Biological control of green mould on <Emphasis Type="Italic">Agaricus bisporus</Emphasis> by a native <Emphasis Type="Italic">Bacillus subtilis</Emphasis> strain from mushroom compost

Fifty bacterial isolates obtained from compost were tested in vitro against the causal agents of green mould in Agaricus bisporus. Isolate B-38 which induced 48.08% in vitro growth inhibition of T. harzianum T54 and 52.25% of T. aggressivum f. europaeum T77 was identified as Bacillus subtilis, based on 16S rDNA sequence and used in mushroom growing room experiments. B. subtilis B-38 did not decrease mycelial growth rate of Agaricus bisporus A15 in mushroom compost in glass tubes. After applying prochloraz-manganese, B. subtilis B-38 and B. subtilis QST 713, no significant differences in BE values among treatments were found concerning both total yield and the weight of healthy mushrooms. Statistical analyses showed that only inoculation significantly influenced the healthy mushroom yield. In plots inoculated with T. harzianum T54 disease incidence was significantly lower after treatments with prochloraz-manganese (11.81%), B. subtilis QST 713 (12.26%) and B. subtilis B-38 (14.19%) compared to the control (28.16%), as well as in plots inoculated with T. aggressivum f. europaeum T77 11.88%, 12.2% and 15.03%, respectively, in comparison with the control (23.47%). Statistically significant differences were not found among the efficacy values of tested bio-fungicides based on B. subtilis and the commercial fungicide prochloraz-manganese suggesting the use of B. subtilis B-38 and B. subtilis QST 713 as good alternatives to chemical fungicides.     

Response of fungal and plant communities to management-induced overstorey changes in montane forests of the Western Carpathians

The effect of forest management on biodiversity is a crucial issue for sustainable forestry and nature conservation. However, the ways in which management affects macrofungal and plant communities and diversity of mountain temperate forests still remain poorly understood. We performed a random sampling stratified by stand age and stand type on the sites of temperate montane fir–beech forests. Diversity of macrofungi and the vascular plant understorey in beech- and spruce-dominated managed stands was investigated and compared to primeval forests located in the Po?ana Biosphere Reserve, Western Carpathians. Both the vascular plant and the macrofungal communities were altered by management, and the response of the macrofungal species (especially wood-inhabiting fungi) was more pronounced in terms of species composition change. Species turnover evaluation seems to be an important tool of forest natural status assessment, because alpha diversity did not change as much as species composition. Certain species of Carpathian primeval forests were confirmed as good indicators for natural forest change; others were proposed. Species pool and mean number of species per plot were the highest in unmanaged fir–beech forests, and species diversity significantly decreased in spruce plantations. The number of species decreased significantly due to the change of canopy tree species composition only in the macrofungal communities. As an outcome for forest management, we recommend keeping mixed forests involving all natural tree species and providing at least a minimal amount of dead wood necessary for wood-inhabiting organisms and leaving some area of unmanaged natural forests within complexes of managed stands.     

Identifying key factors affecting coffee leaf rust incidence in agroforestry plantations in Peru

Coffee leaf rust (CLR), caused by Hemileia vastarix, is one of the most serious diseases of coffee plantations and cause great losses in coffee production. We aimed to examine coffee varieties, shade, age of coffee plants, coffee plant density and soil properties in relation to CLR infection. To do this, we established a total of 75 plots in three agroforestry coffee plantations in the central Peruvian Amazon. We gathered data there in 2011 (dry season) on the presence/absence of CLR; coffee variety; age and density of coffee plants, and also took hemispherical photographs to determine canopy openness. In 2014 (wet season), we again gathered data on the same variables. In 2012, we collected soil samples from a subset of the plots. At all plantations, coffee variety had a significant effect on CLR incidence, with the Catimor variety infected less frequently than Caturra. Coffee plant age had a significant positive effect on CLR incidence. Increasing coffee density also increased CLR incidence for some of the studied plantations/seasons. Comparing those plots from which data were collected in the dry and wet seasons, we found that CLR presence was significantly higher in the wet season. The effect of shade on CLR incidence was not clear. Catimor and Caturra varieties showed opposite trends of CLR incidence in response to shade quantity in most cases (Caturra variety CLR incidence was decreasing with shading increase and Catimor CLR incidence decreasing with decreasing shading). Finally, the soil properties did not affect CLR incidence.     

Liming alters body size distribution in a community of epigeic spiders in birch forest (<Emphasis Type="Italic">Betula pendula</Emphasis> Roth)

Key message

Liming, an ameliorative method for acidified forest soils, affected the relative abundance of prey of ground-hunting spiders and consequently reduced densities of functionally similar species of these predators.

Context

Liming, an ameliorative method for acidified forest soils, may modify the structure of an arthropod community by altering the soil characteristics and/or the availability of food resources.

Aims

We investigated the effect of liming on the community structure of ground-hunting spiders in a birch forest.

Methods

We established six experimental birch stand plots. Each stand was exposed to one of three experimental treatments: control, 1.5 t/ha, or 3 t/ha of dolomitic limestone. We collected spiders using pitfall traps during 5 years. We characterized the community in terms of activity density, species richness, community-weighted mean body size, and functional diversity and evenness in body size. We further investigated the potential links through which the liming might affect spiders, namely soil characteristics, effect of liming on birch, and densities of potential prey.

Results

The commonly used dosage of 3 t/ha reduced densities of functionally similar species which led to the reduced functional evenness in body size and increased functional divergence in body size. Liming increased soil pH only slightly but decreased the densities of spiders’ preferred prey.

Conclusion

The liming affected the community of ground-hunting spiders, at least partially, through reduced densities of their preferred prey.

     

Viruses affecting tomato crops in Serbia

In a two-year survey (2011–2012), 3220 samples were collected and analyzed in order to determine the presence and distribution of viruses in tomato crops at 56 localities of 18 districts in Serbia. Out of 12 viruses tested, Cucumber mosaic virus (CMV), Potato virus Y (PVY), Alfalfa mosaic virus (AMV), Tomato spotted wilt virus (TSWV), Tomato mosaic virus (ToMV) and Tobacco mosaic virus (TMV) were detected in 42.1, 40, 11, 8.6, 2.3 and 1.3% of the total tested samples, respectively. The results revealed that CMV was prevalent in 2011 and PVY in 2012. CMV and PVY, apart from being predominant, were also the most widespread viruses. In general, single infections were the most frequent type of infection. Additionally, the most common mixed infections were double infections and the most prevalent combination was CMV and PVY. In 2011, the incidence of diseases and the percentage of all infection types were significantly higher than in 2012. Furthermore, in 2011, regardless of total single infections being prevalent compared to mixed infections, two prevailing viruses were commonly detected in mixed infections. The additional molecular testing of ELISA-negative samples using virus specific primers did not reveal the presence of Pepino mosaic virus (PepMV), Tomato yellow leaf curl virus (TYLC), Tomato infections chlorosis virus (TICV) and Tomato chlorosis virus (ToCV).     

Local diversity of native arbuscular mycorrhizal symbionts differentially affects growth and nutrition of three crop plant species

Intact whole native AMF communities occurring across a 100-m-long field were used for the evaluation of plant performance, as determined by the actual fungal species colonizing host roots. The soil from distinct plots within a “hot spot” field was collected to set up 54 experimental units where three different plant species were grown, in order to test whether the whole native AMF communities were able to differentially affect plant growth, to assess the genetic identity of the AMF actually colonizing the tested plants and to analyse their community composition in the different hosts. Molecular analyses revealed that plant growth and nutrition of the crop plants were differentially affected by the diverse native arbuscular mycorrhizal communities colonizing the roots of the three plants, whose performance varied depending on the identity of plant hosts and fungal symbionts, more than on a rich and diversified AMF community. Such results, improving our understanding of AMF distribution at the local scale, represent a starting point allowing the selection, isolation and characterization of the most efficient AMF assemblages to be used as inoculants in sustainable food production systems.     

Examining the Effects of the Destroying Ammunition,Mines and Explosive Devices on the Presence of Heavy Metals in Soil of Open Detonation Pit; Part 2: Determination of Heavy Metal Fractions

As a result of the destruction of ammunition, mines, and explosive devices by the method of open detonation, the increased concentration of heavy metals is often recorded in the soil of military polygons, which is a serious ecological problem. However, in order to determine the potential risk of such locations to the environment, it is necessary to determine, in addition to the total content, the forms in which the metals are present. In this paper, a sequential extraction method was used to analyze the six fractions of five heavy metals (cadmium, lead, nickel, copper, and zinc) in the soil of the polygon for destruction of ammunition, mines, and explosive devices. Samples were collected from the place of direct detonation (so-called pits) and from the edge of the pit. The aim of this research is determination of metal speciation in order to obtain a better insight in their mobility and risk arising from this. The results showed that heavy metals are predominantly present in the residual, oxide, and organic fractions. Cd and Cu were also significantly present in the mobile fractions due to conducted activities on the polygon. To assess the potential environmental risk of soil, the risk assessment code (RAC) and individual (ICF) and global (GCF) contamination factors were used. According to the RAC, the mobility and bioavailability of the analyzed heavy metals decreases in the following order: Cd?&gt;?Cu?&gt;?Zn?&gt;?Pb?&gt;?Ni. ICF results show low to moderate risk, while GCF results show low risk in terms of heavy metal contamination in the examined area.     

Contribution of organic amendments to soil organic matter detected by thermogravimetry

Sustainable soil management requires reliable and accurate monitoring of changes in soil organic matter (SOM). However, despite the development of improved analytical techniques during the last decades, there are still limits in the detection of small changes in soil organic carbon content and SOM composition. This study focused on the detection of such changes under laboratory conditions by adding different organic amendments to soils. The model experiments consisted of artificially mixing soil samples from non‐fertilized plots of three German long‐term agricultural experiments in Bad Lauchstädt (silty loam), Grossbeeren (silty sand), and Müncheberg (loamy sand) with straw, farmyard manure, sheep faeces, and charcoal in quantities from 3 to 180 t ha^?1 each. In these mixtures we determined the organic carbon contents by elemental analysis and by thermal mass losses (TML) determined by thermogravimetry. The results confirmed the higher reliability of elemental analysis compared to TML for organic carbon content determination. The sensitivity of both methods was not sufficient to detect the changes in organic carbon content caused by small quantities of organic amendments (3 t ha^?1 or 0.1–0.4 g C kg^?1 soil). In the case of elemental analysis, the detectability of changes in carbon content increased with quantities of added amendments, but the method could not distinguish different types of organic amendments. On the contrary, the based on analysis of degradation temperatures, the TML allowed this discrimination together with their quantitative analysis. For example, added charcoal was not visible in TML from 320 to 330°C, which is used for carbon content determination. However, increasing quantities of charcoal were reflected in a higher TML around 520°C. Furthermore, differences between measured (with TML_110–550) and predicted mass loss on ignition using both organic carbon (with TML₃₃₀) and clay contents (with TML₁₄₀) were confirmed as a suitable indicator for detection of organic amendments in different types of soils. We conclude that thermogravimetry enables the sensitive detection of organic fertilizers and organic amendments in soils under arable land use.     

The prospects of silver fir (Abies alba Mill.) and Norway spruce (Picea abies (L.) Karst) in mixed mountain forests under various management strategies,climate change and high browsing pressure

European Journal of Forest Research - In the Dinaric Mountains, the future of silver fir and Norway spruce appears to be uncertain, especially given the threat of climate change to both species and...     

The effect of N and NaCl on growth,yield, and nitrate content of salad rocket (Eruca sativa Mill.)

Hydroponic production of rocket as a salad vegetable has become increasingly important in recent years. Rocket is known to be a high nitrate (NO₃^–)-accumulating vegetable, which can be grown throughout the year. In the present study, rocket was grown in a floating hydroponic system at three levels of nitrogen (N) and sodium chloride (NaCl). The highest yield was obtained at 14 mM N, whereas the yield was lower at 20 mM and 40 Mm NaCl. Leaf elongation was more sensitive to salinity than leaf differentiation. Adding NaCl to the nutrient solution increased the relative chlorophyll content. Na⁺ and Cl^– concentrations increased as salinity increased. NO₃^? levels in fresh biomass increased with increased amounts of NO₃^? in the nutrient solution, and plants at 18 mM N were able to maintain a higher NO₃^? : Cl^? ratio than those at 10 mM N.