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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    Biological control of Trialeurodes vaporariorum by Encarsia formosa on tomato in unheated greenhouses in the high altitude tropics
    Vis, R.M.J. de; Lenteren, J.C. van - \ 2008
    Bulletin of Insectology 61 (2008)1. - ISSN 1721-8861 - p. 43 - 57.
    parasite-host relationship - commercial glasshouse - population-dynamics - aphelinidae - aleyrodidae - netherlands
    Biological control of Trialeurodes vaporariorum (Westwood) by Encarsia formosa Gahan was tested during three consecutive production cycles (16-28 weeks) on a beef tomato (Solanum lycopersicum L.) crop in a glasshouse and a plastic greenhouse on the Bogota Plateau in Colombia. During the course of this study over the period 1997-1999, the mean temperature was around 16 °C in the plastic greenhouse and around 17 °C in the glasshouse. E. formosa was introduced at a rate of 3 adults per m2 per week in the 1997 production cycle, and at a rate of 3 and 5 pupae per m2 per week in 1998 and 1999, respectively. In 1997, the adult whitefly population increased exponentially to a peak of 76 adults per plant in the plastic greenhouse, while the whitefly population in the glasshouse reached a peak of only 12 adults per plant. The percentage parasitism fluctuated between 42 and 82% in the glasshouse and between 28 and 47% in the plastic greenhouse. In 1998, the T. vaporariorum population could not be brought under control in both greenhouses and reached a peak of 80 and 53 T. vaporariorum adults per plant in the plastic greenhouse and the glasshouse, respectively. Parasitism fluctuated between 55 and 97% in the glasshouse and between 32 and 84% in the plastic greenhouse. In 1999, biological control was successful in both greenhouses. Most of the time, populations of T. vaporariorum were lower than 1.2 adults per plant and parasitism by E. formosa was 80% or higher. We suggest that the higher temperature is the main reason for better parasitism in the glasshouse when compared to the plastic greenhouse. The successful results of 1999 show that biological control is possible under the short day and low temperature conditions of greenhouses situated in the high altitude tropics such as the Bogota Plateau. Recommendations are given for the application of E. formosa based on the results of these experiments.
    Intra- and interspecific host discrimination in arrhenotokous and thelytokous Eretmocerus spp.
    Ardeh, M.J. ; Jong, P.W. de; Lenteren, J.C. van - \ 2005
    Biological Control 33 (2005)1. - ISSN 1049-9644 - p. 74 - 80.
    biological-control - bemisia-tabaci - conspecific superparasitism - parasitized hosts - encarsia-formosa - egg parasitoids - biotype b - hymenoptera - aleyrodidae - aphelinidae
    Bemisia tabaci (Gennadius) is a serious pest of vegetable, ornamental, and agronomic crops throughout the world. To control B. tabaci, Eretmocerus eremicus Rose & Zolnerowich, and Eretmocerus mundus Mercet are considered the most effective parasitoids in dry tropical regions. In parasitoids, choosing the `right` hosts has direct consequences for their reproductive success and efficiency as biocontrol agent. Therefore, being able to discriminate a parasitized host from an unparasitized one would be important to prevent wasting time, eggs, and to reduce the mortality risk for their offspring. We evaluated intra- and interspecific host discrimination and the chance of super-parasitism or multi-parasitism in two populations of E. mundus (sexual and asexual) and E. eremicus. Different combinations and sequences of female introduction were carried out for the various populations and species. Experienced females avoided super-parasitism. However, naïve females did lay eggs under hosts that were previously parasitized by conspecific females. E. eremicus females avoided to multi-parasitize hosts parasitized by E. mundus. However, E. mundus females did multi-parasitize the hosts that had been parasitized earlier by E. eremicus. In the case of super-parasitism, the outcome showed that neither of the E. mundus populations was stronger, whereas in the case of multi-parasitism E. mundus appeared stronger than E. eremicus. Since those populations and species are morphologically similar a molecular method had to be developed to identify the outcome of super- or multi-parasitism, which is presented in Appendix A.
    Genetics of female functional virginity in the Parthenogenesis-Wolbachia infected parasitoid wasp Telenomus nawai (Hymenoptera: Scelionidae)
    Jeong, G.S. ; Stouthamer, R. - \ 2005
    Heredity 94 (2005)4. - ISSN 0018-067X - p. 402 - 407.
    sex - aphelinidae
    A lepidopteran egg parasitoid species Telenomus nawai consists of two distinct populations with different reproductive modes. One is a completely thelytokous population consisting of females only, whereas the other displays arrhenotokous reproduction where fertilized eggs develop into diploid females and unfertilized eggs into haploid males. Thelytoky in T. nawai is caused by a bacterial symbiont, the parthenogenesis-inducing (PI) Wolbachia. Recent theoretical studies have shown that when a PI-Wolbachia is spreading in a population, mutations that allow uninfected females to produce more male offspring will spread rapidly eventually becoming fixed. The consequence of such a mutation is that sexual reproduction is no longer successful in infected females. Here we determine the genetic basis of the females' inability to reproduce sexually by introgressing the genome of a thelytokous line into an arrhenotokous line. The results suggest that the mutations are recessive and inherited either as a single-locus major gene with some modifiers, or as two partially linked loci
    Host feeding in insect parasitoids: why destructively feed upon a host that excretes an alternative?
    Burger, W. ; Reijnen, T.M. ; Lenteren, J.C. van; Vet, L.E.M. - \ 2004
    Entomologia Experimentalis et Applicata 112 (2004)3. - ISSN 0013-8703 - p. 207 - 215.
    trialeurodes-vaporariorum homoptera - encarsia-formosa hymenoptera - alfalfa weevil coleoptera - aphytis-melinus - honeydew sugars - aphelinidae - aleyrodidae - food - strategies - evolutionary
    Host feeding is the consumption of host tissue by the adult female parasitoid. We studied the function of destructive host feeding and its advantage over non-destructive feeding on host-derived honeydew in the whitefly parasitoid Encarsia formosa Gahan (Hymenoptera: Aphelinidae). We allowed parasitoids to oviposit until they attempted to host feed. We either prevented or allowed host feeding. Parasitoids had access to sucrose solution, with or without additional access to honeydew. Parasitoids that were allowed to host feed did not have a higher egg load 20 or 48 h after host feeding than parasitoids prevented from host feeding. Host feeding did not increase the number of eggs matured within these periods, nor did the time spent host feeding positively affect any of these response variables. On the other hand, the presence of honeydew did have a positive effect on egg load 20 and 48 h after host feeding compared with parasitoids deprived of honeydew. Parasitoids with access to honeydew matured more eggs within these periods than honeydew-deprived parasitoids. Host feeding increased life expectancy, but this effect was nullified when honeydew was supplied after the host-feeding attempt. In conclusion, feeding on honeydew could be an advantageous alternative to host feeding in terms of egg quantity and longevity. This applies especially to parasitoids exploiting Homoptera, because these parasitoids can obtain honeydew from the host itself. It is possible that destructive host feeding has evolved to enable females to sustain the production of high-quality anhydropic eggs, which may be important in the parasitoid's natural environment. We argue that future studies should take natural alternative food sources into more consideration.
    Influence of pesticide treatments on the dynamics of whiteflies and associated parasitoids in snap bean fields
    Manzano, M.R. ; Lenteren, J.C. van; Cardona, C. - \ 2003
    BioControl 48 (2003). - ISSN 1386-6141 - p. 685 - 693.
    bemisia-tabaci homoptera - amitus-fuscipennis macgown - biological-control - encarsia-formosa - aleyrodidae - hymenoptera - platygasteridae - aphelinidae - toxicity
    To determine the influence of pesticide treatments on the population dynamics of the whiteflies Trialeurodes vaporariorum (Westwood) and Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) and their naturally occurring parasitoids, we performed field experiments on insecticide sprayed and unsprayed fields during a cropping season of snap bean in Pradera, Valle del Cauca, Colombia. Substantially larger populations of whitefly nymphs occurred in the unsprayed field than in the sprayed field. Parasitoids were more frequent in unsprayed than in sprayed fields with Encarsia nigricephala Dozier being more prevalent than Amitus fuscipennis MacGown & Nebeker. In sprayed fields the nymphs parasitized by E. nigricephala exceeded the unparasitized whitefly nymphs at the end of the cropping season. Our results suggest that while under current agricultural practices whiteflies on snap beans cannot be exclusively controlled by naturally occurring parasitoids, parasitoids may be integrated with chemical control in order to reduce crop damage.
    Searching and oviposition behaviour of Amitus fuscipennis, a parasitoid of the greenhouse whitefly
    Manzano, M.R. ; Lenteren, J.C. van; Cardona, C. - \ 2002
    Journal of Applied Entomology 126 (2002). - ISSN 0931-2048 - p. 528 - 533.
    trialeurodes-vaporariorum homoptera - bemisia-argentifolii homoptera - encarsia-formosa hymenoptera - reproductive-biology - host relationship - aleyrodidae - aphelinidae - platygasteridae
    Amitus fuscipennis MacGown & Nebeker (Hym., Platygasteridae) is a parasitoid of the greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hom., Aleyrodidae) on some crops as bean and snap bean ( both Phaseolus vulgaris L.) in Colombia. The searching and oviposition behaviour of A. fuscipennis was studied in the laboratory, using T. vaporariorum as a host on bean leaves. The parasitoid's basic search pathway consisted of walking, encountering the host, and drumming and probing it. While walking, the parasitoid stopped for short periods of time, partly to preen itself. Walking while searching comprised 61% of the adults' time budget and probing hosts represented 16%. After a host nymph was parasitized by A. fuscipennis, the parasitoid remained close by and continued searching for new hosts in the immediate vicinity. Such behaviour suggests area-restricted searching. The parasitoid preferred. first instars of T. vaporariorum for oviposition, resulting in long developmental times. Amitus fuscipennis had a high percentage of host acceptance resulting in a high percentage parasitism (60%) of all encountered hosts. Amitus fuscipennis, on average, walked faster before an oviposition (1.4 mm/s) than other whitefly parasitoids. The implications of these findings for the control of T. vaporariorum are discussed.
    The parasite-host relationship between Encarsia formosa (Hymenoptera: Aphelinidae) and Trialeurodes vaporariorum (Homoptera: Aleyrodidae) XXXIV. Life-history parameters of the greenhouse whitefly, Trialeurodes vaporariorum as a function of host plant and temperature
    Roermund, H.J.W. van; Lenteren, J.C. van - \ 1992
    Unknown Publisher (Wageningen Agricultural University papers 92-3) - ISBN 9789067542357 - 102
    insectenplagen - trialeurodes vaporariorum - aleyrodidae - gastheer parasiet relaties - planten - parasitisme - encarsia formosa - aphelinidae - biologische bestrijding - modellen - insect pests - trialeurodes vaporariorum - aleyrodidae - host parasite relationships - plants - parasitism - encarsia formosa - aphelinidae - biological control - models
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