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Jacob J.,Institute for Plant Protection in Horticulture and Forests | Manson P.,Cheminova | Barfknecht R.,Bayer CropScience | Fredricks T.,Monsanto Corporation
Pest Management Science | Year: 2014

Common voles (Microtus arvalis) are common small mammals in some European landscapes. They can be a major rodent pest in European agriculture and they are also a representative generic focal small herbivorous mammal species used in risk assessment for plant protection products. In this paper, common vole population dynamics, habitat and food preferences, pest potential and use of the common vole as a model small wild mammal species in the risk assessment process are reviewed. Common voles are a component of agroecosystems in many parts of Europe, inhabiting agricultural areas (secondary habitats) when the carrying capacity of primary grassland habitats is exceeded. Colonisation of secondary habitats occurs during multiannual outbreaks, when population sizes can exceed 1000 individuals ha-1. In such cases, in-crop common vole population control management has been practised to avoid significant crop damage. The species' status as a crop pest, high fecundity, resilience to disturbance and intermittent colonisation of crop habitats are important characteristics that should be reflected in risk assessment. Based on the information provided in the scientific literature, it seems justified to modify elements of the current risk assessment scheme for plant protection products, including the use of realistic food intake rates, reduced assessment factors or the use of alternativee focal rodent species in particular European regions. Some of these adjustments are already being applied in some EU member states. Therefore, it seems reasonable consistently to apply such pragmatic and realistic approaches in risk assessments for plant protection products across the EU. © 2013 Society of Chemical Industry. Source

Schumacher J.,Institute for Plant Protection in Horticulture and Forests | Schumacher J.,Institute for Plant Protection in Horticulture and Forests | Kehr R.,University of Science and Arts of Iran | Leonhard S.,Bavarian State Institute of Forestry
Forest Pathology | Year: 2010

Ash dieback is an emerging disease of Fraxinus excelsior in Germany. To date, economical damage is significant in nurseries, which also contribute towards spread of the disease, but damage to forests is increasing. The study presents the results of mycological and histological investigations on three hundred 3-year-old nursery ash saplings. The infection rate by the causative pathogen was determined for bark, outer and inner xylem, the pith and also separately for the above-ground portion and root system of the plants. The invasion and colonization strategy of the fungus in the woody stem was examined. In addition, the presence of soil-borne Oomycetes as possible primary or accompanying causal organisms was investigated. The results verify the dominant role of Chalara fraxinea as a causal agent of ash dieback and rule out the role of Oomycetes in the disease process. We conclude that C. fraxinea is not primarily endophytic in nature and spreads very effectively in the central stem tissues, which enables colonization of the woody stem in all three dimensions. Infections arising in the upper part of plants can thus spread extensively to lower parts. © 2009 Blackwell Verlag GmbH. Source

Konig S.,Institute for Plant Protection in Horticulture and Forests | Schwenkbier L.,Institute of Photonic Technology | Schwenkbier L.,Friedrich - Schiller University of Jena | Pollok S.,Institute of Photonic Technology | And 8 more authors.
Plant Pathology | Year: 2015

A novel DNA-chip hybridization assay that uses the ras-related GTP-binding protein 1 gene (Ypt1) was developed for the identification of several devastating Phytophthora species. The hybridization was conducted in a portable microfluidic lab-on-a-chip device for fast and accurate detection of 40 Phytophthora, two Pythium and one Phytopythium species. Moreover, the functionality of the Ypt1 region was examined in comparison to an array for the internal transcribed spacer (ITS) region by in silico modelling. The difference in species-specific capture probe sequences was lower for the ITS than for the Ypt1 region. While ITS-probes of Phytophthora ramorum, Phytophthora fragariae and Phytophthora lateralis cross-reacted with up to 11 non-target species, Ypt1-probes were specific except for P. fragariae/Phytophthora rubi. First analyses of artificially inoculated Rhododendron leaves successfully demonstrated the usability of the respective capture probes for the Ypt1 and the ras-related plant protein Rab1a gene region. The on-chip hybridization enabled the detection of up to 1 pg μL-1 target DNA depending on the species examined. Due to the complementarity of ITS and Ypt1 genetic features, the use of multiple loci is recommended to identify targets of different taxonomic rank. © 2015 British Society for Plant Pathology. Source

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