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Turlings, Ted

Nom
Turlings, Ted
Affiliation principale
Fonction
Professeur ordinaire
Email
ted.turlings@unine.ch
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https://libra.unine.ch/handle/123456789/330

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  • Publication
    Accès libre
    Parasitism of non-target lepidoptera by mass released Trichogramma brassicae and its implication for the larval parasitoid Lydella thompsoni
    (2004)
    Kuske, Stefan
    ;
    Babendreier, Dirk
    ;
    Edwards, Peter
    ;
    Turlings, Ted 
    ;
    Bigler, Franz
    The release of high numbers of the eggparasitoid Trichogramma brassicae Bezd.(Hym. Trichogrammatidae) to control the European corn borer (ECB), Ostrinianubilalis Hb. (Lep.: Crambidae) in maize hasraised concerns about potential negativeeffects on native natural enemies. The nativelarval parasitoid Lydella thompsoni Herting (Dipt.: Tachinidae) is the most frequent and important ECB parasitoid insouthern Switzerland and can achieve highparasitism rates. Its first generation emerges too early to find ECB larvae and must rely onalternative hosts living in natural habitats close to maize fields. Inundative releases of T. brassicae coincide with the oviposition period of the alternative hosts ofthe tachinid. T. brassicae moving out of release fields may attack and diminish the population of these hosts, creating abottleneck situation for L. thompsoni in the subsequent spring. Laboratory hostspecificity tests showed that the tachinid's two most abundant spring hosts Archanarageminipuncta Haworth (1809) (Lep.: Noctuidae)and Chilo phragmitellus Hübner (1805)(Lep.: Crambidae) are successfully parasitisedby T. brassicae females in no-choice situations. Our extensive field surveys, however, showed that the two tested springhosts escape parasitism since their eggs are well hidden or not attractive. Negative effects of inundative releases of T.brassicae on the native tachinid fly L. thompsoni, such as population density reduction, displacement, or local extinction, are very unlikely.
  • Publication
    Métadonnées seulement
    Dispersal and persistence of mass released Trichogramma brassicae (Hymenoptera : Trichogrammatidae) in non-target habitats
    (2003)
    Kuske, Stefan
    ;
    Widmer, Franco
    ;
    Edwards, Peter
    ;
    Turlings, Ted 
    ;
    Babendreier, Dirk
    ;
    Bigler, Franz
    Field studies were carried out to evaluate whether inundative releases of Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae) against the European corn borer, Ostrinia nubilalis Hubner (Lepidoptera: Crambidae), can have negative effects on the indigenous arthropod fauna in adjacent non-target habitats. Emigration of released T brassicae from maize fields into non-target habitats was monitored, and its persistence in non-target habitats was assessed throughout the season. For this purpose, sticky traps were installed on metal sticks along transects from the inside of T brassicae treated maize fields into sown wildflower strips and a natural common reed stand. In addition, cards with host eggs were used to monitor Trichogramma within potential overwintering sites. Although the highest numbers of released parasitoids were trapped within maize, a considerable amount of T. brassicae moved into non-target habitats. We found a significant transient increase of T. brassicae in both wildflower strips and reeds and no consistent decrease in numbers of trapped wasps up to 40 m from the maize field borders, when monitored directly following mass releases. Indigenous Trichogramma species were present both in the wildflower strip and reeds, and T. brassicae represented only a minor part of the overall Trichogramma population therein, except for a few days after release. However, a few T brassicae persisted in non-target habitats throughout the season and were still present prior to releases in the subsequent year. These low numbers are not expected to seriously affect populations of native Trichogramma or non-target host species. (C) 2003 Elsevier Science (USA). All rights reserved.
  • Publication
    Métadonnées seulement
    The induction of volatile emissions in maize by three herbivore species with different feeding habits: Possible consequences for their natural enemies
    (: Academic Press Inc, 1998)
    Turlings, Ted 
    ;
    Bernasconi, Marco
    ;
    Bertossa, Rinaldo
    ;
    Bigler, Franz
    ;
    Caloz, Genevieve
    ;
    Dorn, Silvia
    In order to find their prey natural enemies of herbivores often make effective use of plant volatiles that are emitted by plants on which the herbivores have been feeding. The phenomenon of herbivore-induced emissions of attractants has been well investigated for mite-plant interactions and for interactions between leaf feeding caterpillars and plants. Herbivore-induced emissions of chemical signals appear to be common in plants, but little is known about induction by herbivores that have different feeding habits. We obtained more knowledge on this by comparing the volatile emissions induced in maize plants by a folivorous caterpillar (Spodoptera littoralis), a stemborer (Ostrinia nubilalis), and an aphid (Rhopalosiphum maidis). As controls we also measured the emissions of healthy, undamaged plants and plants that were mechanically damaged and then treated with caterpillar regurgitate. Volatiles were collected twice daily for 2 h over a 3-day period after initial infestation or mechanical damage. Quantitatively, the plants infested with S. littoralis emitted by far the most. Their emissions started several hours after initial damage, lasted for the 3 days, and were the highest on the third day. The volatile profile was the same for the regurgitate-treated plants, but here the emissions dropped rapidly after the first day. The plants infested by O. nubilalis emitted the same blend of volatiles, but in much lower quantities, In addition to the known induced maize volatiles, the Ostrinia-damaged plants emitted some highly volatile, still unidentified compounds, which may be specific for the frass of this insect or emitted from the damaged plant stem. The aphids induced no measurable emissions of volatiles in the maize, even after heavy infestation. This is perhaps because several aphids, including R. maidis, barely damage the plant cells, and may not trigger a plant response. These findings suggest that induction of volatiles is the result of cell tissue damage, particularly to the leaves of the plant. This should have consequences also for the search strategies employed by the natural enemies of the respective herbivores, It can be expected that enemies of stemborers use some highly volatile compounds in addition to the known induced compounds. Natural enemies of some aphids may have to resort to other foraging cues, as the plant appears to provide them with no or very little olfactory information. (C) 1998 Academic Press.