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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    Participatory appraisal of institutional and political constraints and opportunities for innovation to address parasitic weeds in rice
    Schut, M. ; Rodenburg, J. ; Klerkx, L.W.A. ; Hinnou, L.C. ; Kayeke, J. ; Bastiaans, L. - \ 2015
    Crop Protection 74 (2015). - ISSN 0261-2194 - p. 158 - 170.
    fed lowland rice - striga-hermonthica control - raais rapid appraisal - sub-saharan africa - socioeconomic constraints - integrated analysis - pest-management - systems - benin - tanzania
    Parasitic weeds in smallholder rice production systems, of which Striga asiatica, Striga hermonthica and hamphicarpa fistulosa are the main representatives, form an increasing problem for food and income security in sub-Saharan Africa (SSA). The objective of this paper is to identify institutional and political constraints and opportunities for innovation to address parasitic weed problems in rice. Constraints and opportunities for innovation were studied across three nested systems: the parasitic weed control system, the crop protection system, and the agricultural system. Multi-stakeholder workshops, interviews and surveys were held to gather data on key constraints faced by different stakeholder groups across three parasitic weed infested study sites in both Tanzania and Benin. The results demonstrate that in both countries, the majority of institutional and political constraints relate to the functioning of the broader crop protection and agricultural systems and not specifically to parasitic weeds. Although differences were observed between the two countries and the different stakeholder groups, the majority of constraints perceived by the stakeholders were caused by a lack of capabilities and resources and a limited access to credit. Awareness raising of parasitic weed problems among farmers, extension and crop protection officers at the local level, combined with improved input and service supply and enhanced agricultural education and training curricula at the national level, were identified as important elements for improvement. More structural collaboration between key stakeholder groups is expected to contribute to a better recognition of agricultural problems, like that of parasitic weeds in rice, and a more timely identification of feasible solutions.
    Socioeconomic and environmental assessment of biodiesel crops on family farming systems in Brazil
    Belo Leitea, J.G. Dal; Barbosa Justino, F. ; Nunes Vieira da Silva, J.V. ; Florin, M.J. ; Ittersum, M.K. van - \ 2015
    Agricultural Systems 133 (2015). - ISSN 0308-521X - p. 22 - 34.
    nitrogen-use efficiency - land-use systems - integrated assessment - ecological intensification - cereal production - ammonium-sulfate - cropping systems - pest-management - yield - agriculture
    In Brazil, local agricultural research agendas are increasingly challenged by the search for sustainable biodiesel crop options for family farmers, especially under semi-arid conditions. The aim of this paper is to explore the suitability of different biodiesel crops (i.e. soybean, castor bean and sunflower) through a set of environmental and socioeconomic indicators in a semi-arid (Montes Claros) and a more humid (Chapada Gaúcha) municipality in the state of Minas Gerais, southeast Brazil. A technical coefficient generator (TechnoGIN) was used to assess current (maize, beans, soybean and grass seed) and alternative (castor bean and sunflower) crops grown with current and alternative production techniques. The quantification of the inputs and outputs was based on farm surveys, expert knowledge, literature and field experiments. Although castor bean and sunflower are economically competitive with maize in Montes Claros, feed and labour requirements may hinder farmers' adoption. In Chapada Gaúcha, the double cropping system soybean/sunflower presented small economic gains when compared to soybean; it also increased nitrogen losses and biocide residues. We conclude that the scope for alternative and sustainable biodiesel crops on family farms is limited. Their economic benefits are small or absent, while their introduction can lead to higher environmental impacts and there may be trade-offs with food and feed availability at the farm level.
    Field evaluation of the efficacy of neem oil (Azadirachta indica A. Juss) and Beauveria bassiana (Bals.) Vuill. in cotton production
    Togbe, C.E. ; Haagsma, R. ; Zannou, E. ; Gbehounou, G. ; Déguénon, J.M. ; Vodouhe, S. ; Kossou, D. ; Huis, A. van - \ 2015
    Journal of Applied Entomology 139 (2015)3. - ISSN 0931-2048 - p. 217 - 228.
    threshold-based interventions - helicoverpa-armigera hubner - west-africa - metarhizium-anisopliae - entomopathogenic fungi - pest-management - spider-mite - insecticides - resistance - benin
    Neem oil (Azadirachta indica A. Juss) alone and combined with the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin (isolate Bb11) was applied to control cotton pests. The efficacy of these treatments was compared with that of synthetic insecticides applied either in a calendar-based application or in the ‘Lutte Etagée Ciblée’ (LEC) strategy, consisting of using first calendar-based (half-dose) applications followed by threshold-based treatments. The experiment was carried out in collaborative research with farmers in three cotton agro-ecological zones differing in rainfall, pest prevalence, and farming practices. The neem oil and neem oil-Bb11 treatments required 2 to 6 applications, while conventional and LEC received 6 to 8 applications. The percentage of damaged reproductive organs in plots treated with neem oil and neem oil plus Bb11 was higher than that recorded under the conventional and LEC strategy, with exception of the zone with the highest rainfall; this resulted in yields being 25% and 39% lower, respectively. Yields in the biopesticide plots were 26–42% higher and in the conventional and LEC plots 44–59% higher than those in the control plots that received only water. Overall, the LEC regime scored best, both in yield and profitability. The incidence of natural enemies was highest in the control and in the plots treated with biopesticides. Although the use of entomopathogen Bb11 and neem oil avoids many problems associated with the application of synthetic insecticides, their efficacy needs to be enhanced by improved formulation or by combining them with other pesticides.
    Lessons from Agriculture for the Sustainable Management of Malaria Vectors
    Thomas, M.B. ; Godfray, H.C.J. ; Read, A.F. ; Berg, H. van den; Tabashnik, B.E. ; Lenteren, J.C. van; Waage, J.K. ; Takken, W. - \ 2012
    PLOS Medicine 9 (2012)7. - ISSN 1549-1676
    anopheles-gambiae - pest-management - insecticide resistance - borne diseases - field trial - mosquito - strategies - impacts - africa - system
    The effectiveness of insecticide-treated bed nets and indoor insecticide sprays to control adult mosquito vectors is being threatened by the spread of insecticide resistance. We argue for expanding beyond “insecticide monotherapy” to more sustainable integrated vector management strategies that use optimal suites of control tactics. Experience in agriculture suggests that such integrated approaches can provide more effective and durable pest management. This shift will require increased investment in research and translational science. Failure to act risks a resurgence of malaria and erosion of community support and donor commitment.
    The state of commercial augmentative biological control: plenty of natural enemies, but a frustrating lack of uptake
    Lenteren, J.C. van - \ 2012
    BioControl 57 (2012)1. - ISSN 1386-6141 - p. 1 - 20.
    environmental risk-assessment - pest-management - pesticides - challenges
    Augmentative biological control concerns the periodical release of natural enemies. In com- mercial augmentative biological control, natural enemies are mass-reared in biofactories for release in large numbers to obtain an immediate control of pests. The history of commercial mass production of natural enemies spans a period of roughly 120 years. It has been a successful, environmentally and eco- nomically sound alternative for chemical pest control in crops like fruit orchards, maize, cotton, sugar cane, soybean, vineyards and greenhouses. Currently, aug- mentative biological control is in a critical phase, even though during the past decades it has moved from a cottage industry to professional production. Many efficient species of natural enemies have been discovered and 230 are commercially available today. The industry developed quality control guidelines, mass production, shipment and release methods as well as adequate guidance for farmers. However, augmentative biological control is applied on a frustratingly small acreage. Trends in research and application are reviewed, causes explaining the limited uptake are discussed and ways to increase application of augmentative biological control are explored.
    Biological control of invasive plant species: A stochastic analysis
    Chalak, S.M. ; Ruijs, A.J.W. ; Ierland, E.C. van - \ 2011
    Weed Biology and Management 11 (2011)3. - ISSN 1444-6162 - p. 137 - 151.
    integrated weed management - cirsium-arvense - sclerotinia-sclerotiorum - pest-management - new-zealand - resistance - dynamics - weevil - information - populations
    Biological control agents are regarded as a relatively safe method to control weeds. However, their impact on weeds can be relatively low and unpredictable. The aims of this article were to: (i) assess whether or not a weevil (Apion onopordi) and a mycoherbicide (Sclerotinia sclerotiorum) are desirable as biological agents for the control of Californian thistle (Cirsium arvense) in New Zealand despite their uncertain effectiveness; (ii) identify the combination of control options that is optimal to control the thistle; (iii) analyze the economic consequences of excluding chemicals from the weed control strategy; and (iv) assess the feasibility of the eradication of this weed. Two optimization models were developed and compared: one deterministic model and one stochastic model. The results showed that taking into account the stochastic effectiveness of biological agents can change the optimal integrated strategy, particularly if the biological control agent is relatively expensive. However, for a cheaper biological agent, the stochastic efficacy is less likely to change the optimal control strategy. On the basis of the modeling results, the authors argue that, in the context of the agri-environmental setting of this article's case study, chemicals can be replaced by more environmentally friendly control options at a relatively low cost. The authors also show that the eradication of the thistle is unlikely, at least given the efficacy of the existing control methods.
    The banker plant method in biological control
    Huang, N. ; Enkegaard, A. ; Osborne, L.S. ; Ramakers, P.M.J. ; Messelink, G.J. ; Pijnakker, J. ; Murphy, G. - \ 2011
    Critical Reviews in Plant Sciences 30 (2011)3. - ISSN 0735-2689 - p. 259 - 278.
    aphid rhopalosiphum-padi - apparent competition - population-dynamics - encarsia-formosa - pest-management - trialeurodes-vaporariorum - aleyrodes-proletella - alternative host - gossypii glover - homoptera
    In the banker plant method, long-lasting rearing units for beneficials are created in the crop by distributing plants infested with herbivores or carrying other food items, such as pollen. The method has been widely investigated over many years and used to aid establishment, development and dispersal of beneficial organisms employed in biological control. In this review, we refine the definition of the banker plant method based on previous concepts and studies and offer the term “banker plant system” to describe the unit that is purposefully added to or established in a crop for control of pests in greenhouses or open field. The three basic elements of a banker plant system (banker plant, food source, beneficials) are discussed and illustrated with examples, and the diversity of banker plant systems (classified by target pest) used or investigated is documented. The benefits of using banker plant systems, such as low cost, increased freshness of beneficials, possibility for preventive control and for integration within IPM frameworks, make the method an interesting plant protection option with potential to enhance adoption of biological control in pest management programs.
    Effect of learning on the oviposition preference of field-collected and laboratory-reared Chilo partellus (Lepidoptera: Crambidae) populations
    Glas, J.J. ; Berg, J. van den; Potting, R.P.J. - \ 2007
    Bulletin of Entomological Research 97 (2007)4. - ISSN 0007-4853 - p. 415 - 420.
    helicoverpa-armigera lepidoptera - swinhoe lepidoptera - phytophagous insects - hubner lepidoptera - pest-management - busseola-fusca - host plants - stem borer - noctuidae - pyralidae
    Recent studies show that Vetiver grass, (Vetiveria zizanioides (L.) Nash), may have potential as a dead-end trap crop in an overall habitat management strategy for the spotted stem borer, Chilo partellus (Swinhoe) (Lepidoptera: Crambidae). Vetiver grass is highly preferred for oviposition, in spite of the fact that larval survival is extremely low on this grass. The oviposition behaviour of female Chilo partellus moths was investigated by determining the amount and size of egg batches allocated to maize and Vetiver plants and studying the effect of rearing conditions and oviposition experience on host plant selection. Two-choice preference tests were used to examine the effect of experience of maize (a suitable host plant) and Vetiver plants on the oviposition choice of C. partellus. For both field-collected and laboratory-reared moths, no significant differences were found in the preference distributions between the experienced groups. It is concluded that females do not learn, i.e. that they do not change their preference for Vetiver grass after having experienced oviposition on either maize or this grass, which supports the idea that trap cropping could have potential as a control method for C. partellus. Differences observed between field-collected and laboratory-reared moths in the amount and size of egg batches laid on maize and Vetiver grass indicate that data obtained from experiments with laboratory-reared insects should be treated with caution.
    Olfactory responses of banana weevil predators to volatiles from banana pseudostem tissue and synthetic pheromone
    Tinzaara, W. ; Gold, C.S. ; Dicke, M. ; Huis, A. van - \ 2005
    Journal of Chemical Ecology 31 (2005)7. - ISSN 0098-0331 - p. 1537 - 1553.
    induced plant volatiles - infested pear trees - sordidus germar col - cosmopolites-sordidus - aggregation pheromone - parasitic wasps - pest-management - bark beetles - chemical communication - carnivorous arthropods
    As a response to attack by herbivores, plants can emit a variety of volatile substances that attract natural enemies of these insect pests. Predators of the banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae) such as Dactylosternum abdominale (Coleoptera: Hydrophilidae) and Pheidole megacephala (Hymenoptera: Formicidae), are normally found in association with weevil-infested rotten pseudostems and harvested stumps. We investigated whether these predators are attracted to such environments in response to volatiles produced by the host plant, by the weevil, or by the weevil¿plant complex. We evaluated predator responses towards volatiles from banana pseudostem tissue (synomones) and the synthetic banana weevil aggregation pheromone Cosmolure+ in a two-choice olfactometer. The beetle D. abdominale was attracted to fermenting banana pseudostem tissue and Cosmolure+, whereas the ant P. megacephala was attracted only to fermented pseudostem tissue. Both predators were attracted to banana pseudostem tissue that had been damaged by weevil larvae irrespective of weevil presence. Adding pheromone did not enhance predator response to volatiles from pseudostem tissue fed on by weevils. The numbers of both predators recovered with pseudostem traps in the field from banana mats with a pheromone trap were similar to those in pseudostem traps at different distance ranges from the pheromone. Our study shows that the generalist predators D. abdominale and P. megacephala use volatiles from fermented banana pseudostem tissue as the major chemical cue when searching for prey
    Insect behavioural ecology and other factors affecting the control efficacy of agro-ecosystem diversification strategies
    Potting, R.P.J. ; Perry, J.N. ; Powell, W. - \ 2005
    Ecological Modelling 182 (2005)2. - ISSN 0304-3800 - p. 199 - 216.
    individual-based models - fruit-fly diptera - plant patch size - trap crops - ceutorhynchus assimilis - trichomalus perfectus - tephritidae damage - beetle coleoptera - herbivore density - pest-management
    In the last decade there is an increased interest in the design and use of diversified pest-suppressive agro-ecosystems. A diversification approach aims to manipulate the spatial dynamics of herbivores by adding a trap crop that attracts and retains herbivores in the non-crop area or by adding a disruptive crop that induces an emigration response. Empirical studies have shown that there is a wide variation in insect herbivore response to vegetation diversification. To increase the predictability and reliability of this approach it is necessary to understand the mechanisms underlying herbivore population response to diversified agro-ecosystems. We use a spatially explicit, individual-based, simulation framework, with a strong emphasis on the behavioural ecology of insects, to explore the factors that influence the population regulatory effect of agro-ecosystem diversification. The reported wide variation in population response of herbivores to diverse agro-ecosystems is replicated in this study. In our simulations we found that the population regulation effect of diversification can be positive, negative or negligible. Behavioural factors that influenced the spatial dynamics of herbivore populations were the colonisation pattern, movement speed and sensory mode of finding host plants. Simulations show that the strength of inhibition of flight by the trap crop (i.e. arrestment) is the most important parameter to manipulate the spatial dynamics of insects with post-alighting host recognition behaviour. For herbivore species that use olfactory or visual cues to find host plants, the mechanism of aggregation in the trap crop is a combination of attraction and arrestment and hence the population regulatory effect of the trap crop is higher compared to herbivores with post-alighting host recognition behaviour. An important factor that influences the efficacy of the disruptive cropping strategy is the strength of the emigration-inducing effect of the vegetation. The simulation framework is a valuable tool to test hypotheses on insect behaviour and dynamics in heterogeneous environments and can be used to determine optimal diversification systems and hence generate guidance for establishing environmentally benign pest control strategies
    A concept of food-web structure in organic arable farming systems
    Smeding, F.W. ; Snoo, G.R. de - \ 2003
    Landscape and Urban Planning 65 (2003). - ISSN 0169-2046 - p. 219 - 236.
    skylarks alauda arvensis - winter-wheat fields - southern england - population-dynamics - natural enemies - carabid beetles - pest-management - soil - agroecosystems - bioindicators
    A proposal for a descriptive or topological farm food web is derived from field observations and from references in literature. Important themes in the food-web theory are tentatively applied to this preliminary model, explaining differences between local farm food-web structures and how they are related to farm and/or ecological infrastructure (EI) management. Predictions are made for four different farm food-web structures for extremes of farm and environmental gradients corresponding to the length of organic duration and amount/quality of El. The implications with regard to farming practices and nature conservation are that both organic duration and the amount/quality of ecological infrastructure may contribute to ecosystem services and nature conservation. However, an optimisation of the farm food web with regard to ecosystem services, may possibly run counter to nature conservation goals. (C) 2003 Published by Elsevier Science B.V.
    Integrated approaches to root disease management in organic farming systems
    Bruggen, A.H.C. van; Termorshuizen, A.J. - \ 2003
    Australasian Plant Pathology 32 (2003)2. - ISSN 0815-3191 - p. 141 - 156.
    soil microbial communities - rhizoctonia-solani - cropping systems - winter-wheat - conventional farms - fertility amendments - nematode communities - chemical-properties - plant-pathogens - pest-management
    Conventional agriculture has had major environmental impacts, in particular with respect to soil degradation. Soil structure, fertility, microbial and faunal biodiversity have declined, and root diseases are common unless genetic resistance, soil fumigation and/or seed treatments are used. Primarily for environmental reasons and increasing demands for safe and healthy food from the public, farmers have switched over to organic production at an increasing rate. During a transition period of about 5 years, organic farmers may face problems with yield losses and pest or disease problems. However, in well-managed, long-term organic farms, soilborne diseases need not be a problem. Several studies in which disease severity was compared in organic and conventional farming systems (or with soils from those systems) showed that root diseases are generally less severe in organically than conventionally managed soils. The reasons for reduced root disease severity have seldom been investigated, although relationships with nitrogen supply or microbial diversity have sometimes been found. Crop protection in organic farming is generally not directed at controlling particular pathogens or pests but at management of the environment so that plants are able to withstand potential attacks. Resistant cultivars adapted to the local conditions are in demand among organic farmers. However, the main practices that contribute to disease control are long, balanced rotations, organic amendments and reduced tillage, all geared towards maintenance of the soil organic matter content and fertility. Organic farmers can make use of biological control agents and natural toxic compounds in plant extracts. However, these practices are methods of last resort.
    Survey of current crop management practices in a mixed-ricefield landscape, Mekong Delta, Vietnam - potential of habitat manipulation for improved control of citrus leafminer and citrus red mite
    Mele, P. van; Lenteren, J.C. van - \ 2002
    Agriculture, Ecosystems and Environment 88 (2002)1. - ISSN 0167-8809 - p. 35 - 48.
    pest-management - diversity - orchards - coconut - plants
    In the Mekong Delta, Vietnam, the citrus leafminer Phyllocnistis citrella (CLM) and the citrus red mite Panonychus citri are major pests in both sweet orange (Citrus sinensis) and Tieu mandarin (C. reticulata). Survey data indicate that these pest problems might be aggravated after farmers have completely destroyed the weed flora in their orchard. As citrus farmers only perceive the larger predators such as the weaver ant Oecophylla smaragdina and spiders, and have no idea about the existence of predatory mites or parasitoids, they do not know about potential positive attributes of weeds in pest management which sustain populations of natural enemies and their alternative food. IPM training programmes could use the weaver ant as an introduction to educating farmers about predatory mites and parasitoids, and should likewise emphasise the importance of beneficial asteraceous weeds such as Ageratum conyzoides. Non-crop trees such as Spondias dulcis, Mangifera indica, Eucalyptus tereticornis and Ceiba pentandra are commonly known to offer good refuge for the weaver ant. These trees should be further studied for their temporal contribution as food resource for other natural enemies of CLM and mites. Small adjustments of current weed management techniques are suggested to improve availability of pollen and nectar for beneficials at crucial moments in the cropping season, with due respect to implications at the landscape level.
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