Technical experiences made with the litter bag test as required for the risk assessment of plant protection products in soil

Background, aim, and scope  The aim of this review was to assess the degree to which recent litter bag studies performed between 2002 and 2004 have followed the recommendations laid down in the ‘Effects of plant protection products on functional endpoints in soil (EPFES)’ guidance document and the Organisation for Economic Co-Operation and Development (OECD) Guidance Document on the Breakdown of Organic Matter in Litter bags (OECD, Guidance document on the breakdown of organic matter in litter bags, OECD series on testing and assessment, no 56, 36 pp, 2006), which can be required under European Union (EU) Directive 91/414/EEC (EU, Off J Eur Union, L230:1–32, 1991) for assessing the effect of plant protection products on non-target soil macro-organisms which contribute to the breakdown of organic matter. Materials and methods  The current review covers the analysis of key parameters of the litter bag method of a total of 29 litter bag studies conducted by six European Crop Protection Association companies. Results  The two validity criteria [i.e. 60% mass loss at the end of the study in the control and a maximum coefficient of variation of 40% for mass loss in the control plots (n = 6) during the first 6 months of the test] were met in all of the studies reviewed. In over half of the studies, more than 60% mass loss was reached in the control litter bags after about 6 months. Statistically significant effects on organic matter breakdown due to plant protection products were repeatedly observed during the first few months of the study conduct, including effects >10% up to >25% compared to the control. Discussion  The survey of 29 study reports—performed from May 2002 to May 2004—showed that litter bag studies are generally being performed following the ‘EPFES’ guidance document and the OECD guidance document no. 56. Transient, statistically significant effects >10% up to >25% compared to the control were determined repeatedly during the first few months of the study conduct, thus clearly indicating the sensitivity of the litter bag test system. Conclusions and perspectives  The litter bag study design is a valuable test system for the risk assessment of plant protection products on non-target soil macro-organisms which contribute to the breakdown of organic matter under EU Directive 91/414/EEC (EU, Off J Eur Union, L230:1–32, 1991). In general, it can be concluded that the litter bag test, as proposed by EPFES and the OECD guidance document, provides an integrative answer on the potential effects of plant protection products on organic matter breakdown in soil and can be continued to be used if the studies follow the recommendations as presented in the guidance documents closely.     

Mass Fingerprints of Tomatoes Fertilized with Different Nitrogen Sources Reveal Potential Biomarkers of Organic Farming

Plant Foods for Human Nutrition - Direct-injection electron spray ionization mass spectrometry (DIESI-MS) can be used to quantify the whole set of positive and negative ions in complex biological...     

Congenital neuropathy and dilution of feather melanin in nestlings of urban-breeding northern goshawks (Accipiter gentilis).

A pair of northern goshawks (Accipiter gentilis) breeding in a public park in the city center of Hamburg, Germany, raised 12 healthy and five aberrant offspring between 1996 and 2000. Aberrant nestlings (three males and two females) had pale silver-blue plumage and displayed severe locomotor disorders. Histopathologically, the defects were characterized by adendritic feather melanocytes and mild degeneration of the cerebellar white matter. Epidemiologic results were suggestive of a hereditary autosomal recessive defect, which may have originated from close inbreeding during the foundation of Hamburg's urban population of northern goshawks.     

Impact of sugarcane yellow leaf virus (ScYLV) on the carbohydrate status of sugarcane: Comparison of virus-free plants with symptomatic and asymptomatic virus-infected plants

The carbohydrate concentration of old and young sugarcane plants, either virus-free or infected by sugarcane yellow leaf virus, was compared. Internode lengths and fresh weights of symptomatic plants were reduced, but not the sucrose concentrations. Starch and sucrose concentration in green leaf tops of mature (18 months old) was the highest in asymptomatic plants followed by symptomatic, and then by virus-free plants. Carbohydrates increased during daytime by 5–20%. The carbohydrate concentration in leaves of young, 6 months old plants was much lower than in mature plants and it increased to 500% during daytime. Asymptomatic leaves had a higher level of carbohydrates, especially starch, from late afternoon until the end of the night, suggesting a reduction of assimilate export.     

First record of the wood boring weevil, <Emphasis Type="Italic">Pentarthrum huttoni</Emphasis>, in Austria (Coleoptera: Curculionidae)

The wood boring weevil, Pentarthrum huttoni Wollaston, is reported for the first time from Austria. It was recorded from coffins in the crypt of St. Michael’s church in the centre of Vienna. Extensive tunnelling of the larvae and surface damage by the adults caused disintegration of the historically significant wooden 18^th century coffins. Beetles were also detected in rotten cardboard on the loamy soil of the crypt. Infestation by this Cossonine weevil is promoted by the very damp conditions in the crypt, a consequence of the closure of ventilation funnels in the 1940s.     

Water use and water use efficiency of sweet corn under different weather conditions and soil moisture regimes

Plant growth and development are influenced by weather conditions that also affect water use (WU) and water use efficiency (WUE) and ultimately, yield. The overall goal of this study was to determine the impact of weather and soil moisture conditions on WU and WUE of sweet corn (Zea mays L. var rugosa). An experiment consisting on three planting dates was conducted in 2006 at The University of Georgia, USA. A sweet corn genotype sh2 was planted on March 27 under irrigated and rainfed conditions and on April 10 and 25 under irrigated conditions only. Soil moisture was monitored using PR2 probes. Rainfall and irrigation were recorded with rain gauges installed in the experimental area while other weather variables were recorded with an automatic weather station located nearby. A water balance was used to obtain the crop's daily evapotranspiration (ETc). WUE was calculated as the ratio of fresh and dry matter ear yield and cumulative ETc. The potential soil moisture deficit (Dp) approach was used to determine the crop's moisture stress. Results were analyzed using a single degree freedom contrast, linear regression, and the least significant difference. WU and WUE of sweet corn were both markedly affected by the intra-seasonal weather variability and Dp. For both variables, significant (p < 0.05) differences were found between planting dates under irrigated conditions and between the irrigated and rainfed treatments. WU was as high as 268 mm for the April 10 planting date under irrigated conditions and as low as 122 mm for the March 27 planting date under rainfed conditions. The maximum soil moisture deficit was reached at the milky kernel stage and was as high as 343 mm for the March 27 planting date under rainfed conditions and as low as 260 mm for the April 10 planting date under irrigated conditions. Further work should focus on the impact of the intra-seasonal weather variability and soil moisture conditions during different crop stages to determine critical periods that affect yield.     

蓝变真菌引起的欧洲云杉木质部解剖学特征及纤维素酶活性的变化

选择奥地利境内阿尔卑斯山健康欧洲云杉为对象,研究室内接种蓝变真菌(Ceratocystis polonica)引起的寄主树木韧皮部和木质部解剖学特征的变化,揭示蓝变真菌引起欧洲云杉枯萎的机制.结果表明:接种1周后的4株欧洲云杉的木质部组织内,蓝变区域显著增加,4～6周后蓝变区域不再增加;而在接种无菌琼脂的2株对照欧洲云杉的木质部组织内,没有检测到蓝变区域.采用生物化学分析和组织定位技术,确定接种真菌和无菌琼脂的欧洲云杉木质部区域纤维素酶的分布和活性变化.接种2周后剥皮取样检测,接种真菌的4株欧洲云杉的木质部组织内纤维素酶含量大幅度增加,其等电聚焦电泳显示明显的纤维素酶酶带;而在接种无菌琼脂的欧洲云杉木质部区域,纤维素酶含量分布较少,其等电聚焦电泳显示微弱的纤维素酶酶带.进一步证明蓝变真菌分泌的纤维素酶能利用寄主欧洲云杉木质部的纤维素,蓝变真菌是致死阿尔卑斯山境内欧洲云杉的重要病原菌.     

Soil aggregation,aggregate stability,organic carbon and nitrogen in different soil aggregate fractions under forest and shrub vegetation on the Loess Plateau,China

Revegetation has been reported as one of the most effective counter measures to reduce soil and water erosion on the Loess plateau in China. Soil aggregate stability and the distribution of organic carbon and nitrogen in different aggregate fractions would be affected by different plant communities. The objectives of this study were to elucidate the effects of different plant communities on soil aggregate stability and the distribution of organic carbon and nitrogen in different aggregate fractions in order to prove that the different plant covers enhance soil aggregate stability.