Cercospora coffeicola. [Descriptions of Fungi and Bacteria].

Author(s):  
J. L. Mulder

Abstract A description is provided for Cercospora coffeicola. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Coffea spp. DISEASE: Brown eye spot of coffee; symptoms occur on leaves and berries. On the former the small chlorotic spots expand, becoming deep brown but lighter in colour on the lower surface; the centre becomes grey white and surrounded by a ring of dark brown tissue, 5-15 mm diam., sometimes with a yellowish halo. This is most distinct on the upper leaf surface; the dark sporulation is seen in the greyish area. Leaves may be shed. On green berries lesions are brown, sunken, irregular or oval with ashy centres, rarely > 5 mm long and sometimes with a purplish surround. Infection may penetrate the berry thus causing the pulp to stick to the bean during fermentation. GEOGRAPHICAL DISTRIBUTION: Throughout the tropics (CMI Map 59, ed. 4, 1973). TRANSMISSION: Conidia probably windborne mostly during the day. The possible role of any other hosts seems unimportant.

Author(s):  
M. B. Ellis

Abstract A description is provided for Cordana musae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Musa sapientum. DISEASE: Leaf blotch or spot of banana (Musa). Small brown spots enlarge to an oval or sometimes a diamond shape, a darker red-brown margin and zonation becomes quite marked with age. A chlorotic halo is conspicuous, especially on the lower surface. Necrotic tissue may occur as strips from edge to midrib, and a marginal necrosis with an uneven, zigzag, chlorotic edge separating healthy from diseased tissue may develop. GEOGRAPHIC DISTRIBUTION: Widespread in the tropics with host (CMI Map 168, ed. 3, 1971). Additional records not mapped are: Cape Verde Islands, Cuba, US Trust Territory. TRANSMISSION: Air-dispersed; a diurnal periodicity with a peak near 0700 hr was found in Jamaica (42: 37) and spore discharge has been described in detail (41: 666).


Author(s):  
P. Holliday

Abstract A description is provided for Fulvia fulva. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Lycopersicon esculentum. DISEASE. Leaf mould of tomato is a major disease of this crop. The first symptoms are pale chlorotic spots (margins indefinite) on the upper leaf surface. Sporulation, on the lower surface beneath the spots, is downy, light grey, becoming buff to tawny brown or olive green. Defoliation may occur. Infection of blossoms and fruits is much less important. There was an interval of c. 6 weeks between the incidence of severe leaf colonization (50% leaf area) and decreases in yield (48, 1982). GEOGRAPHICAL DISTRIBUTION: Worldwide (CMI Map 77, ed. 5, 1972). TRANSMISSION: By air-dispersed conidia; these were considered to be viable for 9-12 months under adverse conditions (18, 142). Seed contamination may occur.


Author(s):  
J. L. Mulder

Abstract A description is provided for Mycosphaerella fijiensis. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Musa spp. DISEASE: Black leaf streak of banana. A comparison of the conidial states of M. fijiensis and M. musicola (CMI Descript. 414, Sigatoka of banana) has been given, as has a detailed account of the symptoms (48, 3071; and see 44, 191, 1180; 45, 1867). Initially reddish-brown specks form on the lower leaf surface, they elongate to become streaks up to 20 × 2 mm, with the long axis parallel to the leaf veins and at this stage are more clearly visible on the lower leaf surface. The streaks can be extremely numerous; they darken, become almost black and are clearly seen on the lower surface. The streak develops into a fusiform or elliptical spot, with a light brown, water soaked margin and a dark centre. The centre dries out becoming light grey or buff, sunken, surrounded by a narrow dark brown or black border and often by a chlorotic zone beyond. Necrosis of the whole leaf can occur in 3-4 weeks. Some differences in the macroscopic leaf symptoms between black leaf streak and Sigatoka occur. In the latter disease the early stage streaks are clearly seen on the upper surface and are yellowish; in the former the streaks are darker at similar stages in development. But there are no clear macroscopic differences between the mature spots of the two diseases. GEOGRAPHICAL DISTRIBUTION: The disease was first described from Fiji in 1963 (although because of probable confusion with M. musicola there may be earlier unsubstantiated records). It is widespread in the islands of the Pacific (Oceania); it may be absent from the mainland of S.E. Asia and does not occur in Australia, Africa or America (CMI Map 500, ed. 1, 1974). TRANSMISSION: Perithecia are formed in abundance and, therefore, the ascospores are considered important in spread, perhaps more so than the conidia (44, 1180; 45, 1867). In dry weather ascospore concentration reached a max. near 0600 h as dew formed. On rainy days peak concentrations were reached shortly after rain began. Seasonal increases in ascospores were associated with those of rainfall and relative humidity (52, 4160).


Author(s):  
M. B. Ellis

Abstract A description is provided for Haplobasidion musae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On living leaves of Musa causing diamond-shaped, white, pale grey or brown spots each with dark purple to black border, spots often very pale on the upper surface, darker on the lower surface. DISEASE: Diamond (or Malayan) leaf spot of banana (Musa). Although the fungus was described only in 1957 the disease, as has been pointed out (51, 1688), was first reported by Knowles from Fiji in 1916. On the upper leaf surface the spots are greyish white with straight edges, diamond shaped with a black border, 4-5.5 × 3-4 mm, longer axis parallel to the veins, border 0.5 mm wide. These lesions may be surrounded by a watersoaked area often several times their size. GEOGRAPHICAL DISTRIBUTION: Fiji, Malaysia (W.) and Samoa (W.); (CMI Map 474, ed. 1, 1971). TRANSMISSION: No studies reported.


2012 ◽  
Vol 279 (1742) ◽  
pp. 3520-3526 ◽  
Author(s):  
Brian Tilston Smith ◽  
Amei Amei ◽  
John Klicka

Climatic and geological changes across time are presumed to have shaped the rich biodiversity of tropical regions. However, the impact climatic drying and subsequent tropical rainforest contraction had on speciation has been controversial because of inconsistent palaeoecological and genetic data. Despite the strong interest in examining the role of climatic change on speciation in the Neotropics there has been few comparative studies, particularly, those that include non-rainforest taxa. We used bird species that inhabit humid or dry habitats that dispersed across the Panamanian Isthmus to characterize temporal and spatial patterns of speciation across this barrier. Here, we show that these two assemblages of birds exhibit temporally different speciation time patterns that supports multiple cycles of speciation. Evidence for these cycles is further corroborated by the finding that both assemblages consist of ‘young’ and ‘old’ species, despite dry habitat species pairs being geographically more distant than pairs of humid habitat species. The matrix of humid and dry habitats in the tropics not only allows for the maintenance of high species richness, but additionally this study suggests that these environments may have promoted speciation. We conclude that differentially expanding and contracting distributions of dry and humid habitats was probably an important contributor to speciation in the tropics.


2021 ◽  
Author(s):  
Santiago Valencia ◽  
Juan F. Salazar ◽  
Juan Camilo Villegas ◽  
Natalia Hoyos ◽  
Mateo Duque-Villegas
Keyword(s):  

Author(s):  
V. P. Heluta

Abstract A description is provided for Arthrocladiella mougeotii. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Powdery mildew of Lycium species only. The mycelium, conidiophores, conidia and ascomata form first white, then dirty-grey patches on damaged green parts of the host. Infected parts are deformed slightly and, in cases of high infection, plants can lose their ornamental qualities. Damaged leaves can fall prematurely. HOSTS: Lycium barbarum (= L. europaeum), L. chinense, L. dasystemum, L. halimifolium, L. ovatum, L. potaninii, L. rhombifolium, L. ruthenicum. [Type host - Lycium barbarum] GEOGRAPHICAL DISTRIBUTION: Africa: Canary Islands. Asia (temperate areas only): Armenia, Azerbaijan, China, Republic of Georgia, Israel, Japan, Kazakhstan, Kirghizistan, Korea, Russia (Russian far east), Tadzhikistan, Taiwan, Turkey, Turkmenistan, Uzbekistan. Australasia: New Zealand (introduced). Europe: Austria, Belgium, Bulgaria, Czech Republic, Estonia, France, Germany, Hungary, Italy, Netherlands, Norway, Poland, Rumania, Slovakia, Sweden, Switzerland, UK, Ukraine (southern), former Yugoslavia. North America: USA (introduced). TRANSMISSION: By wind-dispersed conidia. The rôle of ascospores in disease transmission is unknown, although it has been supposed that they can cause the initial stage of the disease.


Author(s):  
J. N. Kapoor

Abstract A description is provided for Podosphaera leucotricha. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Malus spp., chiefly on M. pumila (apple), peach (Prunus persica), quince (Cydonia ualgaris) and Photinia spp. also attacked (Hirata, 1966). Also reported on almond fruit (43, 2544). DISEASE: Powdery mildew of apple. GEOGRAPHICAL DISTRIBUTION: Africa (? Kenya, Rhodaia, South Africa, Tanzania); Asia (China, India, Israel, Japan, U.S.S.R.); Australia and New Zealand, Europe (widely distributed) North America (Canada and U.S.A.); South America (Argentina, Brazil, Chile, Colombia, Peru). (CMI map 118). TRANSMISSION: Overwinters on host as dormant mycdium in blossom buds. The role of deistothecia in overwintering is doubtful. Spread by wind-borne conidia (Anderson, 1956).


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):  
C. Booth

Abstract A description is provided for Gibberella zeae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Wheat, maize, barley, carnations and other ornamentals; also reported infecting Lycopersicon, Pisum, Trifolium and Solanum DISEASE: Seedling blight, pre-emergence and post-emergence blight, root and foot rot, brown rot, culm decay, head or kernel blight (scab or ear scab) of wheat, maize, barley and other cereals. Leaf and flower rot of carnations and other ornamentals. Also reported infecting species of Lycopersicon, Pisum, Trifolium and Solanum. GEOGRAPHICAL DISTRIBUTION: Worldwide on maize and rice in the tropics. Wheat, oats, barley and rye in temperate regions. TRANSMISSION: By planting infected or infested seeds or by planting in infested soil. Secondary infection occurs widely by water droplets under moist conditions or by ascospore discharge.


Sign in / Sign up

Export Citation Format

Share Document