The infection of soybean leaves by Phakopsora pachyrhizi during conditions of discontinuous wetness.

The ability of Phakopsora pachyrhizi to cause infection under conditions of discontinuous wetness was investigated. In in vitro experiments, droplets of a uredospore suspension were deposited onto the surface of polystyrene. After an initial wetting period of either 1, 2 or 4 h, the drops were dried for different time intervals and then the wetness was restored for 11, 10 or 8 h. Germination and appressorium formation were evaluated. In in vivo experiments, soybean plants were inoculated with a uredospore suspension. Leaf wetness was interrupted for 1, 3 or 6 h after initial wetting periods of 1, 2 or 4 h. Then, the wetting was re-established for 11, 10 or 8 h, respectively. Rust severity was evaluated 14 days after inoculation. The germination of the spores and the formation of the appressoria on the soybean leaves after different periods of wetness were also quantified in vivo by scanning electron microscopy. P. pachyrhizi showed a high infective capacity during short periods of time. An interruption of wetness after 1 h caused average reductions in germination from 56 to 75% and in appressorium formation from 84 to 96%. Rust severity was lower in all of the in vivo treatments with discontinuous wetness when compared to the control plants. Rust severity was zero when the interruption of wetness occurred 4 h after the initial wetting. Wetting interruptions after 1 and 2 h reduced the average rust severity by 83 and 77%, respectively. The germination of the uredospores on the soybean leaves occurred after 2 h of wetness, with a maximum germination appearing after 4 h of wetness. Wetness interruption affected mainly the spores that had initiated the germination

Detection of Xylella fastidiosa in coffee germplasm

A bactéria Xylella fastidiosa possui uma ampla gama de plantas hospedeiras que inclui espécies de pelo menos 28 famílias de mono e dicotiledôneas. Em cafeeiro (Coffea spp.), a ocorrência dessa bactéria foi relatada previamente em cultivares da espécie Coffea arabica. Estudos foram realizados para determinar a presença de X. fastidiosa em diferentes espécies e híbridos interespecíficos de cafeeiro. As amostragens foram realizadas em dois anos consecutivos. As espécies de cafeeiro examinadas foram: C. kapakata, C. canephora, C. racemosa, C. arabica, C. dewevrei, C. stenophylla e C. eugenioides. Também foram incluídos neste estudo híbridos interespecíficos de C. arabica: C. arabica x C. dewevrei, C. arabica x C. eugenioides, C. arabica x C. racemosa e C. arabica x C. robusta. Foram coletadas amostras de ramos plagiotrópicos de diferentes plantas para cada espécie e híbrido. A detecção de X. fastidiosa nas amostras foi realizada utilizando os testes serológicos de DAS-ELISA e imunofluorescência indireta. A bactéria foi detectada nas sete espécies e nos quatro híbridos de cafeeiro examinados. Entretanto, as plantas aparentemente não apresentavam sintomas de infecção por X. fastidiosa. A espécie C. arabica apresentou a maior proporção de amostras positivas e maiores valores de absorbância no teste de DAS-ELISA. Em contraste, as espécies C. racemosa e C. dewevrei foram as que apresentaram menores proporções de amostras positivas para presença de X. fastidiosa, como também menores valores de absorbância no teste de DAS-ELISA.The bacterium Xylella fastidiosa has a large host range, including species of 28 different mono and dicotiledoneous plant families. On coffee (Coffea spp.), X. fastidiosa was previously reported only on the species Coffea arabica. Studies were carried out to determine the presence of X. fastidiosa in different species and interspecific hybrids of coffee. The species of coffee included in this study were the following: C. kapakata, C. canephora, C. racemosa, C. arabica, C. dewevrei, C. stenophylla and C. eugenioides. The interespecific hybrids of C. arabica examined were the following: C. arabica x C. dewevrei, C. arabica x C. eugenioides, C. arabica x C. racemosa and C. arabica x C. robusta. Samples were collected from plagiotropic branches of different plants for each species or hybrid. Four replicates were examined for each coffee accession examined. Detection of X. fastidiosa in the samples was determined by DAS-ELISA and indirect immunofluorescence. The bacterium was detected in all seven species and four hybrids of coffee studied. However, the plants did not show any symptom of infection by X. fastidiosa. The species C. arabica showed the highest proportion of positive samples and the largest absorbance values in the DAS-ELISA test. In contrast, the species C. racemosa and C. dewevrei showed the lowest proportion of positive samples for the presence of X. fastidiosa, as well as, the lowest absorbance values in the DAS-ELISA test

Abundance and Species Richness of Leafhoppers and Planthoppers (Hemiptera: Cicadellidae and Delphacidae) in Brazilian Maize Crops

Fil: De Oliveira, Charles Martins. Embrapa Cerrados. Planaltina. Brasília/DF; BrazilFil: De Oliveira, Elizabeth. Embrapa Milho e Sorgo. Sete Lagoas/MG; BrazilFil: Prazeres De Souza, Isabel Regina. Embrapa Milho e Sorgo. Sete Lagoas/MG; BrazilFil: Alves, Elcio. DuPont do Brazil S.A. DivisÆo Pioneer Sementes. Itumbiara/GO; BrazilFil: Dolezal, William. Pioneer Hi-Bred International. Itumbiara/GO; BrazilFil: Paradell, Susana Liria. División Entomología. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Marino de Remes Lenicov, Ana María. División Entomología. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Frizzas, Marina Regina. Universidade de Brasília. Departamento de Zoologia. Instituto de Ciências Biológicas. Brasília/DF; Brazi

Fungal planet description sheets: 951–1041

Novel species of fungi described in this study include those from various countries as follows: Antarctica , Apenidiella antarctica from permafrost, Cladosporium fildesense fromanunidentifiedmarinesponge. Argentina , Geastrum wrightii onhumusinmixedforest. Australia , Golovinomyces glandulariae on Glandularia aristigera, Neoanungitea eucalyptorum on leaves of Eucalyptus grandis, Teratosphaeria corymbiicola on leaves of Corymbia ficifolia, Xylaria eucalypti on leaves of Eucalyptus radiata. Brazil, Bovista psammophila on soil, Fusarium awaxy on rotten stalks of Zea mays, Geastrum lanuginosum on leaf litter covered soil, Hermetothecium mikaniae-micranthae (incl. Hermetothecium gen. nov.)on Mikania micrantha, Penicillium reconvexovelosoi in soil, Stagonosporopsis vannaccii from pod of Glycine max. British Virgin Isles , Lactifluus guanensis onsoil. Canada , Sorocybe oblongispora on resin of Picea rubens. Chile, Colletotrichum roseum on leaves of Lapageria rosea. China, Setophoma caverna fromcarbonatiteinKarstcave. Colombia , Lareunionomyces eucalypticola on leaves of Eucalyptus grandis. Costa Rica, Psathyrella pivae onwood. Cyprus , Clavulina iris oncalcareoussubstrate. France , Chromosera ambigua and Clavulina iris var. occidentalis onsoil. French West Indies , Helminthosphaeria hispidissima ondeadwood. Guatemala , Talaromyces guatemalensis insoil. Malaysia , Neotracylla pini (incl. Tracyllales ord. nov. and Neotra- cylla gen. nov.)and Vermiculariopsiella pini on needles of Pinus tecunumanii. New Zealand, Neoconiothyrium viticola on stems of Vitis vinifera, Parafenestella pittospori on Pittosporum tenuifolium, Pilidium novae-zelandiae on Phoenix sp. Pakistan , Russula quercus-floribundae onforestfloor. Portugal , Trichoderma aestuarinum from salinewater. Russia , Pluteus liliputianus on fallen branch of deciduous tree, Pluteus spurius on decaying deciduouswoodorsoil. South Africa , Alloconiothyrium encephalarti, Phyllosticta encephalarticola and Neothyrostroma encephalarti (incl. Neothyrostroma gen. nov.)onleavesof Encephalartos sp., Chalara eucalypticola on leaf spots of Eucalyptus grandis × urophylla, Clypeosphaeria oleae on leaves of Olea capensis, Cylindrocladiella postalofficium on leaf litter of Sideroxylon inerme , Cylindromonium eugeniicola (incl. Cylindromonium gen. nov.)onleaflitterof Eugenia capensis , Cyphellophora goniomatis on leaves of Gonioma kamassi , Nothodactylaria nephrolepidis (incl. Nothodactylaria gen. nov. and Nothodactylariaceae fam. nov.)onleavesof Nephrolepis exaltata , Falcocladium eucalypti and Gyrothrix eucalypti on leaves of Eucalyptus sp., Gyrothrix oleae on leaves of Olea capensis subsp. macrocarpa , Harzia metro sideri on leaf litter of Metrosideros sp., Hippopotamyces phragmitis (incl. Hippopota- myces gen. nov.)onleavesof Phragmites australis , Lectera philenopterae on Philenoptera violacea , Leptosillia mayteni on leaves of Maytenus heterophylla , Lithohypha aloicola and Neoplatysporoides aloes on leaves of Aloe sp., Millesimomyces rhoicissi (incl. Millesimomyces gen. nov.) on leaves of Rhoicissus digitata , Neodevriesia strelitziicola on leaf litter of Strelitzia nicolai , Neokirramyces syzygii (incl. Neokirramyces gen. nov.)onleafspots o

Australian Aboriginal Ethnometeorology and Seasonal Calendars

This paper uses a cultural anthropological approach to investigate an indigenous Australian perspective on atmospheric phenomena and seasons, using data gained from historical records and ethnographic fieldwork. Aboriginal people believe that the forces driving the weather are derived from Creation Ancestors and spirits, asserting that short term changes are produced through ritual. By recognizing signals such as wind direction, rainfall, temperature change, celestial movements, animal behaviour and the flowering of plants, Aboriginal people are able to divide the year into seasons. Indigenous calendars vary widely across Australia and reflect annual changes within Aboriginal lifestyles