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.

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Data from: Crop pests and predators exhibit inconsistent responses to surrounding landscape composition
Karp, Daniel S. ; Chaplin-Kramer, Rebecca ; Meehan, Timothy D. ; Martin, Emily A. ; DeClerck, Fabrice ; Grab, Heather ; Gratton, Claudio ; Hunt, Lauren ; Larsen, Ashley E. ; Martínez-Salinas, Alejandra ; Bianchi, F.J.J.A. ; Werf, W. van der - \ 2018
agroecology - biological control - natural enemies - pest control - pest - ecosystem services - landscape
The idea that noncrop habitat enhances pest control and represents a win–win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win–win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies.
Uncovering the economic value of natural enemies and true costs of chemical insecticides to cotton farmers in China
Huang, Jikun ; Zhou, Ke ; Zhang, Wei ; Deng, Xiangzheng ; Der Werf, Wopke van; Lu, Yanhui ; Wu, Kongming ; Rosegrant, Mark W. - \ 2018
Environmental Research Letters 13 (2018)6. - ISSN 1748-9318
biological control - economic value - insecticides - natural enemies - smallholder farming

Little empirical evidence on the economic value of biological control of pests at farm level is available to improve economic decision-making by farmers and policy makers. Using insect sampling and household survey in an integrated bio-economic analysis framework, this paper studies farmers' crop management practices in cotton in the North China Plain, and estimates the marginal value of natural enemies and costs of chemical insecticides to farmers. Ladybeetles (mainly Harmonia axyridis, Propylea japonica, and Coccinella septempunctata), the dominant natural enemy group that controls the primary pest (aphid) in cotton in our study area, provide a significant economic benefit that is unknown to the farmers. Even at the current high levels of insecticide use, an additional ladybeetle provides an economic benefit of 0.05 CNY (almost USD 0.01) to farmers. The use of broad-spectrum insecticides by farmers is alarmingly excessive, not only undermining farmers' cotton profitability but also inducing social costs as well as disruption of the natural pest suppression system. Doubling current ladybeetle density in cotton field could gain an estimated USD 300 million for cotton farmers in China, providing a strong economic case for policies to move the pest control system towards a more ecologically-based regime, with positive consequences for farm income and environmental health. With rising use of biological control service provided by natural enemies such as ladybeetles in cotton fields, significant falls in farmers' insecticide use would be expected, which could raise the value of ladybeetles and other natural enemies even further. The results indicate that there is an urgent need to rationalize inputs and move forward to improved agro-ecosystem management in smallholder farming system. Raising knowledge and awareness on the costs and value of biological pest control versus insecticides among farmers and policy makers and having effective extension service, are priorities towards achieving a more ecologically-based approach to crop protection on smallholder farms.

Kleine lieveheersbeestjes bieden perspectief tegen luizenprobleem: nuttig bij preventie van grote luisuitbraken
Messelink, Gerben - \ 2017
biological control - biological control agents - natural enemies - aphididae - greenhouse horticulture - sweet peppers - organic farming - propylea quatuordecimpunctata
Data from: Managing trap-nesting bees as crop pollinators: spatiotemporal effects of floral resources and antagonists
Dainese, Matteo ; Riedinger, Verena ; Holzschuh, Andrea ; Kleijn, D. ; Scheper, J.A. ; Steffan-Dewenter, Ingolf - \ 2017
ecosystem services - landscape context - mass-flowering crops - natural enemies - nesting resources - off-field practices - oilseed rape - resource limitation - solitary bees - top-down or bottom-up control
1. The decline of managed honeybees and the rapid expansion of mass-flowering crops increase the risk of pollination limitation in crops and raise questions about novel management approaches for wild pollinators in agroecosystems. Adding artificial nesting sites, such as trap nests, can promote cavity-nesting bees in agroecosystems, but effectiveness could be limited by the availability of floral resources in the surrounding landscape and by natural antagonists. 2. In two European regions, we exposed artificial trap nests in paired field boundaries adjacent to oilseed rape (OSR) fields or non-flowering crops for two years within 32 landscapes covering two independent gradients of OSR cover and semi-natural habitat (SNH) cover in the landscape. We analysed the effects of local and landscape-wide floral resource availability, land-use intensity, landscape complexity and natural antagonists on community composition and population dynamics of trap-nesting bees. 3. Number of brood cells showed a strong, three-fold increase in response to the additional nesting sites. Species richness and abundance of cavity-nesting bees that were active during OSR flowering increased significantly with increasing amount of early-season landscape-wide floral resource availability, such as the cultivation of OSR. Later foraging species benefited instead from the availability of late-season alternative flower resources or SNH cover once the mass-flowering had ceased. Density-dependent parasitism increased following mass-flowering, while no density-dependent effect was found during mass-flowering. 4. Structural equation modelling revealed that the influence of floral resource availability on community growth rate was mediated by community size. Community size showed a strong negative effect on community growth rate. Despite positive density-dependent parasitism, antagonists had only weak regulating effects on community growth rate. 5. Synthesis and applications. Trap-nesting bee populations grow markedly with the increasing availability of food resources in the landscape and effectiveness of trap nests is only marginally limited by natural antagonists. Thus, trap nests could be a simple pollinator-supporting strategy to accompany the current expansion of mass-flowering crops, and to ensure pollination services for insect-pollinated crops. Trap nests benefit not only early season active generalist bees during oilseed rape flowering but also species with later phenology if accompanied by other pollinator-supporting practices.
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.

Vogels en hun functie in de bestrijding van de eikenprocessierups
Vliet, Arnold van - \ 2016
thaumetopoea processionea - pest control - natural enemies - paridae - birds

In een artikel van mei 2015 in ‘Nature Today’ stelt auteur Siliva Hellingman dat voor het eerst werd vastgesteld dat pimpelmezen en koolmezen een belangrijke rol kunnen spelen bij de bestrijding van eikenprocessierupsen. Het is inmiddels bekend dat een groot aantal vogels zich te goed doet aan eikenprocessierupsen. Het stimuleren van de vogelstand zou wel eens een belangrijke rol kunnen spelen bij het onder controle krijgen van de eikenprocessierups.

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.
Fitness consequences of indirect plant defence in the annual weed, Sinapis arvensis
Gols, R. ; Wagenaar, R. ; Poelman, E.H. ; Kruidhof, M. ; Loon, J.J.A. van; Harvey, J.A. - \ 2015
herbivory - plant defence - insect-plant interactions - multitrophic interactions - natural enemies - parasitoid - plant fitness
1. Plant traits that enhance the attraction of the natural enemies of their herbivores have been postulated to function as an ‘indirect defence’. An important underlying assumption is that this enhanced attraction results in increased plant fitness due to reduced herbivory. This assumption has been rarely tested. 2. We investigated whether there are fitness consequences for the charlock mustard Sinapis arvensis, a short-lived outcrossing annual weedy plant, when exposed to groups of large cabbage white (Pieris brassicae) caterpillars parasitized by either one of two wasp species, Hyposoter ebeninus and Cotesia glomerata, that allow the host to grow during parasitism. Hyposoter ebeninus is solitary and greatly reduces host growth compared with healthy caterpillars, whereas C. glomerata is gregarious and allows the host to grow approximately as large as unparasitized caterpillars. Both healthy and parasitized P. brassicae caterpillars initially feed on the foliage, but later stages preferentially consume the flowers. 3. In a garden experiment, plants damaged by parasitized caterpillars produced more seeds than conspecific plants damaged by unparasitized caterpillars. Reproductive potential (germination success multiplied by total seed number) was similar for plants that were not exposed to herbivory and those that were damaged by parasitized caterpillars and lower for plants that were damaged by healthy unparasitized caterpillars. However, these quantitative seed traits negatively correlated with the qualitative seed traits, individual seed size and germination success, suggesting a trade-off between these two types of traits. 4. We show that parasitism of insect herbivores that feed on reproductive plant tissues may have positive fitness consequences for S. arvensis. The extent to which plant fitness may benefit depends on parasitoid lifestyle (solitary or gregarious), which is correlated with the amount of damage inflicted on these tissues by the parasitized host.
Duurzaamheidseffecten van akkerranden
Alebeek, Frans van - \ 2015
arable farming - sustainability - biodiversity - field margins - scientific research - pilot projects - apidae - bombus - pollinators - natural enemies - insect pests - birds - ornamental value - small mammals
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?
Inleiding tripsbrainstorm
Messelink, Gerben - \ 2015
thrips - insect control - plant protection - roses - greenhouse experiments - plant disease control - natural enemies - biological control - predatory mites - workshops (programs)
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.
Performance of Orius insidiosus after storage, exposure to dispersal material, handling and shipment processes
Bueno, V.H.P. ; Carvalho, L.M. ; Lenteren, J.C. van - \ 2014
Bulletin of Insectology 67 (2014)2. - ISSN 1721-8861 - p. 175 - 183.
augmentative biological-control - sauteri poppius heteroptera - hemiptera anthocoridae - natural enemies - say hemiptera - cold-storage - reproduction - predator - temperature - arthropods
Storage, handling and shipment procedures are important factors influencing the quality of biological control agents. This study aimed to evaluate biological parameters and performance of Orius insidiosus (Say) after different storage periods at low temperatures, after exposure to different dispersal materials in containers, and after handling the predator during the shipment and delivery processes. Storage periods were 2, 4, 6, 8, 10, 12, 14, 16, 18 and 20 days at temperatures of 5, 8, 10 and 12 ± 1 °C, RH 70 ± 10% and under continuous scotophase. A mix of 75% adults and 25% 5th instar nymphs of O. insidiosus was kept in plastic containers (200 mL) for a 72 h period, supplied with eggs of Anagasta kuehniella (Zeller) as food, farmer’s friend inflorescence (Bidens pilosa L.) as oviposition substrate and source of moisture, and one of the following dispersal materials: vermiculite + rice hulls (1:1), vermiculite, folded paper towels, sawdust, and coffee husk. Also, similar mixes of nymphs and adults were exposed to a 72 h shipment and delivery process. We found that O. insidiosus can be stored up to 10 days at 8 °C without loss of quality. Interestingly, storage of mated female predators results in a much higher fecundity post-storage than storage of virgin females. Vermiculite + rice hulls was by far the best dispersal material, and shipment of the predators by post during 72 h in Styrofoam boxes with plastic containers with vermiculite + rice hulls and A. kuehniella eggs did not negatively affect their survival and predation capacity. Our results can be used in planning mass-rearing and shipment, and to improve the quality of the predator O. insidiosus by using the right storage temperature, storage period and dispersal material.
Synergistic effects of direct and indirect defences on herbivore egg survival in a wild crucifer
Fatouros, N.E. ; Pineda, A. ; Huigens, M.E. ; Broekgaarden, C. ; Shimwela, M.M. ; Figueroa Candia, I.A. ; Verbaarschot, P. ; Bukovinszky, T. - \ 2014
Proceedings of the Royal Society. B: Biological Sciences 281 (2014)1789. - ISSN 0962-8452 - 9 p.
furcifera horvath homoptera - plant defense - trade-offs - antiherbivore defenses - natural enemies - fitness costs - brassica-rapa - resistance - oviposition - butterflies
Evolutionary theory of plant defences against herbivores predicts a trade-off between direct (anti-herbivore traits) and indirect defences (attraction of carnivores) when carnivore fitness is reduced. Such a trade-off is expected in plant species that kill herbivore eggs by exhibiting a hypersensitive response (HR)-like necrosis, which should then negatively affect carnivores. We used the black mustard (Brassica nigra) to investigate how this potentially lethal direct trait affects preferences and/or performances of specialist cabbage white butterflies (Pieris spp.), and their natural enemies, tiny egg parasitoid wasps (Trichogramma spp.). Both within and between black mustard populations, we observed variation in the expression of Pieris egg-induced HR. Butterfly eggs on plants with HR-like necrosis suffered lower hatching rates and higher parasitism than eggs that did not induce the trait. In addition, Trichogramma wasps were attracted to volatiles of egg-induced plants that also expressed HR, and this attraction depended on the Trichogramma strain used. Consequently, HR did not have a negative effect on egg parasitoid survival. We conclude that even within a system where plants deploy lethal direct defences, such defences may still act with indirect defences in a synergistic manner to reduce herbivore pressure.
Feeding preferences of the aphidophagous hoverfly Sphaerophoria rueppellii affect the performance of its offspring
Amorós-Jiménez, R. ; Pineda Gomez, A.M. ; Fereres, A. ; Marcos-García, M.A. - \ 2014
BioControl 59 (2014)4. - ISSN 1386-6141 - p. 427 - 435.
episyrphus-balteatus diptera - sweet-pepper greenhouses - biological-control - hymenopteran parasitoids - floral resources - insectary plants - natural enemies - cereal aphids - host-plant - body-size
Provision of additional floral resources in the crop is a successful strategy of conservation biological control for attracting several natural enemies including predatory syrphids. However, the selection of flower species is mainly based on visiting preferences, paying little attention to the link between preference and performance. In this study, we assess the influence of feeding on flowers of two insectary plants (sweet alyssum and coriander) and flowers of a crop species (sweet pepper) on performance of the parental and first generation of the syrphid Sphaerophoria rueppellii (Wiedemann) (Diptera: Syrphidae). We found that floral preference of the adults was linked to developmental performance of their offspring. Sweet alyssum was the flower most frequently visited by syrphid adults, enhancing adult body size and egg-to adult survival of the F1 generation.
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