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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Gebruik van groene middelen : Inventarisatie laanboomkwekerij
Sluis, B.J. van der; Kuik, A.J. van; Baltissen, A.H.M.C. - \ 2016
Wageningen : Wageningen Plant Research, Bloembollen, Boomkwekerij & Fruit - 22 p.
bos- en haagplantsoen - straatbomen - aantrekkelijke bomen - gelderland - gewasbescherming - geïntegreerde plagenbestrijding - biologische bestrijding - natuurlijke producten - bladvoeding - natuurlijke vijanden - organismen ingezet bij biologische bestrijding - woody nursery stock - street trees - amenity trees - plant protection - integrated pest management - biological control - natural products - foliar nutrition - natural enemies - biological control agents
In de laanboomteelt in de regio Opheusden wordt al jarenlang gewerkt aan verduurzaming van de teeltmethoden. Het verantwoord toepassen van gewasbeschermingsmiddelen is daarvan een belangrijk onderdeel. Door strengere regelgeving wordt het chemische middelenpakket steeds verder beperkt en komen boomkwekers in toenemende mate voor knelpunten te staan. Uit oriënterende gesprekken in de regio blijkt dat een deel van de boomkwekerijbedrijven zich inmiddels toelegt op het gebruik van groene middelen om zo de afhankelijkheid van chemische middelen te verkleinen. Volgens de definitie van het Ctgb zijn dit gewasbeschermingsmiddelen van natuurlijke oorsprong (planten, dieren, microorganismen) met een laag risico voor mens, dier, milieu en niet-doelorganismen. In dit project wordt geïnventariseerd wat de mate van gebruik is van groene middelen door laanboomkwekers in de regio Rivierenland én wat hun ervaringen zijn met deze middelen. De uitkomst kan de sector in de regio benutten om de kennisuitwisseling voor duurzaam telen te bevorderen, zowel tussen kwekers als naar de burgers.
Plant responses to multiple herbivory : phenotypic changes and their ecological consequences
Li, Yehua - \ 2016
Wageningen University. Promotor(en): Marcel Dicke, co-promotor(en): Rieta Gols. - Wageningen : Wageningen University - ISBN 9789462578043 - 165
brassica oleracea - brevicoryne brassicae - aphidoidea - caterpillars - insect pests - pest resistance - defence mechanisms - phenotypes - insect plant relations - parasitoids - natural enemies - herbivore induced plant volatiles - plant-herbivore interactions - genetic variation - rupsen - insectenplagen - plaagresistentie - verdedigingsmechanismen - fenotypen - insect-plant relaties - parasitoïden - natuurlijke vijanden - herbivoor-geinduceerde plantengeuren - plant-herbivoor relaties - genetische variatie

This thesis explores whether aphid-infestation interferes with the plant response to chewing herbivores and whether this impacts performance and behaviour of individual chewing insect herbivores and their natural enemies, as well as the entire insect community. I investigated this using three wild cabbage populations (Brassica oleracea) that are known to differ in inducible secondary chemistry, to reveal whether patterns were consistent.

A literature review on recent developments in the field of plant interactions with multiple herbivores (Chapter 2) addressed how plant traits mediate interactions with various species of the associated insect community and their dynamics. In addition, the mechanisms underlying phenotypic changes in response to different herbivores were discussed from the expression of defence-related genes, phytohormones and secondary metabolites in plants to their effects on the performance and behaviour of individual insects as well as the entire insect community. In Chapter 3, I investigated the effects of early-season infestation by the aphid Brevicoryne brassicae on the composition and dynamics of the entire insect community throughout the season in a garden experiment replicated in two consecutive years. Aphid infestation in the early season only affected a subset of the community, i.e. the natural enemies of aphids, but not the chewing herbivores and their natural enemies. Moreover, the effects were only significant in the first half (June & July), but waned in the second half of the season (August & September). The effect of aphid infestation on the community of natural enemies also varied among the cabbage populations. Chapter 4 investigated the effects of aphid infestation on plant direct defences against chewing herbivores in laboratory experiments by comparing the performance of chewing herbivores and their parasitoids on aphid-infested and aphid-free plants. The performance of the specialist herbivore Plutella xylostella and its parasitoid Diadegma semiclausum was better on plants infested with aphids than on aphid-free plants, whereas the performance of the generalist herbivore Mamestra brassicae and its parasitoid Microplitis mediator was not affected by aphid infestation. These results suggest that aphid induced changes in plant traits may differentially affect the performance of leaf-chewing herbivore species attacking the same host plant, and also varied among the cabbage populations. Chapter 5 examined the effects of B. brassicae aphid infestation on plant indirect defences against chewing herbivores. In a two-choice olfactometer bioassay, preference behaviour for volatiles emitted by plants infested with hosts alone and those emitted by plants infested with aphids and hosts was compared for D. semiclausum and M mediator, larval endoparasitoids of caterpillars of P. xylostella and M. brassicae, respectively. In addition, the headspace volatiles emitted by host-infested and dually-infested plants were collected and analyzed. Co-infestation with aphids differentially affected volatile-mediated foraging behaviour of the two parasitoid species in an infestation period-dependent manner. Diadegma semiclausum preferred dually infested plants over host-infested plants when aphids infested the plants for a short time period, i.e. 7 days, but the volatile preference of D. semiclausum was reversed when aphid infestation was extended to 14 days. In contrast, M. mediator consistently preferred volatiles emitted by the dually-infested plants over those emitted by host-infested plants. The patterns of preference behaviour of the two wasp species were consistent across the three cabbage populations. Interestingly, the emission rate of most volatile compounds was reduced in plants dually-infested with caterpillars and aphids compared to singly-infested with caterpillars. This study showed that aphid infestation increased plant indirect defences against caterpillars, but depended on the aphid infestation period and specific caterpillar-parasitoid association. We hypothesized a negative interference of aphid infestation on plant defences against chewing herbivores based on previously reported SA-JA antagonism. In Chapter 6, we assessed the activation of SA and JA signaling pathways in plants infested by both aphids (B. brassicae) and various caterpillar species (P. xylostella, M. brassicae and Pieris brassicae) in different time sequences by quantifying transcription levels of the SA- and JA-responsive marker genes, PR-1 and LOX respectively. The results did not provide support for SA-JA antagonism. Compared to single infestation with each of the herbivore species, dual infestation with aphid and caterpillars had no interactive effects on the transcription levels of the SA- and JA-responsive maker genes, regardless of the temporal sequence of aphid and caterpillar attack, or the identity of the attacking caterpillar species.

The findings of this thesis contribute to our understanding of plant responses to herbivory by insect species belonging to different feeding guilds and their ecological effects on other associated community members. Aphid infestation may interfere with plant direct and indirect defences against leaf-chewing herbivores at the individual species level, but the effects are species-specific and also depend on the infestation period of aphids. Early-season aphid infestation may further affect the composition of the insect community, but the effect is smaller influencing only a subset of the community compared to early infestation by chewing herbivores. The molecular mechanism underlying plant responses to both phloem-feeding and leaf-chewing herbivores are complex and require the investigation of a range of genes involved in JA- and SA-mediated defence signal transduction. Plant interact with multiple herbivores at different levels of biological organization ranging from the subcellular level to the individual and the community level, and an integrated multidisciplinary approach is required to investigate plant-insect interactions.

Adapting greenhouse climate for enhanced biocontrol and better performance of plant protection products
Vänninen, I. ; Meijer, R.J.M. - \ 2016
BioGreenhouse (Fact sheet BioGreenhouse 12) - 2 p.
horticulture - greenhouse horticulture - plant protection - natural enemies - pesticides - environmental temperature - humidity - lighting - carbon dioxide - plant health - organic farming - tuinbouw - glastuinbouw - gewasbescherming - natuurlijke vijanden - pesticiden - omgevingstemperatuur - vochtigheid - verlichting - kooldioxide - plantgezondheid - biologische landbouw
In greenhouse crop production, climatic parameters are often manipulated to optimize plant growth. Greenhouse climate has profound influences also on pests and their natural enemies used for biocontrol. The responses of arthropod pests, plant disease agents and natural enemies to constant temperatures and humidity are relatively well known, but many pertinent questions remain unsolved for pest and natural enemy biology and behaviour in conditions created by the newest greenhouse climate technologies and approaches. Greenhouse climate can be optimized also to benefit natural enemies and to work against pests and plant diseases, but we know less how to make this happen than we know how to manipulate plant growth through temperature, humidity, CO2 and light conditions.
Conservation of predaceous Coccinellidae species in greenhouse ecosystems
Papanikolaou, N.E. ; Milonas, P.G. ; Meijer, R.J.M. - \ 2016
BioGreenhouse (Fact sheet BioGreenhouse 7) - 2 p.
organic farming - horticulture - greenhouse horticulture - plant health - natural enemies - habitats - coccinellidae - agroecosystems - biological control - pesticides - biologische landbouw - tuinbouw - glastuinbouw - plantgezondheid - natuurlijke vijanden - agro-ecosystemen - biologische bestrijding - pesticiden
Conservation of natural enemies is an important component of pest management, which can improve their efficacy against target pests. Conserving predaceous Coccinelidae species in agricultural ecosystems is used to enhance their biocontrol contribution. Favourable conditions in these habitats can contribute to a more efficient population regulation of several pests. Conservation efforts focus on discouraging emigration from a crop system and enhance retention time of coccinelids in periods with low prey availability. Thus, the management of agroecosystems should focus on providing resources in such temporal and spatial scale that may prevent their emigration or attract them in habitats. In addition, in a greenhouse ecosystem, another conservation action is to reduce mortality and sublethal effects caused by insecticides.
Masterplan tripsbestrijding in bloemisterijgewassen
Messelink, G.J. ; Leman, A. ; Weel, P.A. van; Holstein, R. van; Vijverberg, Roland ; Kruidhof, H.M. ; Huang, T. ; Wiegers, G.L. ; Tol, R.W.H.M. van - \ 2016
Wageningen : Wageningen UR Glastuinbouw - 1 p.
tuinbouw - glastuinbouw - endofyten - natuurlijke vijanden - bestrijdingsmethoden - frankliniella occidentalis - chrysanthemum - rosaceae - alstroemeria - amaryllis - potplanten - tomatenbronsvlekkenvirus - afdekken - vallen - windtunnels - horticulture - greenhouse horticulture - endophytes - natural enemies - control methods - pot plants - tomato spotted wilt virus - casing - traps - wind tunnels
Het doel van dit project is om tot betere bestrijdingsstrategieën van trips in de sierteelt onder glas te komen door 1) een weerbaarder gewas met endofyten, 2) preventieve inzet van natuurlijke vijanden en 3) gedragsmanipulatie van volwassen tripsen. Deze pijlers worden vervolgens geïntegreerd tot een systeemaanpak. Poster van het PlantgezondheidEvent 2016.
Getting prepared for future attack : induction of plant defences by herbivore egg deposition and consequences for the insect community
Pashalidou, F.G. - \ 2015
Wageningen University. Promotor(en): Marcel Dicke; Joop van Loon, co-promotor(en): Nina Fatouros. - Wageningen : Wageningen University - ISBN 9789462574120 - 168
insect-plant relaties - planten - insectenplagen - herbivorie - verdedigingsmechanismen - geïnduceerde resistentie - herbivoor-geinduceerde plantengeuren - ovipositie - natuurlijke vijanden - brassica - pieris brassicae - trofische graden - sluipwespen - hyperparasitoïden - insectengemeenschappen - insect plant relations - plants - insect pests - herbivory - defence mechanisms - induced resistance - herbivore induced plant volatiles - oviposition - natural enemies - trophic levels - parasitoid wasps - hyperparasitoids - insect communities

Plants have evolved intriguing defences against insect herbivores. Compared to constitutive Plants have evolved intriguing defences against insect herbivores. Compared to constitutive defences that are always present, plants can respond with inducible defences when they are attacked. Insect herbivores can induce phenotypic changes in plants and consequently these changes may differentially affect subsequent attackers and their associated insect communities. Many studies consider herbivore-feeding damage as the first interaction between plants and insects. The originality of this study was to start with the first phase of herbivore attack, egg deposition, to understand the consequences of plant responses to eggs on subsequently feeding caterpillars and their natural enemies. The main plant species used for most of the experiments was Brassica nigra (black mustard), which occurs naturally in The Netherlands. The main herbivore used was the lepidopteran Pieris brassicae, which lays eggs in clusters and feeds on plants belonging to the Brassicaceae family. This study investigated plant-mediated responses to oviposition and their effects on different developmental stages of the herbivore, such as larvae and pupae. Furthermore, the effects of oviposition were extended to four more plant species of the same family, and to higher trophic levels including parasitoids and hyperparasitoids. The experiments were conducted under laboratory, semi-field and field conditions. This study shows that B. nigra plants recognize the eggs of P. brassicae and initiate resistance against subsequent developmental stages of the herbivore. Interestingly, plant responses to oviposition were found to be species specific. Plants did not respond to egg deposition by another herbivore species, the generalist moth Mamestra brassicae. Moreover, most of the Brassicaceae species tested were found to respond to P. brassicae eggs, which indicates that plant responses against oviposition are more common among the family of Brassicaceae. To assess effects on other members of the food chain, the effects of oviposition on plant volatile emission and the attraction of parasitic wasps, such as the larval parasitoid Cotesia glomerata, were tested. It was shown that the wasps were able to use the blend of plant volatiles, altered by their hosts’ oviposition, to locate young caterpillars just after hatching from eggs. The observed behaviour of the wasps was associated with higher parasitism success and higher fitness in young hosts. Similar results were obtained in a field experiment, where plants infested with eggs and caterpillars attracted more larval parasitoids and hyperparasitoids and eventually produced more seeds compared to plants infested with caterpillars only. This study shows that an annual weed like B. nigra uses egg deposition as reliable information for upcoming herbivory and responds accordingly with induced defences. Egg deposition could influence plant-associated community members at different levels in the food chain and benefit seed production. As the importance of oviposition on plant-herbivore interactions is only recently discovered, more research is needed to elucidate the mechanisms that underlie such plant responses and how these interactions affect the structure of insect communities in nature.

Hoe meer diversiteit hoe beter? : onderzoek naar de effecten van biodiversiteit lijken veelbelovend: wordt vervolgd
Apeldoorn, D.F. van; Rossing, W.A.H. ; Oomen, G.J.M. - \ 2015
Ekoland (2015)februari. - ISSN 0926-9142 - p. 26 - 27.
agrobiodiversiteit - teeltsystemen - gewasteelt - gemengde teelt - strokenteelt - veldgewassen - natuurlijke vijanden - agro-biodiversity - cropping systems - crop management - mixed cropping - strip cropping - field crops - natural enemies
Ecologen zijn het er over eens, diversiteit draagt bij aan de stabiliteit van ecosystemen. En met dit inzicht wordt er nu ook binnen de landbouw volop geëxperimenteerd. Maar waar ligt de grens?
Mogelijkheden voor bladluisbestrijding met schimmels
Messelink, G.J. ; Holstein-Saj, R. van; Dinu, M.M. ; Bloemhard, C.M.J. - \ 2015
gewasbescherming - tuinbouw - glastuinbouw - capsicum - plagenbestrijding - biologische bestrijding - aphididae - natuurlijke vijanden - kasproeven - entomopathogene schimmels - conferenties - plant protection - horticulture - greenhouse horticulture - pest control - biological control - natural enemies - greenhouse experiments - entomogenous fungi - conferences
Doelstelling: Bepalen welke soorten entomopathogene schimmels het meest kansrijk zijn voor de bestrijding van bladluizen in kasteelten en wat de randvoorwaarden zijn voor een geslaagde bestrijding. Poster van PlantgezondheidEvent 12 maart 2015.
Increase of plant resistance with rhizosphere competent entomopathogenic fungi (EPF)
Tol, R.W.H.M. van - \ 2015
gewasbescherming - tuinbouw - entomopathogene schimmels - biologische bestrijding - rizosfeer - natuurlijke vijanden - bodeminsecten - insect-plant relaties - conferenties - melolontha melolontha - bodem-plant relaties - insectenplagen - plant protection - horticulture - entomogenous fungi - biological control - rhizosphere - natural enemies - soil insects - insect plant relations - conferences - soil plant relationships - insect pests
Entomopathogenic fungi are able to kill insects and are as such a potential mean for pest control. Recently it was discovered that these fungi can also colonize plant roots. Most previous work with EPF has ignored the habitat preferences and survival of the fungus outside of the host. It is possible that factors associated with fungal biology outside of the host are more important when selecting an isolate than how pathogenic it is against a particular host in a laboratory bioassay. Poster van PlantgezondheidEvent 12 maart 2015.
Quantifying and simulating movement of the predator carabid beetle Pterostichus melanarius in arable land
Allema, A.B. - \ 2014
Wageningen University. Promotor(en): Joop van Lenteren, co-promotor(en): Walter Rossing; Wopke van der Werf. - Wageningen : Wageningen University - ISBN 9789461739100 - 133
bouwland - insectenplagen - natuurlijke vijanden - roofinsecten - predatoren - pterostichus melanarius - verspreiding - beweging - diergedrag - kwantitatieve analyse - motiliteit - modelleren - methodologie - arable land - insect pests - natural enemies - predatory insects - predators - dispersal - movement - animal behaviour - quantitative analysis - motility - modeling - methodology

Keywords: landscape entomology, movement ecology, quantifying movement, population spread, habitat heterogeneity, motility, edge-behaviour, diffusion model, model selection, inverse modelling, Pterostichus melanarius, Carabidae, entomophagous arthropod

Biological control provided by entomophagous arthropods is an ecosystem service with the potential to reduce pesticide use in agriculture. The distribution of entomophagous arthropods and the associated ecosystem service over crop fields is affected by their dispersal capacity and landscape heterogeneity. Current knowledge on entomophagous arthropod distribution and movement patterns, in particular for soil dwelling predators, is insufficient to provide advice on how a production landscape should be re-arranged to maximally benefit from biological pest control. Movement has mainly been measured in single habitats rather than in habitat mosaics and as a consequence little information is available on behaviour at habitat interfaces, i.e. the border between two habitats.

This study contributes to insight into movement patterns of the entomophagous arthropod Pterostichus melanarius (Illiger) in an agricultural landscape as a knowledge basis for redesign of landscapes for natural pest control. Movement patterns were studied with video equipment in experimental arenas of 5 m2 and with mark-recapture at much larger scales in the field. Interpretation of the results was supported by diffusion models that accounted for habitat specific motility µ (L2 T−1), a measure for diffusion of a population in space and time, and preference behaviour at habitat interfaces.

Movement of carabids has mostly been quantified as movement rate, which cannot be used for scaling-up. Available information on movement rate of carabids was made available for scaling-up by calculating motility from published data and looking for patterns through meta-analysis of data from thirteen studies, including 55 records on twelve species. Beetles had on average a three times higher motility in arable land than in forest/hedgerow habitat. The meta-analysis did not identify consistent differences in motility at the individual species level, and a grouping of species according to gender or size did not demonstrate a significant gender or size effect.

A methodology to directly estimate motility from data using inverse modelling was evaluated on data of a mass mark-recapture field experiment in a single field of winter triticale (x Triticosecale Wittmack.). Inverse modelling yielded the same result as motility calculated from squared displacement distances. In the first case, motility was calculated as an average over motility of individuals, in the second case motility was estimated from a population density distribution fitted to the recapture data. The similarity in motility between these two very different approaches strengthens the confidence in motility as a suitable concept for quantifying dispersal rate of carabid beetles, and in inverse modelling as a method to retrieve movement parameters from observed patterns.

The effect of habitat heterogeneity on movement behaviour was studied for P. melanarius across adjacent fields of oilseed radish (Raphanus sativus) and rye (Secale cereale) in a mark-recapture experiment. The field study was complemented by observations on movement behaviour in the experimental arena. Motility was neither significantly different between the crop species in the field nor in the arena. Overall movement in the field was significantly affected by behaviour at the interface between the crops. Beetles moved more frequently from rye to oilseed radish than in the opposite direction. The arena data indicated greater frequency of habitat entry into oilseed radish as compared to rye. Analysis of video tracking data from the arena resulted in estimates of motility that, when scaled up were close to those obtained in the field. Thus, the studies at the smaller and larger scales gave qualitatively and quantitatively similar results.

The effect of habitat heterogeneity on within-season dispersal behaviour was further explored in an agricultural landscape mosaic comprising perennial strips and different crop species with distinct tillage management. Semi-natural grass margins were functionally different from the crop habitats. Motility was lower in margins than in crop habitats, and at the crop-margin interface more beetles moved towards the crop than to the margin. Margins thus effectively acted as barriers for dispersal. In the crop habitats motility differed between fields but no consistent relations were found with crop type, food availability or tillage. Based on the motility in crop habitats P. melanarius was predicted to disperse over a distance of about 100 – 160 m during a growing season in a landscape without semi-natural elements. Given this range little redistribution of beetles is expected between fields within a growing season, even more when fields are surrounded by grass margins or hedgerows, meaning that the success of biological control by this species is more dependent on field management affecting local population dynamics than on habitat heterogeneity.

This thesis has resulted in a methodological approach to quantify dispersal behaviour of ground-dwelling insects from mark-recapture data in heterogeneous environments using inverse modelling. The combination of models and data proved to be powerful for studying movement and contributes to the development of predictive dynamic models for population spread of entomophagous arthropods. These models for population spread may be used as part of multi-objective assessment of alternative landscape configurations to find spatial arrangements of land use that maximize the ecosystem service of biological control as part of a wider set of landscape functions.

Predation threats to the Red-billed Tropicbird breeding colony of Saba: focus on cats
Debrot, A.O. ; Ruijter, M. ; Endarwin, W. ; Hooft, P. van; Wulf, K. - \ 2014
Den Helder : IMARES (Report / IMARES Wageningen UR C011/14) - 53
natuurlijke vijanden - vogels - predatie - katten - inventarisaties - caribisch gebied - natural enemies - birds - predation - cats - inventories - caribbean
Feral domestic cats (Felis catus) are recognized as one of the most devastating alien predator species in the world and are a major threat to nesting colonies of the Red-billed Tropicbird (Phaethon aethereus), on Saba island, Dutch Caribbean. Cats and rats are both known to impact nesting seabirds and hence are both potential threats to the tropicbird on Saba. However, whereas the tropicbird has coexisted with rats for centuries, cats have only recently become a problem (since about 2000). Several studies from the region suggest that the tropicbird may be less-vulnerable to rats but cats have been unequivocally implicated in the depredation of tropicbird nests on Saba (unpublished data, Michiel Boeken). In this study we collected baseline data on cat and rat distribution, and cat diet and health. We also conducted 83 questionnaire interviews with Saba residents to assess their views on cats, rats, tropicbirds and the acceptability of different management options.
Multitrophic interactions on a range-expanding plant species
Fortuna, T.F.M. - \ 2013
Wageningen University. Promotor(en): Louise Vet; J.A. Harvey. - Wageningen : Wageningen UR - ISBN 9789461737656 - 229
planten - invasieve soorten - geïntroduceerde soorten - herbivoren - ongewervelde dieren - natuurlijke vijanden - predatoren - parasitoïden - multitrofe interacties - bunias orientalis - verdedigingsmechanismen - plants - invasive species - introduced species - herbivores - invertebrates - natural enemies - predators - parasitoids - multitrophic interactions - defence mechanisms

Studies on the ecological impacts of exotic invasive plants have mainly focused on inter-continental invasions. However due to global environmental changes, a rapid increase in intra-continental range-expanding plants has been observed. In this context, multitrophic interactions between exotic plants, native herbivores and their natural enemies have been largely ignored. This thesis aimed at examining how an exotic range-expanding plant interacts with aboveground insect herbivores and their natural enemies and how it can contribute to the successful establishment of the exotic plant. In addition, it examines how resistance traits of different populations of the range-expander affect the behaviour and performance of herbivores and their natural enemies in the new habitat. Bunias orientalis (Capparales: Brassicaceae) is perennial plant from extreme south-eastern Europe and Asia that has recently expanded its range and become invasive in northern and central parts of Europe. In the Netherlands, it is considered naturalized but non-invasive.

Firstly, using a community approach, I found that Bu. orientalis suffered less herbivore damage and harboured smaller invertebrate communities than sympatric native Brassicaceae in the Netherlands. The exotic plant has been found of low quality for the larval growth of the specialist herbivore (Pieris brassicae). Furthermore, two of its gregarious parasitoids were differentially affected by the quality of the exotic plant. The pupal parasitoid (Pteromalus puparum) survived better than the larval parasitoid (Cotesia glomerata), and the latter parasitized less hosts on the exotic than on native plants. Therefore, the herbivore can be selected to adapt to the new plant by conferring an enemy free space to the herbivore. In this case, a plant shift by the specialist herbivore might occur and thus preventing the further spread of the exotic plant. Conversely, in the field I found greater carnivore pressure on Bu. orientalis compared to other native Brassicaceae, particularly in the peak of arthropod abundance. Hence, top-down forces exerted by herbivore natural enemies may act in concert with bottom-up control of plant resistance traits to counteract herbivore plant shift and promote the successful range expansion of the exotic plant.

Secondly, using a biogeographical approach, I found a considerable intraspecific variation in defence traits (trichomes, glucosinolates, metabolic fingerprints) of Bu. orientalis populations from the native and the exotic range. Plants collected in the native range were better defended than their exotic conspecifics. This variation matched with the performance of a generalist herbivore (Mamestra brassicae) and its parasitoid (Microplitis mediator), which developed poorly in plants from the native range. The results suggest that the defensive mechanisms of Bu. orientalis might have been counter-selected during the range expansion of the exotic plant. Further studies, however, need to examine if enemy release in the new range is followed by an increase in performance of the exotic plant. Finally, a comparative study of multitrophic interactions, both above- and belowground, in the plant native range and along the transect of its range expansion can help to clarify the mechanisms underlying the invasive success of Bu. orientalis.

Basiskennis roofmijten voor een betere plaagbestrijding : literatuurstudie naar de effecten van gewas, klimaat en licht op generalistische bladbewonende roofmijten
Messelink, G.J. ; Holstein, R. van - \ 2012
Bleiswijk : Wageningen UR Glastuinbouw (Rapport / Wageningen UR Glastuinbouw ) - 12
biologische bestrijding - organismen ingezet bij biologische bestrijding - roofmijten - phytoseiidae - plagenbestrijding - glastuinbouw - natuurlijke vijanden - trialeurodes vaporariorum - frankliniella occidentalis - kasgewassen - klimaat - belichting - biological control - biological control agents - predatory mites - pest control - greenhouse horticulture - natural enemies - greenhouse crops - climate - illumination
Doel van dit project is om de belangrijkste basiseigenschappen van generalistische roofmijten in kaart te brengen, om daarmee een beter advies te kunnen geven over de inzet van roofmijten in o.a. de teelt van potplanten. Gestart wordt met een literatuurstudie gevolgd door laboratoriumtesten met 6 soorten roofmijten. Deze publicatie beschrijft de literatuurstudie.
Bestrijding van citruswolluis in potplanten
Pijnakker, J. ; Leman, A. - \ 2012
Bleiswijk : Wageningen UR Glastuinbouw (Rapporten GTB 1181) - 41
potplanten - insectenplagen - planococcus citri - natuurlijke vijanden - glastuinbouw - insectenbestrijding - preventie - geïntegreerde bestrijding - nederland - pot plants - insect pests - natural enemies - greenhouse horticulture - insect control - prevention - integrated control - netherlands
Referaat Momenteel worden wolluizen vaak biologisch bestreden in binnentuinen van kantoren, zwembaden, dierentuinen en kassen bij botanische tuinen. De resultaten van biologische bestrijding zijn voor deze toepassingsgebieden over het algemeen goed, maar dit geldt niet voor commerciële productie in kassen. In commerciele productiekassen zijn enkele praktijkervaringen opgedaan met curatieve introducties van natuurlijke vijanden. De kever Cryptolaemus wordt vaak niet teruggevonden en introducties van sluipwespen op het moment dat wolluis wordt waargenomen komen vaak te laat. Dan moet alsnog met insecticiden worden ingegrepen. In dit onderzoek werd onderzocht of de continue inzet van natuurlijke vijanden de uitbreiding van wolluisaantasting naar nog niet aangetaste planten kan voorkomen en of kleine haarden curatief kunnen worden bestreden. Met de commercieel beschikbare sluipwespen en lieveheersbeestjes waren we in staat kleine haarden curatief te bestrijden en de aantastingen van wolluizen te verkleinen en te remmen, maar niet om de plaag volledig te bestrijden. Leptomastix dactylopii en Anagyrus pseudococci bleken betere bestrijders te zijn dan Coccidoxenoides perminutus. Beheersing van de plaag was niet mogelijk zonder correctie-bespuitingen met chemische gewasbeschermingsmiddelen omdat een nul tolerantie wordt gehanteerd in potplanten. Flonicamid bleek een effectief en selectief middel om haarden van wolluizen te bestrijden met weinig invloed om biologische bestrijders. Dit middel heeft echter geen toelating tegen wolluis in de glastuinbouw. Telers die een nultolerantie hanteren zullen de jonge planten met insecticiden behandelen, nauwkeurig scouten en pleksgewijs spuiten. Vaak leidt dit uiteindelijk tot volvelds spuiten. Technieken die vroege detectie mogelijk maken (sensoren, camera’s) zouden het scouten kunnen vereenvoudigen. Telers die de goedkoopste strategie willen kiezen, zullen kiezen voor het toepassen van selectieve chemische bestrijdingsmiddelen (neonicotinoïden). Telers met een tolerantie voor wolluis zullen wekelijks introducties van sluipwespen uitvoeren (10 sluipwespen/m2/week?). De overlevingskans van sluipwespen zou verhoogd kunnen worden, met behulp van bijvoorbeeld een suikerbron of nectarplanten, om de interval tussen introducties te kunnen vergroten. Een bankerplantsysteem wordt in 2012 ontwikkeld om de sluipwespen in de kas buiten het gewas in stand te houden of indien mogelijk te kweken. Abstract Currently, mealybugs are often controlled with natural enemies in organic gardens or offices, swimming pools, zoos and botanical gardens under glass. The results of biological control for these applications is generally good, but these are not applied in commercial greenhouses. In commercial production greenhouses growers have some practical experience with curative releases of natural enemies. The beetle Cryptolaemus is often not retrieved, and releases of wasps when mealybugs are observed are often too late. Then still insecticide intervention is needed. In this project we investigated whether the continuous use of natural enemies can prevent the expansion of mealybugs towards not infested plants and if they can control small hot-spots. With the commercially available parasitic wasps and ladybugs we were able to eliminate small hot-spots and reduce infestations of mealybugs, but we couldn’t fully exterminate the pest. Controlling mealybugs was not possible without corrective spraying with chemical pesticides because a zero tolerance policy is applied in potted plants. Flonicamid proved to be an effective and selective compound to control outbreaks of mealybugs with little impact on biological control agents. This product is unfortunately niet registerd against mealybugs in greenhouses in The Netherlands.
Kevertje Rhyzobius lophanthae goede bondgenoot tegen rozenschildluis
Arkesteijn, M. ; Pijnakker, J. ; Hennekam, M. - \ 2012
Onder Glas 9 (2012)5. - p. 39 - 41.
glastuinbouw - plantenplagen - snijbloemen - rozen - aphidoidea - rhyzobius lophanthae - organismen ingezet bij biologische bestrijding - natuurlijke vijanden - greenhouse horticulture - plant pests - cut flowers - roses - biological control agents - natural enemies
Rozenschildluis is een toenemend probleem in de rozenteelt. Het beestje is in 2009 voor het eerst op een rozenkwekerij gevonden. De schatting is dat de helft van de bedrijven besmet is. De plaag is chemisch niet te bestrijden met selectieve middelen. De kever Rhyzobius lophanthae lijkt voorlopig de beste bondgenoot in de strijd tegen het plaaginsect.
Risicobeperking van ziekten en plagen bij energiezuinige maatregelen
Hofland-Zijlstra, J.D. ; Messelink, G.J. ; Slooten, M.A. van; Groot, E.B. de; Stevens, L.H. - \ 2012
Bleiswijk : Wageningen UR Glastuinbouw (Rapporten GTB 1153) - 34
glastuinbouw - plantenplagen - plantenziekten - klimaatregeling - kooldioxide - vochtigheid - natuurlijke vijanden - gewasbescherming - ziekteresistentie - plaagresistentie - greenhouse horticulture - plant pests - plant diseases - air conditioning - carbon dioxide - humidity - natural enemies - plant protection - disease resistance - pest resistance
This study gives an overview on the impact of climatic conditions, e.g. moisture deficit and CO2, on the plant defense system in the greenhouse. Higher CO2 dosages or increased moisture levels have a strong influence on the pest control. Partly, by direct effects on biological control agents and partly through effects on the plant quality. The outcome depends on the prey-predator system.
Geïntegreerde bestrijding van citruswolluis Planococcus citri in roos
Pijnakker, J. ; Leman, A. ; Staaij, M. van der - \ 2011
Bleiswijk : Wageningen UR Glastuinbouw (Rapport / Wageningen UR Glastuinouw 1117) - 44
rozen - geïntegreerde plagenbestrijding - natuurlijke vijanden - planococcus citri - teelt onder bescherming - biologische bestrijding - roses - integrated pest management - natural enemies - protected cultivation - biological control
Abstract Since early 2000 the citrus mealybug, Planococcus citri (Risso), has become a key pest in roses cultivated in greenhouses in The Netherlands. While adopting a more integrated approach toward controlling (other) pests, growers have abandoned regular applications of broad spectrum pesticides, thus allowing mealybugs to become more widespread. Researchers have been investigating the benefits of both inundative releases of (commercial available) natural enemies of this pest. The relevance of introducing natural enemies for controlling mealybugs on greenhouse roses is discussed
FAB en gewasbescherming - Het belang van goed waarnemen.
Visser, A. ; Vlaswinkel, M.E.T. ; Wal, E. van der; Willemse, J. ; Alebeek, F.A.N. van - \ 2011
Lelystad : PPO AGV
akkerbouw - plaagbestrijding met natuurlijke vijanden - agrobiodiversiteit - gewasbescherming - functionele biodiversiteit - bevordering van natuurlijke vijanden - insectenplagen - natuurlijke vijanden - arable farming - augmentation - agro-biodiversity - plant protection - functional biodiversity - encouragement - insect pests - natural enemies
In combinatie met bloemrijke akkerranden biedt scouting een goede mogelijkheid om het gebruik van insecticiden tegen luizen in granen en consumptieaardappelen te minimaliseren. In de toekomst zullen, onder andere door de hogere milieueisen, steeds minder gewasbeschermingsmiddelen toegelaten zijn. Het stimuleren van natuurlijke vijanden zal een steeds belangrijkere rol gaan spelen in het voorkomen van plagen in het gewas. Goed scouten is daarbij belangrijk. De tijd die nodig is voor een keer scouten ligt gemiddeld op ongeveer 20 minuten per perceel van ca. 5 hectare. Afhankelijk van het gewas, groeistadium en de luisdruk is het nodig om per seizoen 4-7 keer te scouten, om een goed beeld te krijgen en te houden van de situatie in het gewas
Akkernatuur : herkenningsboekje bloeiend bedrijf
Bos, M. - \ 2011
Driebergen : Louis Bolk Instituut
agrobiodiversiteit - functionele biodiversiteit - akkerbouw - bevordering van natuurlijke vijanden - natuurlijke vijanden - akkerranden - nuttige insecten - agro-biodiversity - functional biodiversity - arable farming - encouragement - natural enemies - field margins - beneficial insects
Dit boekje laat de minder opvallende, maar uiterst nuttige beestjes zien die u op en rond akkers tegen kunt komen. Iedereen kan deze groepen herkennen en actief inzetten voor natuurlijke plaagbeheersing.
Handleiding Scouting consumptie aardappel
Wal, E. van der; Bos, M. - \ 2011
Bloeiend Bedrijf
insectenplagen - natuurlijke vijanden - consumptieaardappelen - tellen - akkerbouw - akkerranden - insect pests - natural enemies - table potatoes - counting - arable farming - field margins
Handleiding voor het tellen van plaaginsecten en hun natuurlijk vijanden in consumptieaardappelen op akkers met akkerranden.
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