Mycosphaerella fijiensis. [Descriptions of Fungi and Bacteria].

1974 ◽  
Author(s):  
J. L. Mulder
Keyword(s):  
Geographical Distribution ◽  
Leaf Surface ◽  
Early Stage ◽  
Lower Surface ◽  
Mycosphaerella Fijiensis ◽  
Lower Leaf Surface ◽  
The Pacific ◽  
Axis Parallel ◽  
Black Leaf Streak ◽  
Leaf Symptoms

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).

Haplobasidion musae. [Descriptions of Fungi and Bacteria].

1976 ◽  
Author(s):  
M. B. Ellis
Keyword(s):  
Geographical Distribution ◽  
Leaf Spot ◽  
Leaf Surface ◽  
Lower Surface ◽  
Axis Parallel

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.

Peronospora anemones. [Descriptions of Fungi and Bacteria].

1981 ◽  
Author(s):  
S. M. Francis
Keyword(s):  
New Zealand ◽  
Botrytis Cinerea ◽  
Downy Mildew ◽  
Geographical Distribution ◽  
Primary Infection ◽  
Leaf Surface ◽  
Plant Debris ◽  
Lower Leaf Surface ◽  
Glass Slides ◽  
Secondary Infections

Abstract A description is provided for Peronospora anemones. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Anemone coronaria, A. globosa. DISEASE: Downy mildew of anemones. Infected leaves lose their natural bloom, appearing dull green, almost grey in colour and are often down curled giving the plant a rounded appearance. As the disease progresses, leaf colour may change to shades of pink or purple with necrotic areas appearing on the older leaves. Invasion by secondary organisms (e.g. Botrytis cinerea) is common, especially after frost or storm injury, and this accelerates plant death. In favourable conditions conidiophores develop forming a whitish-grey down on the lower leaf surface, on the bracts and, less frequently, on the petioles. It is not uncommon for affected plants to show little or no sporulation and in these cases the presence of extensive intercellular mycelium and, later in the season, oospores in petioles and peduncles helps diagnosis. GEOGRAPHICAL DISTRIBUTION: Australasia (New Zealand); Europe (England, Jersey, France, Italy, Netherlands). TRANSMISSION: Primary infection is caused by oospores in plant debris in the soil. Tramier (1963) was unable to germinate oospores and thus work out precise details of the conditions affecting their germination but he showed evidence that regular and prolonged rain encouraged germination. Conidia, which cause secondary infections, are dispersed by rain and during harvesting of the flowers. Wind is thought to be unimportant in their dissemination as shown by glass slides covered with vaseline and placed near an infected crop (Tramier, 1965).

Drymonia betancurii (Gesneriaceae), a new species from northwestern Colombia

Phytotaxa ◽  
2015 ◽  
Vol 221 (1) ◽  
pp. 77 ◽  
Author(s):  
Laura Clavijo ◽  
John Littner Clark
Keyword(s):  
New Species ◽  
Leaf Surface ◽  
Lower Surface ◽  
Colombian Andes ◽  
White Spots ◽  
The Pacific ◽  
Dark Green ◽  
A New Species

A new species of Gesneriaceae from the Pacific slopes of the Colombian Andes is described and illustrated. The new species, Drymonia betancurii, is differentiated from other congeners by the following combination of characters: upper leaf surface with papillose-hispid trichomes, dark green and often covered with white spots; lower surface pitted; and corolla lobes orange-red with white to yellow margins.

Mycosphaerella henningsii. [Descriptions of Fungi and Bacteria].

1987 ◽  
Author(s):  
S. Little
Keyword(s):  
Geographical Distribution ◽  
Leaf Spot ◽  
Leaf Surface ◽  
Lower Leaf Surface ◽  
Leaf Spots ◽  
Brown Leaf Spot ◽  
Water Splash ◽  
Brown Leaf ◽  
Leaf Veins ◽  
Severe Infections

Abstract A description is provided for Mycosphaerella henningsii. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Manihot esculenta (cassava, manioc), M. glaziovii (manicoba, ceara rubber), M. palmata and, under laboratory conditions, Ipomoea sp. (36: 82). DISEASE: Brown leaf spot, sometimes referred to as leaf blight of cassava. At first the lesions start as small circular greenish yellow spots. These enlarge and become angular as they are delimited by the major leaf veins; on the upper leaf surface the spots are tan to light tan, 1-8 mm diam. with a dark brown slightly raised border. Minor leaf veins crossing the leaf spot are seen as black necrotic lines. In severe infections the leaf spots are surrounded by a yellow halo caused by a toxin produced by the advancing mycelium (Teri et al., 1977). On the lower leaf surface the spots are less distinct. Eventually the lesions may coalesce, and cause premature defoliation. GEOGRAPHICAL DISTRIBUTION: Generally found wherever cassava is cultivated (Teri, 1977). Africa: most countries; Asia: Jordan, Philippines, Sri Lanka, Thailand; North America: Dominican Republic, USA (Florida); South America: Bolivia, Brazil, Colombia, Peru, Venezuela. TRANSMISSION: Probably by wind-borne and water-splash dispersed conidia. During the dry season the fungus survives on the crop debris.

Peronospora manshurica. [Descriptions of Fungi and Bacteria].

1981 ◽  
Author(s):  
S. M. Francis
Keyword(s):  
Glycine Max ◽  
Leaf Area ◽  
Geographical Distribution ◽  
Seed Coat ◽  
Leaf Surface ◽  
Ryukyu Islands ◽  
Plant Debris ◽  
Lower Leaf Surface ◽  
Bright Yellow ◽  
Resting Spores

Abstract A description is provided for Peronospora manshurica. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: soyabean (Glycine max). DISEASE: Downy mildew of soyabean. Small discrete pale to bright yellow spots (2-8 mm diam.) are formed on the upper leaf surface. The size of the spots varies both with the severity of the attack and with the race of pathogen involved (33, 525). In a heavy infection the whole leaf area is affected and shrivels and dies. The conidiophores form a greyish-purple down on the lower leaf surface beneath these spots. Pods can become infected, without showing external symptoms, and the seeds invaded. Oospores develop on the seed surface and appear as a milky white crust consisting of a mass of the hyaline spherical resting spores. Plants developing from oospore encrusted seed may be systemically infected, remain small and stunted and die early. GEOGRAPHICAL DISTRIBUTION: CMI Map No. 268, ed. 3, 1979. Latvia (Serzane, 1962), Ryukyu Islands (Nuttonson, 1952) and Sweden (Gustavsson, 1959) should be added. TRANSMISSION: Usually by seed infected with oospores which form a crust on the seed coat or, very rarely, on the cotyledons. The pathogen can also be spread by oospores remaining on plant debris in the soil. Systemically infected plants develop and the conidia which form on their leaves initiate infection in the surrounding crop. Method of detecting oospores on soyabean seed are described by Pathak et al. (57, 5214). Their studies also indicate that oospores on the seed may remain viable foe to 8 years.

Fulvia fulva. [Descriptions of Fungi and Bacteria].

1976 ◽  
Author(s):  
P. Holliday
Keyword(s):  
Lycopersicon Esculentum ◽  
Leaf Area ◽  
Geographical Distribution ◽  
Leaf Surface ◽  
Lower Surface ◽  
Adverse Conditions ◽  
Major Disease ◽  
Fulvia Fulva ◽  
Severe Leaf ◽  
Olive Green

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.

scholarly journals Correlation between Epidermis Thickness, Leaf Trichome Length and Density with the Whitefly Bemisia tabaci Population on Five Local Soybean Cultivars

2019 ◽  
Vol 23 (1) ◽  
pp. 23
Author(s):  
Muhamad Lutfi ◽  
Purnama Hidayat ◽  
Nina Maryana
Keyword(s):  
Bemisia Tabaci ◽  
Leaf Surface ◽  
Lower Surface ◽  
Significant Loss ◽  
Epidermal Thickness ◽  
Lower Leaf Surface ◽  
Pests And Diseases ◽  
Soybean Cultivars ◽  
Randomized Design ◽  
Leaf Trichome

Soybeans compsumsion in Indonesia is about 2.7 million ton, while the national production is only about 0.7 million ton per year. There are some problems in the soybean production in Indonesia, including pests and diseases. Whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the important pests in soybeans causes a significant loss of yields. Developing soybean cultivars resistant to whitefly is one of method to reduce the production loss. This study aimed to determine the relationship between the physical characteristics of lower surface leaves and B. tabaci population on five local soybean cultivars. The experiments were conducted in the IPB greenhouse by Completely Randomized Design (RCD) using five soybean cultivars (Anjasmoro, Dena-1, Detam-3, Devon-1, and Wilis) with 3 replicates. Three plants of each cultivar were planted in a polybag, put under a cage, and after one week then infested with 5 female whiteflies. The parameters observed in this study were leaf epidermal thickness; density and length of trichome on lower leaf surface; and the number of egg, nymph, and adult of the whitefly. Observations were carried out every week, from 1−7 weeks after the plant was infested with the whitefly. The population of whitefly was affected by trichome density and length, as well as by the epidermal thickness of the lower leaf surface. The infestation of B. tabaci was higher in the soybean cultivars with denser and longer leaf trichomes, and thinner epidermal of the lower leaf surface. This result of this research suggests that it is necessary to include the characteristics of leaf trichome and epidermal thickness in the breeding program to produce soybean cultivars that are superior in productivity and resistant to whitefly.

Behavior of Neonate Imported Cabbageworm Larvae (Lepidoptera: Pieridae) Under Laboratory Conditions on Collard Leaves with Glossy or Normal Waxi

1997 ◽  
Vol 32 (3) ◽  
pp. 290-295 ◽  
Author(s):  
Kimberly A. Stoner
Keyword(s):  
Pieris Rapae ◽  
Leaf Surface ◽  
Lower Surface ◽  
Lower Leaf Surface ◽  
Laboratory Conditions ◽  
Leaf Surfaces ◽  
Observation Period

Movement and feeding of newly-hatched imported cabbageworms, Pieris rapae (L.), on the upper and lower leaf surfaces of collard plants with glossy and normal waxes were monitored using a videocamera. During the 50-min observation period, more of the larvae fed when placed on the lower surface of leaves with normal wax (50 to 68%) than on the upper surface (23 to 32%), or on either upper (27%) or lower (16%) surfaces of leaves with glossy wax. A larger portion of the larvae moved at least 1 mm on glossy leaves than on normal leaves, and they moved farther during the observation period on glossy than on normal leaves, and on the upper leaf surface compared to the lower leaf surface. The failure of a large proportion of the larvae to begin feeding on either surface of leaves with glossy wax is likely to be an important factor in the resistance to imported cabbageworms observed in the field.

Cercospora coffeicola. [Descriptions of Fungi and Bacteria].

1974 ◽  
Author(s):  
J. L. Mulder
Keyword(s):  
Geographical Distribution ◽  
Leaf Surface ◽  
Lower Surface ◽  
Cercospora Coffeicola ◽  
The Tropics ◽  
Brown Eye Spot

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.

Uromyces musae. [Descriptions of Fungi and Bacteria].

1971 ◽  
Author(s):  
J. L. Mulder
Keyword(s):  
Papua New Guinea ◽  
Geographical Distribution ◽  
Leaf Surface ◽  
New Guinea ◽  
The Philippines ◽  
Pacific Region ◽  
Lower Leaf Surface

Abstract A description is provided for Uromyces musae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On species of Musa. DISEASE: Rust of Musa spp. Forming rusty-brown to almost black, erumpent, somewhat linear pustules, mostly on the lower leaf surface. GEOGRAPHICAL DISTRIBUTION: Both banana rusts, Uromyces musae and Uredo musae, are restricted to parts of the S.W. Pacific region except for records of the former from the Congo and Nigeria. Both have been reported from the Philippines and Fiji. Uromyces musae also occurs in Wallis Island and Uredo musae in Malaysia (Sarawak), Papua New Guinea and Samoa. TRANSMISSION: No studies reported.

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