinters on leaves left in the field and in nature perithecia occur on overwintered leaves in early spring. Infection starts early in the season (Bolton, 1954; 51, 2693) by the entry of the fungus through stomata and wounds (33, 737; Bolay, 1972). Once the fungus has entered the leaf it penetrates the parenchyma cells and progessses towards the vascular bundles and enters the vessels producing profuse mycelium and subsequently numerous pycnidia (Bolton, 1954). In Western Spain under laboratory conditions pycnidia have been produced on infected plants in 4-5 days and perithecia in 8-10 days (52, 3776). In Canada pycnidia were observed in the cortex of petioles 4 weeks after inoculation and leaves with pycnidia kept in a moist chamber were found to develop perithecia in 4-6 days (Bolton, 1954). Perithecia developed in this way took 10-12 days to mature.


Author(s):  
E. Punithalingam

Abstract A description is provided for Mycosphaerella convallariae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: Convallaria majalis (lily of the valley). DISEASE: Leaf spot or blotch or blight of lily of the valley. The first disease symptoms appear a few days after rain or a wet period (McKeen & Zimmer, 1964). At first the visible symptoms are minute necrotic spots with halos which later enlarge rapidly to form oblong to circular spots or blotches with concentric layers of light and dark zones. When the infection is severe secondary lesions develop, coalesce and kill the leaf. GEOGRAPHICAL DISTRIBUTION: Europe (Austria, Hungary, Italy, Romania, U.S.S.R.); Eastern North America (Canada, Ontario; U.S.A., Pennsylvania). TRANSMISSION: Conidia are dispersed by water splash. In Ontario, Canada, the fungus is reported to overwinter in the ascomatal state and ascospores are released following a wet period in May or June (McKeen & Zimmer, 1964). It has also been suggested that two to four cycles of the Ascochyta stage are completed in the summer.


Author(s):  
S. Little

Abstract A description is provided for Cercospora circumscissa. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Prunus amygdalus, P. avium, P. cerasus, P. domestica, P. persica, P. spinosa. DISEASE: Leaf spot or 'shot hole' of stone fruit trees. The disease first appears early in the season on the younger leaves as yellowish spots with dark centres. The margin of the spots then becomes thickened and dark or reddish-brown, while the centre becomes grey, dries, shrinks and ultimately falls out. Eventually most of the leaves on the tree become riddled with holes. Shallow circular leaf spots may also form on the branches and the fruit (McAlpine, 1902). GEOGRAPHICAL DISTRIBUTION: Africa: Morocco, Zimbabwe; Asia: Cyprus, India, Iran, Israel, Japan, Palestine, Australasia: Australia (Queensland), Europe: Britain, France, Germany, Italy, Romania Turkey, USSR (Russia), Yugoslavia; North America: USA (Alabama, California, Florida); South America: Argentina. TRANSMISSION: By wind-borne and water splash-dispersed conidia (McAlpine, 1902). The fungus survives adverse conditions in the fallen foliage as stromatic cells or as the teleomorph.


Author(s):  
A. Sivanesan

Abstract A description is provided for Pyrenophora erythrospila. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Agrostis, Hordeum and Triticum. DISEASE: Leaf spot of bent grass and red top. GEOGRAPHICAL DISTRIBUTION: Australia, Europe, New Zealand, North America. TRANSMISSION: By wind-borne conidia.


Author(s):  
P. F. Cannon

Abstract A description is provided for Isthmiella faullii. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Apparently confined to Abies balsamea. DISEASE: Causes a needle blight of Abies balsamea. According to Darker (1932), it 'is the commonest and most destructive of the Hypodermataceae on Abies balsamea in eastern North America'. It is particularly damaging to seedlings and juvenile plants. In northern Ontario, from where the disease was originally identified, infection occurs during the summer, but signs of the disease do not appear until the following spring, when needles become brown and conidiomata develop, conidia being discharged in July, and shortly after this ascomata begin to form, maturing in July of the following year. GEOGRAPHICAL DISTRIBUTION: Reported from Canada: Nova Scotia, Ontario, Quebec and USA: Michigan and New Hampshire. TRANSMISSION: Through air dispersal of ascospores, which directly infect the leaves (Darker, 1932).


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.


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