Jörg Samietz

Universitätsklinikum Jena, Jena, Thuringia, Germany

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Publications (55)64.11 Total impact

  • B. Graf · H. U. Höpli · H. Höhn · J. Samietz
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    ABSTRACT: The effects of temperature on egg and larval development of Grapholita lobarzewskii Nowicki (Lepidoptera: Tortricidae) were studied under controlled conditions to complement the basis for phenological forecasting and thus to optimize the timing of monitoring and control measures with respect to sustainable pest management. Egg development lasted on average 28.1 days at 12.7 °C and 5.5 days at 26.1 °C. Egg mortality was generally low, varying between 12 and 14% within a temperature range of 12.7-22.0 °C, but slightly increased to 20% at 26.1 °C. For egg development, a lower thermal threshold of 9.7 °C and a thermal constant of 90.6 degree days were established. Larval development took on average 76.0 days at 12.7 °C and 21.5 days at 26.1 °C. Larval mortality was 51% at 12.7 °C but only 6-12% at temperatures above 17 °C. The lower thermal threshold and the thermal constant for larval development were 7.6 °C and 389.2 degree days, respectively. Final larval weight increased with temperature from 18.6 mg at 12.7 °C to a maximum of 23.9 mg at 22.0 °C. Based on mortality rates, the optimal temperature range was between 12.7 and 22.0 °C for egg development and between 17.1 and 22.0 °C for larval development, which was confirmed based on the weight of fully grown larvae. These biological parameters of egg and larval development enabled us to parameterise a phenology model for G. lobarzewskii, which was incorporated into an existing decision support system for fruit pests. Precise forecasts of pest phenology facilitate the optimal timing of monitoring and control measures, improve their efficiency, and thereby contribute to sustainable crop protection.
    No preview · Article · Jan 2016 · Entomologia Experimentalis et Applicata
  • S. Stoeckli · J. Samietz
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    ABSTRACT: Plant phenology has a strong sensitivity to temperature and therefore high relevance to document responses to climate change. Flowering phenology plays a major role as a relevant set-point (i.e., biofix) in tree fruit pest and disease modelling. Projected climate change largely affects the range and phenology of pests and diseases, which requires adaptations of plant protection strategies to maintain their sustainability. The aim of the present study was (1) to elucidate a change in apple fruit phenology during the last decades and (2) to develop a simple heating model that only relies on present-year accumulated temperature sums. The results showed that apple flowering advanced on average 3.1 days/decade from 1960 to 2010. From 1981 to 2011, full bloom even advanced on average 5.1 days/decade. These shifts are similar to other phenological events of temperate deciduous trees reported in literature. For beginning of flowering, full bloom, and flowering termination (BBCH 60, 65, 69), the variation in temperature sums (coefficient of variation) was smallest for forcing day of year (DOY) 45 and forcing temperature threshold of 0°C. The corresponding temperature sums from DOY 45 were 10368 degree-hours (°h) (BBCH 60), 12546°h (BBCH 65), and 15914°h (BBCH 69). For BBCH 60 and 65, the validation of the simplified heating model for apple flowering revealed a good relationship between observed DOY and simulated DOY across all years and sites. Those models are simple, do not rely on data of the previous year and are therefore easily applicable in climate change scenarios, for pest and disease simulations.
    No preview · Article · Feb 2015 · Acta horticulturae
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    ABSTRACT: Climate change in temperate regions will lead to higher and more extreme temperature distributions; however, its impact on pests and their control strategies is rarely investigated in detail. One reason is the problem of downscaling climate predictions to the temporal and spatial scale of pest life cycles. In the present study, we have closed that gap by impact modelling on hourly scale and downscaling on spatial scale, by adapting a stochastic weather generator (WG) for pest modelling. Thereby, the codling moth, Cydia pomonella, serves as a relevant model species for a key pest with multiple generations per year that, already under the present climate, requires intensive efforts to control. Stochastic weather generation, followed by a resampling approach, provided hourly synthetic weather data for 10 meteorological sites in Switzerland under future climate conditions (2045-2074). Synthetic weather was analysed by a phenology model implemented in the forecasting system SOPRA. The results showed significant shifts to earlier dates in codling moth phenological events in Swiss apple orchards, increased magnitude of the 2nd generation, less overlap between stages, and a bigger risk for an additional 3rd generation. Shifts in phenology and magnitude of later generations require adaptations of plant protection regimes to maintain their sustainability, as we illustrate in the present paper, specifically for the strategies in codling moth control. In general, however, methodologies may easily be adapted in further pest and disease combinations and cropping systems.
    No preview · Article · Feb 2015 · Acta horticulturae
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    Joerg Samietz · Jens Schumacher · Klaus Reinhardt
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    ABSTRACT: Bush crickets are a model group for testing hypotheses in sexual selection, but much of the information is based on laboratory observations on wingless or short-winged species, which may restrict their generality. Here we describe aspects of the mating behaviour of the long-winged European bush cricket Phaneroptera falcata (Poda, 1761). Both in the laboratory and the field, diel calling followed a normal, though slightly left-skewed distribution, peaking about three hours after sunset or lights-off. Under bright greenhouse conditions, when the light was suddenly switched off, calling occurred only after the onset of darkness. Decreasing light intensity may trigger the start of calling activity. In the field, calling decreased from midnight onwards, which may be related to a decrease in temperature. The sequence of events during copulation was identical in the laboratory and the field. However, in two of 14 copulations documented in the field, a pre-copulatory behaviour was observed that resembled the putative removal and ingestion of rival sperm Previous suggestions that P. falcata (Poda) is monogamous are rejected on the basis of both laboratory and field results. In the laboratory males and females mated every 2.3 and 3.6 days, respectively. We introduce a simple way to calculate the average frequency of mating in the field, based on the observation that at any one time 3% of all the individuals are recorded mating and copulation lasts 15 min. We estimate that on average P. falcata (Poda) mates once per day. More generally, our results show it is important for evolutionary conclusions to measure behaviourial data in the field.
    Full-text · Article · May 2014 · European Journal of Entomology
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    ABSTRACT: We examined the attack of a potentially invasive tropical insect on a non-optimal temperate zone host and tested the hypothesis that variation in plant secondary metabolites and/or locally-grown host plant cultivars could shape agroecosystem resilience in a region undergoing climatic change. We studied the phytophagous fruit fly Anastrepha ludens (Diptera: Tephritidae) and 18 apple cultivars most of which vary significantly in total content of phenolic compounds. High content of phenolic compounds significantly increased egg or larval mortality whereas cultivars exhibiting low content were severely infested. Intermediate concentrations resulted in pupal malformation and delayed immature development. These results provide a valuable insight into biotic factors that contribute to environmental resilience to an invasive species that could expand its geographical range in response to global climate change. They also highlight the importance of protecting ancestral or locally-grown apple cultivars as sources of genes for breeding programs directed at restoring the ability of crops to defend themselves against emerging pests or to cope with changing environmental conditions.
    Full-text · Article · Mar 2014 · Agriculture Ecosystems & Environment
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    ABSTRACT: Background Rapid and reliable identification of quarantine pests is essential for plant inspection services to prevent introduction of invasive species. For insects, this may be a serious problem when dealing with morphologically similar cryptic species complexes and early developmental stages that lack distinctive characters useful for taxonomic identification. DNA based barcoding could solve many of these problems. The standard barcode fragment, an approx. 650 base pairs long sequence of the 5′end of the mitochondrial cytochrome oxidase I (COI), enables differentiation of a very wide range of arthropods. However, problems remain in some taxa, such as Tephritidae, where recent genetic differentiation among some of the described species hinders accurate molecular discrimination. Results In order to explore the full species discrimination potential of COI, we sequenced the barcoding region of the COI gene of a range of economically important Tephritid species and complemented these data with all GenBank and BOLD entries for the systematic group available as of January 2012. We explored the limits of species delimitation of this barcode fragment among 193 putative Tephritid species and established operational taxonomic units (OTUs), between which discrimination is reliably possible. Furthermore, to enable future development of rapid diagnostic assays based on this sequence information, we characterized all single nucleotide polymorphisms (SNPs) and established “near-minimal” sets of SNPs that differentiate among all included OTUs with at least three and four SNPs, respectively. Conclusions We found that although several species cannot be differentiated based on the genetic diversity observed in COI and hence form composite OTUs, 85% of all OTUs correspond to described species. Because our SNP panels are developed based on all currently available sequence information and rely on a minimal pairwise difference of three SNPs, they are highly reliable and hence represent an important resource for developing taxon-specific diagnostic assays. For selected cases, possible explanations that may cause composite OTUs are discussed.
    Full-text · Article · May 2013 · BMC Evolutionary Biology
  • H. Kutinkova · V. Dzhuvinov · J. Samietz
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    ABSTRACT: The peach twig borer (PTB), Anarsia lineatella Zell., and the oriental fruit moth Cydia molesta (OFM) Busck are the main pests of apricot in Bulgaria. The main objective of this study was to test the possibility of using mating disruption (MD) as an alternative method to control both pests. The experiment was carried out in an isolated apricot orchard, established in spring 2003 in north-east Bulgaria. In the years 2008-2009 mating disruption (MD) was tested using Ecodian Combi CM+AL pheromone dispensers (ISAGRO SpA, Italy). Dispensers were installed twice per season at 60-day intervals. In both years, MD totally suppressed captures of male moths in orfamone and anemone baited traps in the trial plot. Fruit damage in the MD-treated plot was low, from 0 to 0.1-0.2% at harvest. The results have confirmed that applications of Ecodian Combi CM+AL dispensers can provide more effective control of peach twig borer and oriental fruit moth than the conventional protection programme commonly applied in Bulgaria and should be implemented in commercial apricot production. This friendly approach to controlling peach twig borer and oriental fruit moth is in line with the recent EU recommendations that take care of preservation of the natural environment and of production of healthy fruits, with no pesticide residues.
    No preview · Article · Nov 2012 · Acta horticulturae
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    ABSTRACT: Crop protection in general and apple crop protection in particular often rely on pesticides, although several alternative pest management measures are available. In this context European agricultural policy requires the implementation of Integrated Pest Management (IPM) by 2014. Within IPM, more than one strategy can be practiced but selecting the most sustainable strategy is difficult because it requires simultaneous assessment of multiple environmental and economic aspects or attributes. Here, we introduce the SustainOS methodology for sustainability assessment of orchard systems, and we evaluate its usefulness in a case study involving four crop protection strategies in apple orchards of five European regions. SustainOS is an iterative, multi-attribute approach for defining and rating the sustainability of crop protection strategies in comparative studies. It consists of a transparent system-description tool including context, target, and crop protection parameters. The parameters are used as input data for life cycle assessment, environmental risk assessment, and full-cost calculations. The various results from these quantitative assessments are used to generate a multi-attribute rating with respect to ecological and economic sustainability. We demonstrate how the quantitative results can be translated into rating classes. By applying the SustainOS methodology, we show that the ecological sustainability for all five regions can potentially be improved by implementing alternative crop protection measures currently available. We also report that, by increasing yield, yield stability, and fruit quality, implementation of IPM can improve the economic situation of apple growers. Because of its transparency, SustainOS facilitated the collaborative development and comparison of crop protection strategies for sustainable orchard systems by an international network of agronomists, economists, and environmental scientists.
    Full-text · Article · Nov 2012 · Agricultural Systems
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    Jörg Samietz · Günter Köhler
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    ABSTRACT: Evolutionary theory predicts trade-offs between fecundity and mobility, but there is substantial lack of empirical evidence if and how basic mobility relates to fitness costs. In a field experiment, we investigated fecundity costs of mobility in a non-migratory, wing-monomorphic grasshopper, Stenobothrus lineatus, and at the same time tested for possible effects of reproductive state (egg-load) on the mobility. For 10 days, body weight and activity radius of 60 females were recorded daily and oviposition events were inferred from abrupt weight losses. We found a strong and significant relationship between the individual mobility and the time between egg pods laid (interpod period). Individual egg-laying was reduced by a rate of 0.36 eggs per day with each meter increase in mean daily activity radius. The trade-off was not biased by the size of the females, that is, constitution did not positively influence both offspring number and mobility. Egg-load had no significant influence on the individual distances travelled. We could demonstrate that mobility - as induced and selected for by foraging, thermoregulation, predator escape, shelter seeking, and reproduction - can be directly paid off by fecundity. This direct consequence of mobility on individual fitness was detected for the first time in a walking insect.
    Preview · Article · Nov 2012 · Ecology and Evolution
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    ABSTRACT: Monthly weather forecasts (MOFCs) were shown to have skill in extratropical continental regions for lead times up to 3 weeks, in particular for temperature and if weekly averaged. This skill could be exploited in practical applications for implementations exhibiting some degree of memory or inertia toward meteoro-logical drivers, potentially even for longer lead times. Many agricultural applications fall into these categories because of the temperature-dependent development of biological organisms, allowing simulations that are based on temperature sums. Most such agricultural models require local weather information at daily or even hourly temporal resolution, however, preventing direct use of the spatially and temporally aggregated in-formation of MOFCs, which may furthermore be subject to significant biases. By the example of forecasting the timing of life-phase occurrences of the codling moth (Cydia pomonella), which is a major insect pest in apple orchards worldwide, the authors investigate the application of downscaled weekly temperature anomalies of MOFCs for use in an impact model requiring hourly input. The downscaling and postprocessing included the use of a daily weather generator and a resampling procedure for creating hourly weather series and the application of a recalibration technique to correct for the original underconfidence of the forecast occurrences of codling moth life phases. Results show a clear skill improvement of up to 3 days in root-mean-square error over the full forecast range when incorporating MOFCs as compared with deterministic benchmark forecasts using climatological information for predicting the timing of codling moth life phases.
    Full-text · Article · Sep 2012 · Journal of Applied Meteorology and Climatology
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    ABSTRACT: Global warming will lead to earlier beginnings and prolongation of growing seasons in temperate regions and will have pronounced effects on phenology and life-history adaptation in many species. These changes were not easy to simulate for actual phenologies because of the rudimentary temporal (season) and spatial (regional) resolution of climate model projections. We investigate the effect of climate change on the regional incidence of a pest insect with nearly worldwide distribution and very high potential for adaptation to season length and temperature--the Codling Moth, Cydia pomonella. Seasonal and regional climate change signals were downscaled to the hourly temporal scale of a pest phenology model and the spatial scale of pest habitats using a stochastic weather generator operating at daily scale in combination with a re-sampling approach for simulation of hourly weather data. Under future conditions of increased temperatures (2045-2074), the present risk of below 20% for a pronounced second generation (peak larval emergence) in Switzerland will increase to 70-100%. The risk of an additional third generation will increase from presently 0-2% to 100%. We identified a significant two-week shift to earlier dates in phenological stages, such as overwintering adult flight. The relative extent (magnitude) of first generation pupae and all later stages will significantly increase. The presence of first generation pupae and later stages will be prolonged. A significant decrease in the length of overlap of first and second generation larval emergence was identified. Such shifts in phenology may induce changes in life-history traits regulating the life cycle. An accordingly life-history adaptation in photoperiodic diapause induction to shorter day-length is expected and would thereby even more increase the risk of an additional generation. With respect to Codling Moth management, the shifts in phenology and voltinism projected here will require adaptations of plant protection strategies to maintain their sustainability.
    Full-text · Article · Apr 2012 · PLoS ONE
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    ABSTRACT: Given the repercussions of pests and diseases on agricultural production, detailed forecasting tools have been developed to simulate the degree of infestation depending on actual weather conditions. The life cycle of pests is most successfully predicted if the micro-climate of the immediate environment (habitat) of the causative organisms can be simulated. Sub-seasonal pest forecasts therefore require weather information for the relevant habitats and the appropriate time scale. The pest forecasting system SOPRA (www.sopra.info) currently in operation in Switzerland relies on such detailed weather information, using hourly weather observations up to the day the forecast is issued, but only a climatology for the forecasting period. Here, we aim at improving the skill of SOPRA forecasts by transforming the weekly information provided by ECMWF monthly forecasts (MOFCs) into hourly weather series as required for the prediction of upcoming life phases of the codling moth, the major insect pest in apple orchards worldwide. Due to the probabilistic nature of operational monthly forecasts and the limited spatial and temporal resolution, their information needs to be post-processed for use in a pest model. In this study, we developed a statistical downscaling approach for MOFCs that includes the following steps: (i) application of a stochastic weather generator to generate a large pool of daily weather series consistent with the climate at a specific location, (ii) a subsequent re-sampling of weather series from this pool to optimally represent the evolution of the weekly MOFC anomalies, and (iii) a final extension to hourly weather series suitable for the pest forecasting model. Results show a clear improvement in the forecast skill of occurrences of upcoming codling moth life phases when incorporating MOFCs as compared to the operational pest forecasting system. This is true both in terms of root mean squared errors and of the continuous rank probability scores of the probabilistic forecasts vs. the mean absolute errors of the deterministic system. Also, the application of the climate conserving recalibration (CCR, Weigel et al. 2009) technique allows for successful correction of the under-confidence in the forecasted occurrences of codling moth life phases. Reference: Weigel, A. P.; Liniger, M. A. & Appenzeller, C. (2009). Seasonal Ensemble Forecasts: Are Recalibrated Single Models Better than Multimodels? Mon. Wea. Rev., 137, 1460-1479.
    No preview · Article · Apr 2012
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    ABSTRACT: The codling moth (CM) Cydia pomonella (L.), is the main pest of pome fruits worldwide, including Bulgaria. Its larvae cause severe damage to apples, pears, quinces and walnuts. Resistance of CM to commonly used conventional insecticides (organophosphates and pyrethroids), which has already been noted in Bulgaria, as well as restrictions on insecticide use imposed by EU regulations, have encouraged a new approach to the control of this pest. Alternative methods have been extensively tested during the last few years. Mating disruption appears as a very promising solution. CheckMate̊ CM-F is a sprayable microencapsulated sex pheromone formulation, containing the active ingredient (E,E)-8,10-dodecadien-1-ol (14.3%), has recently been introduced into many countries for the mating disruption of codling moth. Trials comparing this encapsulated sprayable pheromone against conventional CM control practices were carried out during two consecutive years (2007-2008), in central north Bulgaria. The microencapsulated pheromone (183 ml of CheckMate̊ CM-F per ha) was applied 6 times per season at 22-25 day intervals. In both years, it totally suppressed captures of male moths in codlemone baited traps in the trial plot. The fruit damage in the pheromone-treated plot stayed at a very low level, amounting at harvest 0.13% in 2007 and 0.3% in 2008 and the overwintering CM population in autumn was 0.55 and 0.65 larvae per tree in 2007 and 2008, respectively. In contrast, in the reference orchard, treated 9-11 times per season with conventional insecticides, fruit damage reached 2.3% in 2007 and 2.7% in 2008 and the hibernating CM population was 1.05 in 2007 and 1.85 larvae per tree in 2008. In conclusion, it was evident that applications of Check Mate̊ CM-F can provide an effective control of codling moth, with better results than the conventional protection program in Bulgaria and should be implemented in commercial apple production.
    No preview · Article · Mar 2012 · Acta horticulturae
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    ABSTRACT: As a consequence of current and projected climate change in temperate regions of Europe, agricultural pests and diseases are expected to occur more frequently and possibly to extend to previously not affected regions. Given their economic and ecological relevance, detailed forecasting tools for various pests and diseases have been developed, which model their phenology depending on actual weather conditions and suggest management decisions on that basis. Assessing the future risk of pest-related damages requires future weather data at high temporal and spatial resolution. Here, we use a combined stochastic weather generator and re-sampling procedure for producing site-specific hourly weather series representing present and future (1980-2009 and 2045-2074 time periods) climate conditions in Switzerland. The climate change scenarios originate from the ENSEMBLES multi-model projections and provide probabilistic information on future regional changes in temperature and precipitation. Hourly weather series are produced by first generating daily weather data for these climate scenarios and then using a nearest neighbor re-sampling approach for creating realistic diurnal cycles. These hourly weather series are then used for modeling the impact of climate change on important life phases of the codling moth and on the number of predicted infection days of fire blight. Codling moth (Cydia pomonella) and fire blight (Erwinia amylovora) are two major pest and disease threats to apple, one of the most important commercial and rural crops across Europe. Results for the codling moth indicate a shift in the occurrence and duration of life phases relevant for pest control. In southern Switzerland, a rd generation per season occurs only very rarely under today's climate conditions but is projected to become normal in the 2045-2074 time period. While the potential risk for a rd generation is also significantly increasing in northern Switzerland (for most stations from roughly 1 % on average today to over 60 % in the future for the median climate change signal of the multi-model projections), the actual risk will critically depend on the pace of the adaptation of the codling moth with respect to the critical photoperiod. To control this additional generation, an intensification and prolongation of control measures (e.g., insecticides) will be required, implying an increasing risk of pesticide resistances. For fire blight, the projected changes in infection days are less certain due to uncertainties in the leaf wetness approximation and the simulation of the blooming period. Two compensating effects are projected, warmer temperatures favoring infections are balanced by a temperature-induced advancement of the blooming period, leading to no significant change in the number of infection days under future climate conditions for most stations.
    Full-text · Article · Aug 2011 · Earth System Dynamics Discussions 
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    ABSTRACT: The walnut husk fly, Rhagoletis completa Cresson (Diptera: Tephritidae), has recently invaded Switzerland, Austria, Germany, and France, probably crossing the alpine divide after its initial introduction into Italy. Here, the susceptibility of 36 walnut [Juglans regia L. (Juglandaceae)] cultivars to attack by R. completa was studied in an experimental orchard in Switzerland. Walnut cultivars differed significantly in infestation rates; cultivars that produced large, heavy fruit harboured significantly more larvae than cultivars that produced smaller fruit. Pupal weight was significantly influenced by cultivar, but not by any of the physical properties that we measured. For individual fruit within a cultivar, pupal weight was weakly related to fruit weight and infestation level. Adult longevity was correlated with pupal weight and appeared to be favoured in flies that developed in large-fruit cultivars. The longevities of adults recovered from different cultivars differed significantly. The shortest longevity was recorded for flies recovered from Geisenheim 1049 (39.2 ± 2.80 days) and the longest for flies recovered from Sheinovo (68.8 ± 21.75 days). Differences in diapause length were also highly significant and varied between 167 ± 5.1 (Esterhazy III) and 257.4 ± 8.21 days (Mayette). These results suggest that (1) across and within cultivars, walnut husk flies prefer to infest (i.e., they develop better in) large, heavy fruit, and (2) offspring that develop in large fruit are likely to accrue fitness advantages over the offspring of females using smaller fruit. Our results provide the basis for subsequent studies on resource defence by males, as they enable a prediction of which type of fruit males should defend more vigorously.
    Full-text · Article · Aug 2011 · Entomologia Experimentalis et Applicata
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    M Aluja · L Guillén · J Rull · H Höhn · J Frey · B Graf · J Samietz
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    ABSTRACT: The Walnut Husk Fly, Rhagoletis completa Cresson (Diptera: Tephritidae), is native to North America (Midwestern US and north-eastern Mexico) and has invaded several European countries in the past decades by likely crossing the alpine divide separating most parts of Switzerland from Italy. Here, we determined its current distribution in Switzerland by sampling walnuts (Juglans regia L.) in ecologically and climatically distinct regions along potential invasion corridors. R. completa was found to be firmly established in most low altitude areas of Switzerland where walnuts thrive, but notably not a single parasitoid was recovered from any of the samples. Infested fruit was recovered in 42 of the 71 localities that were surveyed, with mean fruit infestation rate varying greatly among sites. The incidence of R. completa in Switzerland is closely related to meteorological mean spring temperature patterns influencing growing season length, but not to winter temperatures, reflecting survival potential during hibernation. Importantly, areas in which the fly is absent correspond with localities where the mean spring temperatures fall below 7°C. Historical data records show that the natural cold barrier around the Alpine divide in the central Swiss Alps corresponding to such minimal temperatures has shrunk significantly from a width of more than 40 km before 1990 to around 20 km after 2000. We hypothesize on possible invasion/expansion routes along alpine valleys, dwell on distribution patterns in relation to climate, and outline future research needs as the incursion of R. completa into Switzerland; and, more recently, other European countries, such as Germany, Austria, France and Slovenia, represent an example of alien species that settle first in the Mediterranean Basin and from there become invasive by crossing the Alps.
    Full-text · Article · Feb 2011 · Bulletin of entomological research
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    ABSTRACT: In the years 2007-2009, trials on control of codling moth (CM), Cydia pomonella (L.), were carried out in apple orchards of South-East Bulgaria, where the pressure of the pest was very high. Mating disruption with Isomate C plus dispensers was applied in combination with sprays of the virus product Madex®. With a single installation of Isomate C plus dispensers per season + 4 treatments of Madex® at 100 ml per ha against the first and 6 treatments against the second generation, fruit damage at harvest and population density of codling moth were kept at a low level. At the same time fruit damage and population density of the pest, as estimated by the hibernating CM larvae population, was very high in the conventionally treated orchard serving as a reference. Using Isomate C plus dispensers and the baculovirus product Madex® may be a promising alternative to traditional programmes trying to control high initial infestation of codling moth. For Bulgaria, the combined tested strategies of mating disruption and virus control are suggested for control of codling moth in the orchards with CM population density of more than 3 larvae per tree or more than 5% fruit damage in the previous year.
    Full-text · Article · Dec 2010 · Journal of Plant Protection Research
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    ABSTRACT: As a consequence of current and projected climate change in temperate regions of Europe, agricultural pests and diseases are expected to occur more frequently and possibly to extend to previously unaffected regions. Given their economic and ecological relevance, detailed forecasting tools for various pests have been developed, which model the infestation depending on actual weather conditions. Assessing the future risk of pest-related damages therefore requires future weather data at high temporal and spatial resolution. In particular, pest forecast models are often not based on screen temperature and precipitation alone (i.e., the most generally projected climate variables), but might require input variables such as soil temperature, in-canopy net radiation or leaf wetness. Here, we use a stochastic weather and a re-sampling procedure for producing site-specific hourly weather data from regional climate change scenarios for 2050 in Switzerland. The climate change scenarios were derived from multi-model projections and provide probabilistic information on future regional changes in temperature and precipitation. Hourly temperature, precipitation and radiation data were produced by first generating daily weather data for these climate scenarios and then using a nearest neighbor re-sampling approach for creating realistic diurnal cycles. These hourly weather time series were then used for modeling important phases in the lifecycle of codling moth, the major insect pest in apple orchards worldwide. First results indicate a shift in the occurrence and duration of phases relevant for pest disease control for projected as compared to current climate (e.g. the flight of the codling moth starts about ten days earlier in future climate), continuing an already observed trend towards more favorable conditions for this insect during the last 20 years.
    No preview · Article · Sep 2010
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    ABSTRACT: Apple crop protection mainly relies on pesticides although several alternative pest management strategies being available. This is largely caused by the problem that multiple environmental and economic aspects are to consider simultaneously, hiding if one strategy is more sustainable than another. In our study we investigated the elements that need to be considered in order to reach transparency upon the overall result of the sustainability assessment. We present a system description tool created specially for data collection required by life cycle assessment, environmental risk assessment and full cost calculations. Using the various results from these assessments as qualitative attributes we designed a multicriteria tool that allows us to aggregate sustainability attributes over five levels to an overall sustainability rating. An example, assessing different crop protection systems of apple production, demonstrates the transparency of this method. We conclude that rating scales and decision rules might substantially influence the overall sustainability rating. Therefore, the definition of rating scales and decision rules should be carefully set and discussed among the research teams. In our case experts have participated from five European countries being partner of the EU-FP6 project ENDURE.
    Full-text · Article · Aug 2010
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    ABSTRACT: In most central European grasshopper populations, matings are very rarely observed. For five species we here quantify how frequently matings are observed. In total, only 78 matings were recorded over a period of 1100 observation hours in five acridid grasshopper species. We formally define the term mating activity (MA) as the proportion of individuals mating at a given time. MA in Oedipoda germanica, but not Euthystira brachyptera, took place preferentially around noon. In Stenobothrus lineatus, Gomphocerippus rufus and Chorthippus parallelus, matings possibly extended into the night. We also found evidence for a seasonal decrease in MA in S. lineatus and G. rufus but not in C. parallelus and O. germanica. Mating females were younger than the population average in S. lineatus, G. rufus and O. germanica. A review of the literature revealed a seasonal decline in MA in other species as well. Diel mating peaks are not very distinct, though some species seem to mate exclusively at night, some have peaks during the hottest parts of the day, and a third group seems to avoid the hot midday periods.
    Full-text · Article · Jan 2009 · Journal of Orthoptera Research

Publication Stats

648 Citations
64.11 Total Impact Points

Institutions

  • 1999-2012
    • Universitätsklinikum Jena
      Jena, Thuringia, Germany
  • 2002-2009
    • ETH Zurich
      Zürich, Zurich, Switzerland
  • 2008
    • Karl-Franzens-Universität Graz
      • Institute of Zoology
      Gratz, Styria, Austria
  • 1997-2005
    • Friedrich-Schiller-University Jena
      • Institute of Ecology
      Jena, Thuringia, Germany
  • 2004
    • Eawag: Das Wasserforschungs-Institut des ETH-Bereichs
      Duebendorf, Zurich, Switzerland