A bead-based suspension array for the multiplexed detection of begomoviruses and their whitefly vectors
Brunschot, S.L. van; Bergervoet, J.H.W. ; Pagendam, D.E. ; Weerdt, M. de; Geering, A.D.W. ; Drenth, A. ; Vlugt, R.A.A. van der - \ 2014
Journal of Virological Methods 198 (2014). - ISSN 0166-0934 - p. 86 - 94.
leaf-curl-virus - time pcr assay - bemisia-tabaci - q biotypes - tomato - identification - geminiviruses - aleyrodidae - hemiptera - invasion
Bead-based suspension array systems enable simultaneous fluorescence-based identification of multiple nucleic acid targets in a single reaction. This study describes the development of a novel approach to plant virus and vector diagnostics, a multiplexed 7-plex array that comprises a hierarchical set of assays for the simultaneous detection of begomoviruses and Bemisia tabaci, from both plant and whitefly samples. The multiplexed array incorporates genus, species and strain-specific assays, offering a unique approach for identifying both known and unknown viruses and B. tabaci species. When tested against a large panel of sequence-characterized begomovirus and whitefly samples, the array was shown to be 100% specific to the homologous target. Additionally, the multiplexed array was highly sensitive, efficiently and concurrently determining both virus and whitefly identity from single viruliferous whitefly samples. The detection limit for one assay within the multiplexed array that specifically detects Tomato yellow leaf curl virus-Israel (TYLCV-IL) was quantified as 200 fg of TYLCV-IL DNA, directly equivalent to that of TYLCVspecific qPCR. Highly reproducible results were obtained over multiple tests. The flexible multiplexed array described in this study has great potential for use in plant quarantine, biosecurity and disease management programs worldwide. (C) 2014 Elsevier B.V. All rights reserved.
Torradoviruses are transmitted in a semi-persistent and stylet-borne manner by three whitefly vectors
Verbeek, M. ; Bekkum, P.J. van; Dullemans, A.M. ; Vlugt, R.A.A. van der - \ 2014
Virus Research 186 (2014). - ISSN 0168-1702 - p. 55 - 60.
plant-virus transmission - picorna-like virus - bemisia-tabaci - tomato - aleyrodidae - efficiency - diseases
Members of the genus Torradovirus (family Secoviridae, type species Tomato torrado virus, ToTV) are spherical plant viruses transmitted by the whitefly species Trialeurodes vaporariorum and Bemisia tabaci. Knowledge on the mode of vector transmission is lacking for torradoviruses. Here, the mode of transmission was determined for Tomato marchitez virus (ToMarV). A minimal acquisition access period (AAP) and inoculation access period (IAP) of approximately 2h each was required for its transmission by T. vaporariorum, while optimal transmission required an AAP and IAP of at least 16h and 8h, respectively. Whiteflies could retain the virus under non-feeding conditions for at least 8h without loss of transmission efficiency, but upon feeding on a non-host plant in between the AAP and IAP they retained the virus for no more than 8h. Similar conditions supported transmission of isolates of ToTV and Tomato chocolàte virus (ToChV) by T. vaporariorum and B. tabaci. Additionally, similar experiments revealed the banded-winged whitefly (Trialeurodes abutilonea) as a vector for all three virus species. The results are congruent with acquisition and retention periods for semi-persistent virus transmission. RT-PCR detection analysis of ToTV and ToMarV in the vector's body revealed their presence in the stylet, but not in the head where the pharynx of the foregut is located. The results altogether indicate a semi-persistent stylet-borne mode of vector transmission for torradoviruses. Additionally, this is the first group of spherical viruses transmitted by at least three different species of whiteflies
Comparative antifeedant activities of polygodial and pyrethrins against whiteflies (Bemisia tabaci) and aphids (Myzus persicae)
Prota, N. ; Bouwmeester, H.J. ; Jongsma, M.A. - \ 2014
Pest Management Science 70 (2014)4. - ISSN 1526-498X - p. 682 - 688.
drimane sesquiterpenoids - biological-control - plant-viruses - trpa1 - insecticides - microcapsules - transmission - aleyrodidae - penetration - parasitoids
BACKGROUND Polygodial, a sesquiterpene dialdehyde of the drimane family, has been shown to have deterrent and antifeedant effects on various insect species, including Myzus persicae (Sulzer), Spodoptera spp. and Leptinotarsa decemlineata (Say). This compound may have potential as a broad-spectrum biocontrol agent, similar to pyrethrins, given that it was previously reported to improve yield when sprayed on barley fields. RESULTS This study compares the deterrent effect of polygodial and pyrethrins against the silverleaf whitefly Bemisia tabaci (Gennadius) and the green peach aphid M. persicae in dual-choice assays using compound-coated tomato leaf discs. B. tabaci adults were deterred by polygodial at an ED50 (effective dose at which 50% of the insects are deterred) of about 25 µg g-1 fresh weight (FW), and green peach aphids at about 54 µg g-1 FW. Bioassays were benchmarked with pyrethrins that had a 20-fold lower ED50 of approximately 1.4 µg g-1 FW against whiteflies, but only a twofold lower ED50 (about 28 µg g-1 FW) against peach aphids. Polygodial showed moderate phytotoxic effects (score of 2 on a scale of 1–5) on tomato leaves at concentrations above the ED50 concentrations (=90 µg g-1 FW). CONCLUSION The sesquiterpene dialdehyde polygodial is 2–20 times less deterrent than pyrethrins, depending on the insect species, but it could provide a useful complement to pyrethrin sprays as it has a different mode of action, is food grade and has low volatility. However, a formulation that reduces the risks of phytotoxic effects should be developed. © 2013 Society of Chemical Industry
Identification and QTL mapping of whitefly resistance components in Solanum galapagense
Firdaus, S. ; Heusden, A.W. van; Hidayati, N. ; Supena, E.D.J. ; Mumm, R. ; Vos, R.C.H. de; Visser, R.G.F. ; Vosman, B. - \ 2013
Theoretical and Applied Genetics 126 (2013)6. - ISSN 0040-5752 - p. 1487 - 1501.
hirsutum f-glabratum - bemisia-tabaci - lycopersicon-pennellii - wild tomato - glandular trichomes - frankliniella-occidentalis - feeding-behavior - pest resistance - biotype-b - aleyrodidae
Solanum galapagense is closely related to the cultivated tomato and can show a very good resistance towards whitefly. A segregating population resulting from a cross between the cultivated tomato and a whitefly resistant S. galapagense was created and used for mapping whitefly resistance and related traits, which made it possible to study the genetic basis of the resistance. Quantitative trait loci (QTL) for adult survival co-localized with type IV trichome characteristics (presence, density, gland longevity and gland size). A major QTL (Wf-1) was found for adult survival and trichome characters on Chromosome 2. This QTL explained 54.1 % of the variation in adult survival and 81.5 % of the occurrence of type IV trichomes. A minor QTL (Wf-2) for adult survival and trichome characters was identified on Chromosome 9. The major QTL was confirmed in F3 populations. Comprehensive metabolomics, based on GCMS profiling, revealed that 16 metabolites segregating in the F2 mapping population were associated with Wf-1 and/or Wf-2. Analysis of the 10 most resistant and susceptible F2 genotypes by LCMS showed that several acyl sugars were present in significantly higher concentration in the whitefly resistant genotypes, suggesting a role for these components in the resistance as well. Our results show that whitefly resistance in S. galapagense seems to inherit relatively simple compared to whitefly resistance from other sources and this offers great prospects for resistance breeding as well as elucidating the underlying molecular mechanism(s) of the resistance.
Identification of silverleaf whitefly resistance in pepper
Firdaus, S. ; Heusden, S. van; Harpenas, Asep ; Supena, E.D.J. ; Visser, R.G.F. ; Vosman, B. - \ 2011
Plant Breeding 130 (2011)6. - ISSN 0179-9541 - p. 708 - 714.
bemisia-argentifolii homoptera - hirsutum f-glabratum - trialeurodes-vaporariorum - sweet-pepper - wild tomato - aleyrodidae - tabaci - oviposition - cotton - insecticide
Whitefly is economically one of the most threatening pests of pepper worldwide, which is mainly caused by its ability to transmit many different viruses. In this research, we characterized pepper germplasm to identify whitefly-resistant accessions that will form the basis for future resistance breeding. Forty-four pepper accessions representing four species (Capsicum annuum, C. frutescens, C. chinense, C. baccatum) were screened for resistance to whiteflies. Screening parameters were adult survival (AS) and oviposition rate (OR) in a no-choice test and whitefly, egg and nymphal density in free-choice tests. To combine parameters in free-choice tests, a plant resistance value was calculated. The results show that AS and OR were significantly different among accessions and were positively correlated, which was also the case for the parameters in the free-choice tests. Accessions identified as highly resistant in no-choice and free-choice tests generally were C. annuum. Whitefly density and OR correlated positively with trichome density and negatively with cuticle thickness of leaves.
On-farm evaluation of integrated pest management of thrips and whiteflies in herb cuttings in Ethiopia : report to the Ministry of Agriculture and Rural Development
Belder, E. den; Elings, A. - \ 2010
Wageningen : Plant Research International (Report / Plant Research International 356) - 26
insectenplagen - thrips - aleyrodidae - stekken - geïntegreerde plagenbestrijding - biologische bestrijding - ethiopië - insect pests - thrips - aleyrodidae - cuttings - integrated pest management - biological control - ethiopia
Integrated Pest Management reduces the use of chemicals and therewith the impact of greenhouse horticulture on the environment. It improves working conditions and enables access of Ethiopian products on the world market. In response to such concerns the Ethiopian Horticulture Producers and Exporters Organization (EPHEA) has taken the initiative to develop a Code of Practice, of which Integrated Pest Management forms an integral part. The development of this Integrated Pest Management approach is supported through the Ethiopia-Netherlands Horticulture Partnership Programme.
Does Wolbachia infection affect Trichogramma atopovirilia behaviour?
Almeida, R.P. de; Lenteren, J.C. van; Stouthamer, R. - \ 2010
Brazilian Journal of Biology 70 (2010)2. - ISSN 1519-6984 - p. 435 - 442.
biological-control - parasitoid wasp - searching behavior - host selection - minutum - hymenoptera - brassicae - discrimination - aleyrodidae - temperature
Unisexual Trichogramma forms have attracted much attention due to their potential advantages as biocontrol agents. Fitness studies have been performed and understanding the cost that Wolbachia may inflict on their hosts will help in deciding if Wolbachia infected (unisexual) forms are indeed better than sexual forms when used in biological control programmes. The influence of Wolbachia on the foraging behaviour (including walking activity and speed) of T. atopovirilia is reported in this paper. Temperature strongly affected T. atopovirilia female walking activity, but Wolbachia infected and uninfected females differed in none of the behavioural components that were measured such as walking activity and walking speed. Walking activity was highest at 25 ºC and differed significantly from that at 20 and 15 ºC. Trichogramma wasps were highly affected at 15 ºC. Behaviour analysis with females showed that female wasps spend most of the time on drilling + ovipositing on host eggs followed by host drumming and walking while drumming. The parasitism rate and number of offspring did not differ significantly between infected and cured Trichogramma females. Biological control implications of these findings are discussed.
Evaluatie nieuwe wittevliegpredatoren op tomaat
Messelink, G.J. ; Holstein, R. van; Groot, E.B. de - \ 2010
Bleiswijk : Wageningen UR Glastuinbouw (Rapport / Wageningen UR Glastuinbouw 324) - 18
aleyrodidae - plaagbestrijding met natuurlijke vijanden - biologische bestrijding - predatoren - tomaten - solanum lycopersicum - glastuinbouw - vruchtgroenten - gewasbescherming - aleyrodidae - augmentation - biological control - predators - tomatoes - solanum lycopersicum - greenhouse horticulture - fruit vegetables - plant protection
In komkommer, aubergine en paprika is de wittevliegbestrijding aanzienlijk verbeterd sinds de introductie van de generalistische roofmijt Amblyseius swirskii. Op veel tomatenbedrijven gaat de biologische bestrijding van wittevlieg met roofwantsen en sluipwespen echter nog moeizaam in de winter-voorjaar-periode. In dit onderzoek hebben we vijf soorten roofmijten (Amblyseius swirskii, Euseius ovalis, Typhodromalus limonicus, Amslyseius montdorensis, Amslyseius alpinus) en voor soorten rooftripsen (Scolothrips sexmaculatus, Scolothrips longicornis, Scolothrips takahashii, Franklinothrips vespiformis) getest tegen kaswittevlieg in tomaat. In twee kasproeven met roofmijten konden alleen A. mondorensis en T. limonicus zich enige tijd op het gewas handhaven. Na 6 weken waren ook deze soorten verdwenen, ook al was er voldoende prooi beschikbaar. Bij geen enkele soort was er een effect op kaswittevlieg te zien. In het laboratorium bleken alle rooftripsen zich te voeden met eieren en larven van kaswittevlieg op tomatenblad. Géén van deze rooftripsen was echter in staat zich te vestigen op een tomatenplant met witte vlieg en er werd dan ook géén onderdrukkend effect op witte vlieg waargenomen. De slechte vestiging van de rovers is waarschijnlijk toe te schrijven aan de klierharen van tomaat, die bij contact kleverige en toxische stoffen afscheiden, waar kleine predatoren last van hebben.
Hyperparasitism behaviour of the autoparasitoid Encarsia tricolor on two secondary host species
Huang, Y. ; Loomans, A. ; Lenteren, J.C. van; RuMei, X. - \ 2009
BioControl 54 (2009)3. - ISSN 1386-6141 - p. 411 - 424.
trialeurodes-vaporariorum homoptera - formosa hymenoptera-aphelinidae - bemisia-argentifolii homoptera - biological-control - pergandiella hymenoptera - parasitoids hymenoptera - insect parasitoids - aleyrodidae - dynamics - selection
Hyperparasitism by virgin female Encarsia tricolor was studied by direct observation of its behaviour when contacting two secondary host species (Encarsia formosa and E. tricolor) at different host stages (first and second larval stage, third larval stage, and pupal stage). The searching and hyperparasitism behavioural sequence of E. tricolor was independent of the host stage of the whitefly (Aleyrodes proletella), and was similar to several related primary parasitoid species. In experiments with equal numbers of secondary hosts, encounter frequencies were equal for both secondary host species in all developmental stages observed. However, rates of hyperparastism were different according to host stage and host species. Hosts in the late larval stages were most preferred for hyperparasitization and the heterospecific E. formosa was more preferred as a secondary host than the conspecific, E. tricolor, in particular from the prepupal stage onwards. The window of vulnerability, i.e., the duration of the period in which a secondary host is susceptible to hyperparasitism, was largely determined by the occurrence and rate of melanization after the onset of pupation. The duration of a successful hyperparasitization event was longer than one that failed. Superparasitism occurred only once in all cases. The potential effect of autoparasitoids on biological control programs and the consequences for selection and release of an effective, yet ecologically safe agent are discussed.
Amitus fuscipennis, an alternative to the biological control of Trialeurodes vaporariorum by Encarsia formosa?
Vis, R.M.J. de; Lenteren, J.C. van - \ 2008
Bulletin of Insectology 61 (2008)2. - ISSN 1721-8861 - p. 313 - 325.
parasite-host relationship - bemisia-argentifolii - foraging behavior - life-history - tomato - aleyrodidae - greenhouse - hymenoptera - homoptera - platygasteridae
Biological control of Trialeurodes vaporariorum (Homoptera Aleyrodidae) by Amitus fuscipennis (Hymenoptera Platygastridae) with or without Encarsia formosa (Hymenoptera Aphelinidae) was tested in both a glasshouse and a plastic greenhouse during two consecutive production cycles of a beef tomato crop on the Bogotá Plateau in Colombia. The mean temperature was around 16 °C in the plastic greenhouse and around 17 °C in the glasshouse. A. fuscipennis was introduced at a rate of 5 pupae per m2 per week during the first 13 weeks of the first cycle. During the second cycle, 2.5 pupae of both E. formosa and A. fuscipennis per m2 per week were introduced during the first 13 weeks. During the first cycle, control was obtained for 5 months in the plastic greenhouse and 3 months in the glasshouse, after which the population of T. vaporariorum adults increased to a maximum of 50 adults per plant. Parasitism was initially higher than 80% but then decreased to 56% in the plastic greenhouse and to 20% in the glasshouse. During the second cycle, biological control was successful in both greenhouses. Populations of T. vaporariorum were lower than 1.2 adults per plant and parasitism, caused mainly by E. formosa, was near 90% most of the time. Therefore, E. formosa is recommended to keep populations of T. vaporariorum at low levels in unheated greenhouses on the Bogotá Plateau. When high populations of T. vaporariorum are to be expected or control of high-density spots is required, A. fuscipennis could be a beneficial addition to E. formosa.
External and internal elimination of supernumerary larvae in the whitefly parasitoid Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae)
Verde, V. lo; Lenteren, J.C. van; Smid, H.M. ; Jong, P.W. de; Castillo Carillo, C.I. ; Caleca, V. - \ 2008
Biological Control 46 (2008)3. - ISSN 1049-9644 - p. 287 - 292.
interspecific host discrimination - biological-control agents - life-history parameters - bemisia-tabaci - thelytocous eretmocerus - encarsia-formosa - competition - wasps - parthenogenesis - aleyrodidae
The solitary parasitoid Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae) is one of the key biological control agents of the whitefly Bemisia argentifolii Bellows & Perring, also known as B. tabaci (Gennadius) B-biotype (Homoptera: Aleyrodidae). We present new information on its biology, and particularly about larval elimination during the first instar in cases of superparasitism. For the first time, physical elimination of supernumerary larvae was observed, both outside and inside the host. These findings are documented with confocal microscopy images and video recordings. We observed more than 350 B. argentifolii nymphs, parasitized with one, two or more than two larvae. Physical attack took place only when parasitoid eggs were laid in contact with each other. In this case the percentage larval mortality outside the host was significantly higher (45.7%) than in cases of single larvae (12.0%) or larvae hatched under the same host but not in contact with each other (23.3%). These new findings are important in view of a possible horizontal transfer of a parthenogenesis inducing Wolbachia bacterium from a thelytokous to an arrhenotokous strain, with the aim of augmenting the biological control of B. argentifolii.
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.
Geïntegreerde bestrijding in roos onder glas
Pijnakker, J. ; Ramakers, P.M.J. ; Linden, A. van der; Kok, L.W. ; Groot, E.B. de; Holstein, R. van; Garcia Victoria, N. - \ 2008
Bleiswijk : Wageningen UR Glastuinbouw (Rapport / Wageningen UR Glastuinbouw 179) - 50
rosa - rozen - geïntegreerde bestrijding - teelt onder bescherming - plantenplagen - plagenbestrijding - natuurlijke vijanden - amblyseius - phytoseius - aleyrodidae - encarsia - tetranychus - glastuinbouw - rosa - roses - integrated control - protected cultivation - plant pests - pest control - natural enemies - amblyseius - phytoseius - aleyrodidae - encarsia - tetranychus - greenhouse horticulture
Bladmonsters werden verzameld op rozenbedrijven om vast te stellen welke natuurlijke vijanden op deze waardplant voorkomen. Deze inventarisatie werd uitgevoerd op veertig bedrijven, die al dan niet roofmijten hadden geïntroduceerd. In spinthaarden werden Phytoseiulus persimilis, Amblyseius cucumeris, Amblyseiuscalifornicus, Amblyseius barkeri en Amblyseius andesoni gevonden. In wittevlieghaarden troffen we Encarsia formosa en Eretmocerus eremicus aan. Alleen de kaswittevlieg werd waargenomen, geen tabakswittevlieg. Tijdens latere bedrijfsbezoeken werden nog twee andere soorten roofmijten gevonden: Iphiseius degenerans en Amblyseius aurescens. Soortgelijke bemonsteringen werden ook gedaan op buitenrozen door PPO Bomen. Daarbij werden de volgende soorten roofmijten gevonden: Amblyseiuscalifornicus, Amblyseius rademacheri, Kampimodromus aberrans, Amblyseius andersoni en Euseiusfinlandicus. Vooral de twee laatste bieden perspectief voor de bestrijding van spintmijten in roos en werden gekweekt bij PPO Bomen en later ook bij PPO Glas.
Bestrijding van kaswittevlieg in Gerbera
Pijnakker, Juliette - \ 2007
biological control - pest control - ornamental crops - gerbera - predatory mites - aleyrodidae - trials - experimental design - greenhouses - cut flowers - scientific research - greenhouse horticulture
Microsatellites reveal extensive geographical, ecological and genetic contacts between invasive and indigenous whitefly biotypes in an insular environment
Delatte, H. ; David, P. ; Granier, M. ; Lett, J.M. ; Goldbach, R.W. ; Peterschmitt, M. ; Reynaud, B. - \ 2006
Genetical Research 87 (2006)2. - ISSN 0016-6723 - p. 109 - 124.
bemisia-tabaci hemiptera - species complex - competitive displacement - population-structure - dna-polymerase - f-statistics - sweet-potato - b-biotype - aleyrodidae - resistance
Human-mediated bioinvasions provide the opportunity to study the early stages of contact between formerly allopatric, divergent populations of a species. However, when invasive and resident populations are morphologically similar, it may be very difficult to assess their distribution in the field, as well as the extent of ecological overlap and genetic exchanges between invasive and resident populations. We here illustrate the use of data obtained from a set of eight microsatellite markers together with Bayesian clustering methods to document invasions in a group of major tropical pests, Bemisia tabaci, which comprises several morphologically indistinguishable biotypes with different agronomic impacts. We focus on the island of La Réunion, where an invasive biotype (B) has recently been introduced and now interacts with the resident biotype (Ms). The temporal and spatial distribution, host-plant range and genetic structure of both biotypes are investigated. We showed (i) that, without prior information, clustering methods separate two groups of individuals that can safely be identified as the B and Ms biotypes; (ii) that the B biotype has invaded all regions of the island, and showed no signs of genetic founder effect relative to the Ms biotype; (iii) that the B and Ms biotypes coexist in sympatry throughout most of their geographical ranges, although they tend to segregate into different host plants; and finally (iv) that asymmetrical and locus-specific introgression occurs between the two biotypes when they are in syntopy.
Nieuwe predatoren van trips en witte vlieg voor komkommer : opsporen en toetsen van nieuwe roofmijten voor de bestrijding van trips en witte vlieg in komkommer
Messelink, G.J. ; Steenpaal, S.E.F. van; Holstein, R. van; Wensveen, W. van; Groot, E.B. de; Slooten, M.A. van; Ramakers, P.M.J. - \ 2005
Naaldwijk : PPO BU Glastuinbouw (Rapporten PPO BU GTB ) - 83
biologische bestrijding - roofmijten - komkommers - aleyrodidae - trialeurodes vaporariorum - thrips - insectenplagen - glastuinbouw - gewasbescherming - biological control - predatory mites - cucumbers - aleyrodidae - trialeurodes vaporariorum - thrips - insect pests - greenhouse horticulture - plant protection
In komkommer was de soms matige tripsbestrijding met de standaard roofmijt Neoseiulus (Amblyseius) cucumeris aanleiding om nog eens goed te kijken naar de mogelijkheden voor nieuwe roofmijtsoorten. In 2003 werden negen soorten uit de familie Phytoseiidae (bladbewonende roofmijtsoorten) geselecteerd. Drie soorten scoorden significant beter als bestrijder van trips en bereikten significant hogere roofmijtdichtheden dan de standaard roofmijt N. cucumeris. Dit waren de subtropische soorten Typhlodromalus limonicus, Typhlodromips swirskii en Euseius ovalis. Vooral T. limonicus en T. swirskii bereikten opvallend hoge dichtheden wat resulteerde in een respectievelijk 12 en 9 keer zo grote populatie als bij als N. cucumeris. “Nieuwe” inheemse roofmijtsoorten, afkomstig van Cucurbitaceae, scoorden niet beter dan N. cucumeris. De nieuwe roofmijt T. swirskii was ook op gewasniveau een significant betere bestrijder van trips dan N. cucumeris. Een vergelijkingsproef liet bovendien zien dat T. swirskii in staat is om een populatie N. cucumeris volledig te verdringen.
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.
Selection of Bemisia nymphal stages for oviposition or feeding, and host-handling times of arrhenotokous and thelytokous Eretmocerus mundus and arrhenotokous E. eremicus
Ardeh, M.J. ; Jong, P.W. de; Lenteren, J.C. van - \ 2005
BioControl 50 (2005)3. - ISSN 1386-6141 - p. 449 - 463.
encarsia-formosa hymenoptera - trialeurodes-vaporariorum homoptera - biological-control agents - life-history parameters - amitus-fuscipennis - aphelinid parasitoids - foraging behavior - aleyrodidae - tabaci - strategies
Host-handling behavior is an important aspect of parasitoid foraging behavior. When a parasitoid encounters a potential host, the handling behavior starts with the evaluation of the host and continues if the host has been judged acceptable. Host handling is usually terminated after egg laying or host feeding and host marking. Host-handling behavior of an arrhenotokous population of two Eretmocerus species, E. mundus Mercet and E. eremicus Rose and Zolnerowich, along with a thelytokous population of E. mundus were compared under laboratory conditions. Several elements of host-handling behavior, including encountering, ascending, turning on host, descending, preening, egg laying, and host feeding were recorded. There were no correlations among the durations of these phases across parasitoid populations/species or host nymphal instars. Duration of different phases of host-handling behavior showed only slight and sometimes significant differences between different Eretmoceruspopulations/species. The actual laying of the egg had the longest duration of all host-handling behaviors, and was longer on third nymphal instars than on younger ones. Females of the three populations/species accepted the first three nymphal stages either for egg laying or for host feeding. Females spent a lot of time to make wounds in the host when preparing for host feeding, and eventually killed the host. The implications of these findings for the use of the different Eretmoceruspopulations/species in biological control are discussed
Inter- and intraspecific effects of volatile and nonvolatile sex pheromones on males, mating behavior and hybridization in Eretmocerus mundus and E. eremicus (Hymenoptera: Aphelinidae)
Ardeh, M.J. ; Jong, P.W. de; Loomans, A.J.M. ; Lenteren, J.C. van - \ 2004
Journal of Insect Behavior 17 (2004)15. - ISSN 0892-7553 - p. 745 - 759.
nr-californicus hymenoptera - tabaci complex homoptera - biological-control - bemisia-tabaci - walker hymenoptera - aleyrodidae - wasps - ichneumonidae - parasitoids - populations
Eretmocerus species (Hym. Aphelinidae) are solitary parasitoids of Bemisia tabaci (Gennadius). Mate finding and mating behavior of two species, E. mundus and E. eremicus, were studied under laboratory conditions. We used three populations of Eretmocerus: typical arrhenotokous populations of E. eremicus ( from USA) and E. mundus ( from Spain), and an atypical thelytokous population of E. mundus ( from Australia). We studied the intra- and interspecific responses of males to volatile and nonvolatile components of the female sex pheromones, mating behavior, and hybridization between populations and species. In both arrhenotokous populations, males reacted to volatile pheromones by walking toward conspecific virgin females. Males also reacted to nonvolatile pheromones by spending more time on and around patches on leaves of poinsettia plants that had been exposed to virgin females. Males of E. eremicus showed the same reaction to the nonvolatile sex pheromone of E. mundus females, but E. mundus males did not show any reaction to the nonvolatile sex pheromone of E. eremicus. There was no response of males of both species to thelytokous females of E. mundus. In both species three phases were distinguished in the mating behavior: premating, mating, and postmating. The duration of the phases differed between the three populations. Successful copulation between the two Eretmocerus species did not occur. In contrast, we recorded some successful copulations between Australian males and Spanish females of E. mundus, but they did not produce any hybrid females.
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.