Identification of Rhizoctonia solani AG 1-IB in Lettuce, AG 4 HG-I in Tomato and Melon, and AG 4 HG-III in Broccoli and Spinach, in Brazil

Fungi isolated in Brazil, from lettuce, broccoli, spinach, melon and tomato, were identified as Rhizoctonia solani. All lettuce isolates anastomosed with both AG 1-IA and IB subgroups and all isolates from broccoli, spinach, melon and tomato anastomosed with AG 4 subgroup HG-I, as well as with subgroups HG-II and HG-III. DNA sequence analyses of ribosomal internal transcribed spacers showed that isolates from lettuce were AG 1-IB, isolates from tomato and melon were AG 4 HG-I, and isolates from broccoli and spinach were AG 4 HG-III. The tomato isolates caused stem rot symptoms, the spinach, broccoli and melon isolates caused hypocotyl and root rot symptoms on the respective host plants and the lettuce isolates caused bottom rot. This is the first report on the occurrence in Brazil of R. solani AG 4 HG-I in tomato and melon, of AG 4 HG-III in broccoli and spinach and of AG 1-IB in lettuce.     

Development of a PCR test for the identification of Staphylococcus intermedius based on the 16S rDNA sequence

The development of a PCR assay based on the 16S ribosomal RNA gene (rDNA) sequence was carried out for the identification of Staphylococcus intermedius. Sixty-six strains of S. intermedius, 70 of Staphylococcus aureus and 2 of Staphylococcus hyicus were examined for the assay. The 16S rDNA, of which the PCR target fragment makes up 901 bp corresponding to the sequence data of the gene, was detected in all strains of S. intermedius, but it was not detected in any strains of either S. aureus or S. hyicus. These results suggest that the PCR allows a simple and precise identification of S. intermedius.     

Distribution of mecA-harboring staphylococci in healthy mares

The prevalence of staphylococci that harbor the mecA gene responsible for methicillin resistance was examined in healthy breeding mares. Staphylococci often cause diseases of horses such as metritis, keratitis, and abscess. Methicillin-resistant staphylococci would make antibiotic treatments ineffective, so it may be significant to know the distribution of mecA-harboring staphylococci in mares. Isolation of mecA-harboring staphylococci was achieved from nares and pasterns of 100 mares in Hokkaido, Japan. From 13% of the mares, mecA-harboring staphylococci, including 15 isolates of Staphylococcus sciuri and 3 of Staphylococcus lentus, were isolated. Isolates of S. sciuri were found to be genetically polyclonal by pulsed-field gel electrophoresis. These isolates produced no PCase and showed low or no resistance to beta-lactam and other classes of antibiotics. Distribution of staphylococcal species and levels of antibiotic resistance were found to be different between isolates from the present mares and those previously reported from riding-horses. Antibiotic pressure may lead to these differences. In addition, it appears that mecA-harboring S. sciuri may be native to horses.     

Five Years of Continuous Thaumetopoea processionea Monitoring: Tracing Population Dynamics in an Arable Landscape of South-Western Germany

Within this paper we summarize the results of the Thaumetopoea processionea monitoring at two observation sites and try to interpret population dynamics from 2006 to 2010 considering meteorological data. Furthermore, observations on the behaviour of neonates associated with oak budburst are presented and discussed. In 2007 large larval colonies occurred and population densities peaked. Massive defoliation and larval migration due to food shortage were observed regularly leading to reduced female moth fecundity. Unfavourable weather conditions probably abetted OPM population decline in spring 2008. Additionally oak budburst was delayed remarkably. More detailed observations on the hatching process and the behaviour of single colonies revealed increasing mortality after two and a half weeks of starvation. The 2009 results indicated another increase of population densities, but exceeded cool and humid weather conditions in May 2010 presumably prevented a new OPM outbreak. In accordance with previous studies egg parasitisation seems to play a minor role in OPM population dynamics.     

Modeling aerobic decomposition of rice straw during the off-rice season in an Andisol paddy soil in a cold temperate region of Japan: Effects of soil temperature and moisture

Submerged rice paddies are a major source of methane (CH₄) which is the second most important greenhouse gas after carbon dioxide (CO₂). Accelerating rice straw decomposition during the off-rice season could help to reduce CH₄ emission from rice paddies during the single rice-growth season in cold temperate regions. For understanding how both temperature and moisture can affect the rate of rice straw decomposition during the off-rice season in the cold temperate region of Tohoku district, Japan, a modeling incubation experiment was carried out in the laboratory. Bulk soil and soil mixed with 2% of δ¹³C-labeled rice straw with a full factorial combination of four temperature levels (?5 to 5, 5, 15, 25°C) and two moisture levels (60% and 100% WFPS) were incubated for 24 weeks. The daily change from ?5 to 5°C was used to model the freezing–thawing cycles occurring during the winter season. The rates of rice straw decomposition were calculated by (i) CO₂ production; (ii) change in the soil organic carbon (SOC) content; and (iii) change in the δ¹³C value of SOC. The results indicated that both temperature and moisture affected the rate of rice straw decomposition during the 24-week aerobic incubation period. Rates of rice straw decomposition increased not only with high temperature, but also with high moisture conditions. The rates of rice straw decomposition were more accurately calculated by CO₂ production compared to those calculated by the change in the SOC content, or in its δ¹³C value. Under high moisture at 100% WFPS condition, the rates of rice straw decomposition were 14.0, 22.2, 33.5 and 46.2% at ?5 to 5, 5, 15 and 25°C temperature treatments, respectively. While under low moisture at 60% WFPS condition, these rates were 12.7, 18.3, 31.2 and 38.4%, respectively. The Q₁₀ of rice straw decomposition was higher between ?5 to 5 and 5°C than that between 5 and 15°C and that between 15 and 25°C. Daily freezing–thawing cycles (from ?5 to 5°C) did not stimulate rice straw decomposition compared with low temperature at 5°C. This study implies that to reduce CH₄ emission from rice paddies during the single rice-growth season in the cold temperate regions, enhancing rice straw decomposition during the high temperature period is very important.     

Measurements of ozone deposition to a potato canopy

Potatoes are an important staple crop, grown in many parts of the world. Although ozone deposition to many vegetation types has been measured in the field, no data have been reported for potatoes. Such measurements, including the latent-heat flux, were made over a fully grown potato field in central Scotland during the summer of 2006, covering a 4-week period just after rainfall and then dry, sunny weather. The magnitude of the flux was typical of many canopies showing the expected diurnal cycles. Although the bulk-canopy stomatal conductance declined as the field dried out (～300 mmol-O₃ m^?2 s^?1 to ～70 mmol-O₃ m^?2 s^?1), the total ozone flux did not follow the same trend, indicating that non-stomatal deposition was significant. Over a dry surface non-stomatal resistance (R_ns) was 270–450 s m^?1, while over a wet surface R_ns was ～50% smaller and both decreased with increasing surface temperature and friction velocity. From the variation with relative humidity (RH) it is suggested that three processes occur on leaf surfaces: on a very dry surface ozone is removed by thermal decomposition, possibly enhanced by photolytic reactions in the daytime and so R_ns decreases as temperature increases; at 50–70% RH a thin film of liquid blocks the “dry” process and resistance increases; above 60–70% RH sufficient surface water is present for aqueous reactions to remove ozone and resistance decreases.     

亚马逊黑土及其黑碳颗粒中的真菌丰度和多样性互不相同

Amazonian Dark Earth (ADE) is a highly fertile soil of anthropogenic origin characterized by high levels of charred black carbon (BC).It is considered a model of fertility;however,knowledge on the fungal community structure and diversity inhabiting ADE and its BC particles is scarce.Fungal community structure and diversity of ADE and its BC from four sites under different land uses (three agricultural systems and a secondary pristine forest) in the Brazilian Central Amazon were evaluated by 18S rRNA gene pyrosequencing.Fungal communities in ADE and BC were dissimilar and showed differential abundances of fungal operational taxonomic units (OTUs).Estimated fungal species richness (abundance-based coverage estimate and Chao-1 index) and diversity estimators (Shannon and Simpson's reciprocal indices) were higher in ADE than in BC in all agricultural areas.No differences were observed in those parameters in ADE and BC samples from the secondary forest.Pezizomycotina fungi and OTUs assigned to Cordyceps confragosa,Acremonium vitellinum,Camarops microspora,and Hirsutella rhossiliensis were more abundant in BC particles than in ADE.These findings represent a breakthrough in our understanding of fungal communities in BC particles from ADE,and will be valuable in future studies considering biochar application in soil.     

Surveillance and characterization of Newcastle disease viruses isolated from northern pintail (Anas acuta) in Japan during 2006-09

A total of 38 Newcastle disease virus (NDV) isolates were obtained from 6060 fecal samples from northern pintail (Anas acuta) ducks collected in the Tohoku district in Japan during 2006-09. One isolate from each sampling location and date was selected for a total of 38 isolates, then 15 of these were characterized for their pathogenicity by mean death time of minimum lethal dose (MDT/MLD) using chicken embryos and by plaque formation on chicken embryo fibroblasts. Furthermore, nine isolates were randomly selected from these 15 isolates, and the fusion protein genes were sequenced to characterize amino acid sequences around the cleavage site. All 15 were confirmed to be nonvirulent by MDT/MLD test, and nine isolates were also confirmed as nonvirulent by the cleavage site of the fusion protein 112G/E-K/R-Q-G/E-R*L117 that was specific for nonvirulent NDVs. The characteristics of nine isolates identified by phylogenic analysis of the fusion protein gene indicated that the isolates belong to genotype I or II. In addition, we also isolated 68 avian influenza viruses and 28 other hemagglutinating viruses. Our data indicate that northern pintails are subclinically infected by, perpetuate, and distribute NDV along with different subtypes of avian influenza viruses and other hemagglutinating viruses during their migrations across vast areas over the Northern Hemisphere to Japan.