Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Webinar Slecht nieuws voor de Duizendknoop: praktijkkennisnetwerk van start!
    Lommen, Suzanne ; Dijk, C.J. van - \ 2020
    Vereniging Stadswerk Nederland ism SDU
    De Aziatische duizendknoop staat wereldwijd op de agenda. Deze lastig te bestrijden invasieve exoot kan andere planten verdringen, voor schade zorgen aan wegen, bruggen, glooiingen en gebouwen en vormt een toenemend probleem voor overheden, bedrijven en particulieren.
    Potato Yield and Yield Components as Affected by Positive Selection During Several Generations of Seed Multiplication in Southwestern Uganda
    Priegnitz, Uta ; Lommen, Willemien J.M. ; Vlugt, René A.A. van der; Struik, Paul C. - \ 2020
    Potato Research (2020). - ISSN 0014-3065
    Multi-seasonal trials - Positive selection - Seed degeneration - Seed potatoes - Seed regeneration - Uganda - Yield increase

    Potato (Solanum tuberosum L.) is an important crop in Uganda but production is low. There is not a well-functioning official seed system and farmers use potato tubers from a previous harvest as seed. This study investigated how effectively the seed technology positive selection enhanced yield and underlying crop characteristics across multiple seasons, compared to the farmers’ selection method. Positive selection is selecting healthy plants during crop growth for harvesting seed potato tubers to be planted in the next season. Farmers’ selection involves selection of seed tubers from the bulk of the ware potato harvest. Positive selection was compared to farmers’ seed selection for up to three seasons in three field trials in different locations in southwestern Uganda using seed lots from different origins. Across all experiments, seasons and seed lots, yields were higher under positive selection than under farmers’ selection. The average yield increase resulting from positive selection was 12%, but yield increases were variable, ranging from − 5.7% to + 36.9%, and in the individual experiments often not significant. These yield increases were due to higher yields per plant, and mostly higher weights per tuber, whereas the numbers of tubers per plant were not significantly different. Experimentation and yield assessment were hampered by a varying number of plants that could not be harvested because plants had to be rogued from the experimental plots because of bacterial wilt (more frequent under farmers’ selection than under positive selection), plants disappeared from the experimental field and sometimes plants did not emerge. Nevertheless, adoption of positive selection should be encouraged due to a higher production and less virus infection of seed tubers in positive selected plants, resulting in a lower degeneration rate of potato seed tubers.

    Analytical strategies in non-target measurement of pesticide biomarkers
    Mol, J.G.J. ; Nijssen, Rosalie ; Lommen, A. ; Tricht, E.F. van; Top, H.J. van den; Dam, R.C.J. van; Zomer, P. ; Blokland, M.H. - \ 2019
    Assessment of exposure to pesticides: residues in 24h duplicate diets versus their biomarkers in 24h urine
    Nijssen, Rosalie ; Lommen, A. ; Top, H.J. van den; Dam, R.C.J. van; Tienstra, M. ; Blokland, M.H. ; Wegh, R.S. ; Tricht, E.F. van; Mol, J.G.J. - \ 2019
    Genetics and selective breeding of variation in wing truncation in a flightless aphid control agent
    Lommen, Suzanne T.E. ; Koops, Kees G. ; Cornelder, Bardo A. ; Jong, Peter W. de; Brakefield, Paul M. - \ 2019
    Entomologia Experimentalis et Applicata 167 (2019)7. - ISSN 0013-8703 - p. 636 - 645.
    Adalia bipunctata - artificial selection - augmentative pest control - biological control - Coccinellidae - Coleoptera - cryptic genetic variation - gene-by-environment interaction - ladybird - modifier genes - predator - winglessness

    Augmentative biological control by predaceous ladybird beetles can be improved by using flightless morphs, which have longer residence times on the host plants. The two-spot ladybird beetle, Adalia bipunctata (L.) (Coleoptera: Coccinellidae), is used for the biological control of aphids in greenhouses and on urban trees. Flightlessness due to truncated wings occurs at very low frequency in some natural populations of A. bipunctata. Pure-breeding strains of this 'wingless' genotype of A. bipunctata can easily be obtained in the laboratory. Such strains have not been commercialized yet due to concerns about their reduced fitness compared to wild-type strains, which renders mass production more expensive. Wingless strains exhibit, however, wide intra-population phenotypic variation in the extent of wing truncation which is related to fitness traits. We here use classical quantitative genetic techniques to study the heritability and genetic architecture of variation in wing truncation in a wingless strain of A. bipunctata. Split-families reared at one of two temperatures revealed strong family-by-temperature interaction: heritability was estimated as 0.64 ± 0.09 at 19 °C and 0.29 ± 0.06 at 29 °C. Artificial selection in opposite directions at 21 °C demonstrated that the degree of wing truncation can be altered within a few generations resulting in wingless phenotypes without any wing tissue (realized h2 = 0.72), as well as those with minimal truncations (realized h2 = 0.61) in two replicates. The latter lines produced more than twice as many individuals. This indicates that selective breeding of wing truncation may be exploited to improve mass rearing of flightless strains of A. bipunctata for commercial biological control. Our work illustrates that cryptic variation can also be a source for the selective breeding of natural enemies.

    Automated Gas and Liquid Chromatography Retention Time Modelling and Prediction Using Open-Access Molecular Database Structures and Quantitative Structure-Chromatography Retention Relationships
    Lommen, A. ; Horvatovich, Peter L. ; Vonaparti, Ariadni ; Al-Maadheed, Muhammad ; Nielen, M.W.F. ; Georgakopoulos, Costas - \ 2019
    Journal of chromatography 33 (2019). - ISSN 0378-4355 - p. 6 - 14.
    Rapid Retrospective Assessment of Exposure of Cattle to Pesticides, Growth Promotors, Antibiotics by Use of In-House Developed Software Tools
    Blokland, Marco ; Lommen, Arjen ; Wegh, Robin ; Tricht, Frederike van; Mol, Hans ; Nielen, Michel - \ 2019
    Pesticides biomarkers in 24h urine versus pesticides in duplicate diets using suspect screening and target analysis
    Mol, Hans ; Nijssen, Rosalie ; Lommen, Arjen ; Bot, Carmen ; Top, Hester van den; Tricht, Frederike van; Dam, Ruud van; Zomer, Paul ; Blokland, Marco - \ 2019
    Fiche synthétique présentant les pratiques agronomiques de production d’ananas destinés à la consommation sous forme de fruit et à la transformation en jus d’ananas
    Djido, U. ; Fassinou Hotegni, V.N. ; Kpènavoun Chogou, S. ; Lommen, W.J.M. ; Hounhouigan, M.H. ; F., Chadaré ; Hounhouigan, J.D. ; Achigan-Dako, E.G. ; Struik, P.C. - \ 2019
    - 12 p.
    Understanding seed potato selection practices in Uganda
    Priegnitz, Uta - \ 2019
    Wageningen University. Promotor(en): P.C. Struik; R.A.A. van der Vlugt, co-promotor(en): W.J.M. Lommen; S. Onakuse. - Wageningen : Wageningen University - ISBN 9789463951982 - 214

    Potato (Solanum tuberosum L.) is an important crop for food security and cash income for  smallholder farmers in Uganda. However, the national mean potato yield has been in decline to less than 5 Mg ha-1 in 2016. Low productivity of potato might be associated with poor and diverse adoption of innovative crop management practices. Smallholder farmers in Uganda commonly use seed potato tubers from the informal sector, especially by seed recycling over several generations. Therefore, seed tubers are highly degenerated with viruses and other diseases, resulting in poor yield and quality of the produce. Over one cycle of multiplication, the degeneration management by positive seed selection was found to be efficient in reducing virus diseases compared with the farmers’ method of selection. The aim of this thesis was to provide novel information regarding understanding positive seed selection by investigating it across multiple cycles of multiplication with an interdisciplinary approach.

    To identify potato farms that are homogeneous in uptake of innovations (use of fertilizer, organic input, fungicides, pesticides, seed selection methods, seed renewal by using quality declared seed, and sole cropping), a farm typology was used and socio-economic characteristics, access to agricultural extension services, memberships of farmers’ groups, yield levels of potato and economic return rates were assessed. A farm household survey (n=270) was carried out and principal component analysis and cluster analysis were used to identify types of farms differing in adoption of innovations. Four farm types were identified that demonstrated significant differences in uptake of innovation practices; these differences in uptake were associated with small but significant differences in yield and further in land ownership, availability of labourers and cash, economic return, and access to knowledge. The farm type with relatively high frequencies of using organic input, fungicide input, pesticide input, seed plot technology or positive selection, quality declared seed and sole cropping achieved highest potato productivity; the farm type with relatively frequent use of fungicide input and no use of pesticides was associated with the lowest potato yield.

    To assess to what extent positive selection over several seasons can reduce incidences of six different viruses in seed lots of different starting quality, multi-seasonal trials were carried out in three locations, with five seed lots from four sources and three cultivars. Detection of viruses was based on DAS-ELISA and Luminex xMAP technology. Results showed fluctuations in some viruses over seasons, with lower Potato leafroll virus (PLRV) and Potato virus X (PVX) incidences in lots from positive selection compared with lots from farmers’ selection. Some seed lots were initially highly infected with Potato virus S (PVS) and Potato virus M (PVM) and showed no reduction in virus incidence through positive selection. In general, little infection with Potato virus Y (PVY) and Potato virus A (PVA) was found.

    To investigate how effectively positive selection enhances yield and underlying crop characteristics, positive selection was compared with farmers’ seed selection for up to three seasons in three field trials at different locations. Across all experiments, seasons and seed lots, yields were higher under positive selection than under farmers’ selection. The average yield increase resulting from positive selection was 12%, but yield increases were variable, ranging from –5.7% to +36.9%, and in the individual experiments often not significant. These yield increases were associated with higher yields per plant, and mostly higher weights per tuber, whereas the numbers of tubers per plant were not significantly different. Experimentation and yield assessment were hampered by a varying number of plants that could not be harvested because plants had to be rogued from the experimental plots because of bacterial wilt (more frequent under farmers’ selection than under positive selection), plants disappeared from the experimental field and sometimes plants did not emerge.

    To evaluate costs and benefits of positive selection in order to assess its feasibility and affordability, data from the smallholder farms in the four farm types were used for an economic analysis. It showed that farms that already adopted positive selection, invested on average 1.2 extra days (i.e. 2.7 extra labourer days) per acre in positive selection, with an average of 4.0% extra labour costs. A scenario study among the non-adopters of positive selection, assuming a 10% extra yield by carrying out positive selection, showed that a marginal rate of return of adopting positive selection of far above 100% was achieved in every farm type. Gross and net benefit varied because of different yield increases and different selling prices of potatoes in the different farm types, indicating that some farm households benefitted more than others.

    The present study shows that positive selection does fit in the current seed system for smallholder farmers and has the capacity to increase yield and reduce viruses with visible symptoms compared to farmers’ selection. Positive selection being part of the informal and integrated seed sector will help improve seed quality and seed health in farmers’ networks.

    A Farm Typology for Adoption of Innovations in Potato Production in Southwestern Uganda
    Priegnitz, Uta ; Lommen, Willemien J.M. ; Onakuse, Stephen ; Struik, Paul C. - \ 2019
    Frontiers in Sustainable Food Systems 3 (2019). - ISSN 2571-581X - 15 p.
    In Uganda, low productivity of potato might be associated with poor and diverse adoption of innovative crop management practices. This paper aims to identify the potato farm typologies in southwestern Uganda, i.e., collections of farms that are homogeneous in uptake of innovations (use of fertilizer, organic input, fungicides, pesticides, seed selection methods, seed refreshment by using quality declared seed, and sole cropping), and to analyse these typologies based on socio-economic characteristics, access to agricultural extension services, memberships of farmers' groups, yield levels of potato and return rates. A farm household survey (n = 270) was carried out and principal component analysis and cluster analysis were used to identify types of farms differing in adoption of innovations. Four farm types were identified that demonstrated significant differences in uptake of innovation practices; despite the small differences in yield among farm types, differences in uptake were associated with significant differences in the yield and further in land ownership, availability of laborers and cash, economical return, and access to knowledge. The farm type with relatively high frequencies of using organic input, fungicide input, pesticide input, seed plot technology or positive selection, quality declared seed, and sole cropping achieved highest potato productivity; the farm type with relatively frequent use of fungicide input and no use of pesticides was associated with the lowest potato yield. The findings emphasize associations between innovation uptake and farm characteristics. Opportunities for improvement through extension services and shared knowledge can achieve wider adoption, enhance potato productivity and increase income for smallholder farmers.
    Supplementary Material to: Automated Gas and Liquid Chromatography Retention Time Modelling and Prediction Using Open-Access Molecular Database Structures and Quantitative Structure-Chromatography Retention Relationships
    Lommen, A. ; Horvatovich, Peter L. ; Vonaparti, Ariadni ; Al-Maadheed, Muhammad ; Nielen, M.W.F. ; Georgakopoulos, Costas - \ 2019
    Wageningen University & Research
    Ultra-fast retroactive processing of liquid chromatography high-resolution full-scan Orbitrap mass spectrometry data in anti-doping screening of human urine
    Lommen, Arjen ; Elaradi, Abdurzag ; Vonaparti, Ariadni ; Blokland, Marco ; Nielen, Michel W. ; Saad, Khadija Ali ; Abushreeda, Wadha Masoud ; Horvatovich, Peter ; Al-Muraikhi, Amal Essa ; Al-Maadheed, Mohammed ; Georgakopoulos, Costas - \ 2019
    Rapid Communications in Mass Spectrometry 33 (2019)20. - ISSN 0951-4198 - p. 1578 - 1588.

    Rationale: Retroactive analysis of previously tested urine samples has become an important sports anti-doping tool. Retroactive reprocessing of old data files acquired from a generic screening procedure can reveal detection of initially unknown substances, like illegal drugs and newly identified metabolites. Methods: To be able to efficiently search through hundreds to thousands of liquid chromatography high-resolution full-scan Orbitrap mass spectrometry data files of anti-doping samples, a combination of MetAlign and HR_MS_Search software has been developed. MetAlign reduced the data size ca 100-fold making possible local storage of a massive volume of data. Results: The newly developed HR_MS_Search module can search through the reduced data files for new compounds (mass or isotope pattern) defined by mass windows and retention time windows. A search for 33 analytes in 940 reduced data files lasted 10 s. The output of the automatic search was compared to the standard manual routine evaluation. The results of searching were evaluated in terms of false negatives and false positives. The newly banned b2-agonist higenamine and its metabolite coclaurine were successfully searched in reduced data files originating from a testing period for which these substances were not banned, as an example of retroactive analysis. Conclusions: The freeware MetAlign software and its automatic searching module HR_MS_Search facilitated the retroactive reprocessing of reduced full-scan high-resolution liquid chromatography/mass spectrometry screening data files and created a new tool in anti-doping laboratories' network.

    Impact of Positive Selection on Incidence of Different Viruses During Multiple Generations of Potato Seed Tubers in Uganda
    Priegnitz, Uta ; Lommen, Willemien J.M. ; Vlugt, René A.A. van der; Struik, Paul C. - \ 2019
    Potato Research 62 (2019)1. - ISSN 0014-3065 - p. 1 - 30.
    Multi-seasonal trials - Positive selection - Seed degeneration - Seed potatoes - Seed regeneration - Uganda - Viruses

    Smallholder farmers in Uganda commonly use seed potato tubers from the informal sector, especially by seed recycling over several generations. Therefore, seed tubers are highly degenerated with viruses and other pathogens, resulting in poor yield and quality of the produce. Over one cycle of multiplication, degeneration management by positive seed selection was found to be efficient in reducing virus diseases compared with the farmers’ method of selection. The objective of this study was to assess to what extent positive selection over several seasons can reduce six different virus incidences in seed lots of different starting quality in southwestern Uganda. Multi-seasonal trials were carried out in three locations, with five seed lots from four sources and three cultivars. Detection of viruses was based on DAS-ELISA and Luminex xMAP technology. Analysis was carried out with analysis of variance (ANOVA) on angular-transformed percentages of virus incidence. Results showed fluctuations in some viruses over seasons with lower Potato leafroll virus (PLRV) and Potato virus X (PVX) incidences in lots from positive selection compared with lots from farmers’ selection. In contrast, some seed lots were initially highly infected with Potato virus S (PVS) and Potato virus M (PVM) and showed no reduction in virus incidence through positive selection. In general, little infection with Potato virus Y (PVY) and Potato virus A (PVA) was found. Based on these results, it is recommended that smallholder farmers are trained in positive selection to opt for less virus-infected plants and tubers, thus increasing potato production.

    Omics analyses of potato plant materials using an improved one-class classification tool to identify aberrant compositional profiles in risk assessment procedures
    Kok, Esther ; Dijk, Jeroen van; Voorhuijzen, Marleen ; Staats, Martijn ; Slot, Martijn ; Lommen, Arjen ; Venema, Dini ; Pla, Maria ; Corujo, Maria ; Barros, Eugenia ; Hutten, Ronald ; Jansen, Jeroen ; Voet, Hilko van der - \ 2019
    Food Chemistry 292 (2019). - ISSN 0308-8146 - p. 350 - 358.
    Compositional analysis - Genetically modified organism - GMO - Omics profiling - Risk assessment

    The objective of this study was to quantitatively assess potato omics profiles of new varieties for meaningful differences from analogous profiles of commercial varieties through the SIMCA one-class classification model. Analytical profiles of nine commercial potato varieties, eleven experimental potato varieties, one GM potato variety that had acquired Phytophtora resistance based on a single insert with potato-derived DNA sequences, and its non-GM commercial counterpart were generated. The ten conventional varieties were used to construct the one-class model. Omics profiles from experimental non-GM and GM varieties were assessed using the one-class SIMCA models. No potential unintended effects were identified in the case of the GM variety. The model showed that varieties that were genetically more distant from the commercial varieties were recognized as aberrant, highlighting its potential in determining whether additional evaluation is required for the risk assessment of materials produced from any breeding technique, including genetic modification.

    Use of omics analytical methods in the study of genetically modified maize varieties tested in 90 days feeding trials
    Corujo, Maria ; Pla, Maria ; Dijk, Jeroen van; Voorhuijzen, Marleen ; Staats, Martijn ; Slot, Martijn ; Lommen, Arjen ; Barros, Eugenia ; Nadal, Anna ; Puigdomènech, Pere ; Paz, José Luís La ; Voet, Hilko van der; Kok, Esther - \ 2019
    Food Chemistry 292 (2019). - ISSN 0308-8146 - p. 359 - 371.
    GMO (genetically modified organism) - Metabolomics - One-class model - Proteomics - Risk assessment - Transcriptomics

    Genetically modified (GM) maize and their non-modified counterparts were compared using MON810 varieties, the only GMO event cultivated in Europe. The differences in grain samples were analysed by omics profiles, including transcriptomics, proteomics and metabolomics. Other cultivated maize varieties were analysed as a reference for the variability that will exist between cultivated varieties. The observed differences between modified and non-modified maize varieties do not exceed typical differences between non-modified varieties. The use of these advanced analytical approaches to analyse novel plant materials as compared to the results from animal feeding trials with whole foods is assessed. No indications were observed for changes in the GM varieties that warrant further investigations. Furthermore, it was shown that such indications will be obtained if maize samples of inferior quality are analysed similarly. Omics data provide detailed analytical information of the plant material, which facilitates a risk assessment procedure of new (GM) plant varieties.

    Comparison of gas chromatography/quadrupole time-of-flight and quadrupole Orbitrap mass spectrometry in anti-doping analysis : I. Detection of anabolic-androgenic steroids
    Abushareeda, Wadha ; Tienstra, Marc ; Lommen, Arjen ; Blokland, Marco ; Sterk, Saskia ; Kraiem, Suhail ; Horvatovich, Peter ; Nielen, Michel ; Al-Maadheed, Muhammad ; Georgakopoulos, Costas - \ 2018
    Rapid Communications in Mass Spectrometry 32 (2018)23. - ISSN 0951-4198 - p. 2055 - 2064.

    Rationale: The World Anti-Doping Agency (WADA) encourages drug-testing laboratories to develop screening methods that can detect as many doping substances as possible in urine. The use of full-scan high-resolution acquisition (FS/HR) with gas chromatography/mass spectrometry (GC/MS) for the detection of known and unknown trimethylsilyl (TMS) derivatives of anabolic-androgenic steroids (AAS) provides anti-doping testing bodies with a new analytical tool. Methods: The AAS were extracted from urine samples by generic liquid–liquid extraction, after enzymatic hydrolysis, and TMS derivatization. The extracted urine was analyzed by GC/Q-TOF and GC/Q-Orbitrap to compare the performance of the two instrument types for the detection of 46 AAS in human urine. The quantitation of endogenous anabolic steroids and the ability of the two analytical platforms to comply with the requirements for testing as part of the WADA Athlete Biological Passport (ABP) were also assessed. Results: The data presented show that the analytical performance for both instruments complies with the WADA specifications. The limits of detection (LODs) for both instruments are well below the WADA 50% Minimum Required Performance Levels. The mass errors in the current study for the GC/Q-Orbitrap platform are lower than those obtained for the GC/Q-TOF instrument. Conclusions: The data presented herein proved that both molecular profiling platforms can be used for antidoping screening. The mass accuracies are excellent in both instruments; however, the GC/Q-Orbitrap performs better as it provides higher resolution than the GC/Q-TOF platform.

    Cross-fertilizing weed science and plant invasion science to improve efficient management: A European challenge
    Müller-Schärer, H. ; Sun, Y. ; Chauvel, B. ; Karrer, G. ; Kazinczi, G. ; Kudsk, P. ; Oude Lansink, A.G.J.M. ; Schaffner, U. ; Skjoth, C.A. ; Smith, M. ; Vurro, M. ; Weger, L.A. De; Lommen, S.T.E. - \ 2018
    Basic and Applied Ecology 33 (2018). - ISSN 1439-1791 - p. 1 - 13.
    Both weed science and plant invasion science deal with noxious plants. Yet, they have historically developed as two distinct
    research areas in Europe, with different target species, approaches and management aims, as well as with diverging institutions
    and researchers involved. We argue that the strengths of these two disciplines can be highly complementary in implementing
    management strategies and outline how synergies were created in an international, multidisciplinary project to develop efficient
    and sustainable management of common ragweed, Ambrosia artemisiifolia. Because this species has severe impacts on human
    health and is also a crop weed in large parts of Europe, common ragweed is one of the economically most important plant
    invaders in Europe. Our multidisciplinary approach combining expertise from weed science and plant invasion science allowed
    us (i) to develop a comprehensive plant demographic model to evaluate and compare management tools, such as optimal cutting
    regimes and biological control for different regions and habitat types, and (ii) to assess benefits and risks of biological control.
    It further (iii) showed ways to reconcile different stakeholder interests and management objectives (health versus crop yield),
    and (iv) led to an economic model to assess invader impact across actors and domains, and effectiveness of control measures.
    (v) It also led to design and implement management strategies in collaboration with the various stakeholder groups affected by
    noxious weeds, created training opportunities for early stage researchers in the sustainable management of noxious plants, and
    actively promoted improved decision making regarding the use of exotic biocontrol agents at the national and European level.
    We critically discuss our achievements and limitations, and list and discuss other potential Old World (Afro-Eurasian) target
    High resolution full scan liquid chromatography mass spectrometry comprehensive screening in sports antidoping urine analysis
    Abushareeda, Wadha ; Vonaparti, Ariadni ; Saad, Khadija Al ; Almansoori, Moneera ; Meloug, Mbarka ; Saleh, Amal ; Aguilera, Rodrigo ; Angelis, Yiannis ; Horvatovich, Peter L. ; Lommen, Arjen ; Alsayrafi, Mohammed ; Georgakopoulos, Costas - \ 2018
    Journal of Pharmaceutical and Biomedical Analysis 151 (2018). - ISSN 0731-7085 - p. 10 - 24.
    Full scan high-resolution - Human urine - Liquid chromatography - Mass spectrometry - Small molecule prohibited substances - Sulfo-conjugate steroids
    The aim of this paper is to present the development and validation of a high-resolution full scan (HR-FS) electrospray ionization (ESI) liquid chromatography coupled to quadrupole Orbitrap mass spectrometer (LC/Q/Orbitrap MS) platform for the screening of prohibited substances in human urine according to World Antidoping Agency (WADA) requirements. The method was also validated for quantitative analysis of six endogenous steroids (epitestosterone, testosterone, 5α-dihydrotestosterone, dehydroepiandrosterone, androsterone and etiocholanolone) in their intact sulfates form. The sample preparation comprised a combination of a hydrolyzed urine liquid–liquid extraction and the dilute & shoot addition of original urine in the extracted aliquot. The HR-FS MS acquisition mode with Polarity Switching was applied in combination of the Quadrupole-Orbitrap mass filter. The HR-FS acquisition of analytical signal, for known and unknown small molecules, allows the inclusion of all analytes detectable with LC–MS for antidoping investigations to identify the use of known or novel prohibited substances and metabolites after electronic data files’ reprocessing. The method has been validated to be fit-for-purpose for the antidoping analysis.
    Population growth rate of dry bulb mite, Aceria tulipae (Acariformes : Eriophyidae), on agriculturally important plants and implications for its taxonomic status
    Kiedrowicz, Agnieszka ; Rector, Brian G. ; Lommen, Suzanne ; Kuczyński, Lechosław ; Szydło, Wiktoria ; Skoracka, Anna - \ 2017
    Experimental and Applied Acarology 73 (2017)1. - ISSN 0168-8162 - p. 1 - 10.
    Cryptic species - Garlic pest - Host adaptation - Host range - Host specificity - Laboratory rearing
    Dry bulb mite (DBM), Aceria tulipae, is an economically important mite with a worldwide distribution and a broad host range. As a generalist, it is the most important eriophyoid mite attacking bulbous plants such as garlic, onion and tulip. To date, DBM has been recorded on host plants belonging to the families Liliaceae, Amaryllidaceae, Melanthiaceae and Asparagaceae. However, a precise understanding of DBM host range is lacking as it is largely based on casual records of mites on plants, some of which may include accidental hosts. Moreover, the possible existence of cryptic species has not been considered. In this study the hypothesis that DBM may be a complex of distinct genetic lineages or cryptic species was tested by comparing the common barcode sequence marker mtDNA COI of specimens from several populations originating from the Netherlands and Poland. The population growth rate of DBM on seven agriculturally important plant species and on various parts of the garlic plant was also experimentally assessed in the laboratory. The results did not support the first hypothesis, and indicated that DBM populations originating from Poland and the Netherlands shared essentially the same genome. In addition, they indicated that DBM reached the highest population growth rate on leek and also displayed high growth rates on garlic, chive and red onion, whereas white onion and wheat were not colonized by the mites. Answering the question of whether DBM is a single polyphagous species rather than a complex of cryptic lineages is of particular importance since the misidentification of pests may lead to ineffective control strategies. Moreover, improved knowledge of DBM host range is essential for assessing risk to crops.
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