Larval development and voracity of Eupeodes americanus (Diptera: Syrphidae): comparison of the focal prey Aphis gossypii (Hemiptera: Aphididae) and the banker prey Rhopalosiphum padi (Hemiptera: Aphididae)

ABSTRACT: Unlike European species, the potential of Nearctic syrphids as biological control agents is still poorly studied. However, the American hoverfly, Eupeodes americanus (Wiedemann), has recently demonstrated promising traits as a biocontrol agent, notably against the foxglove aphid, Aulacorthum solani Kaltenbach, on pepper. The present study aims to extend our knowledge of the American hoverfly by evaluating its potential as a biocontrol agent in a banker plant system against the melon aphid, Aphis gossypii Glover, in a greenhouse cucumber crop. The preimaginal development and voracity of E. americanus were compared when preying upon the focal prey/pest (A. gossypii) or the banker prey (bird cherry-oat aphid, Rhopalosiphum padi L.) by daily observations of larvae from egg to adult. Preimaginal development time, survival rate, and occurrence of deformation were similar on both prey species. The weight of third instar and pupae, however, was higher for larvae that fed on the banker prey. The ad libitum voracity of the syrphid larvae was generally very high and did not significantly differ between prey species, except for the third-instar larvae which consumed more focal prey. Results suggest that a banker plant system involving the bird cherry-oat aphid may be a promising tactic for utilizing E. americanus for melon aphid biocontrol.info:eu-repo/semantics/publishedVersio

The right banker plant for the right application: Comparison of three candidates for aphid biocontrol, barley (Hordeum vulgareL.), corn (Zea maysL.), and finger millet (Eleusine coracana (L.) Gaertn)

BACKGROUND In temperate regions, aphid biological control in greenhouses is mostly achieved by the regular release of biocontrol agents. Due to the rapid growth rate of the aphid population, biocontrol agents must be released frequently in order to be present before pest outbreaks and to act rapidly to prevent exceeding the economic threshold. Banker plants reduce these numerous releases by providing natural enemies with a high-quality environment to develop and reproduce. Optimally, banker plants should be easy to produce, resistant to environmental conditions, provide a large amount of suitable banker prey in order to produce a high number of biocontrol agents, and resist the herbivory pressure of the banker prey. The present study aimed to compare the value of three banker plant candidates of the Poaceae family under laboratory and greenhouse conditions: barley (Hordeum vulgare L.), finger millet (Eleusine coracana (L.) Gaertn), and corn (Zea mays L.). RESULTS Our results show that the three plants were suitable for different contexts. Finger millet yielded the biggest fresh plant biomass, supported the highest load of banker prey, and resisted aphid feeding longer than the other plant species. Corn was the cheapest to produce, and barley was the fastest to grow. CONCLUSIONS Overall, finger millet could be more fitted for long crop cycles, pests with rapid population growth rates, and voracious or fast-reproducing biocontrol agents. Meanwhile, barley and corn may be better suited for rapid crop cycles, pests with slow population growth rates, and biocontrol agents that are not too voracious or have low reproductive rates. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.info:eu-repo/semantics/publishedVersio

Morphological determination of the larval instars of Eupeodes americanus (Diptera: Syrphidae)

In North America, the potential of the American hoverfly Eupeodes americanus (Wiedemann, 1830) (Diptera: Syrphidae) as a biocontrol agent has been demonstrated, particularly against the foxglove aphid Aulacorthum solani Kaltenbach, 1843 (Hemiptera: Aphididae). Since no information is available to distinguish the larval instars of this species, the present study used the semi-continuous observation (time-lapse photography and stereo microscope) of the three larval stages to build a table of morphological traits and a dichotomic key for discriminating the larval instars by observation under stereo microscope. Discriminating traits are black hairs at first instar and fused posterior breathing tubes at third instar.This study was funded by the Ministère de l’Agriculture, des Pêcheries et de l’Alimentation du Québec (MAPAQ), following the program Prime-Vert 18-009-UQAM and by a CRSNG discovery grant to Eric Lucas. Funding was also provided by Agriculture and AgriFood Canada through the Canadian Agricultural Partnership, underthe AgriScience Program.info:eu-repo/semantics/publishedVersio

Morphological determination of the larval instars of Eupeodes americanus (Diptera: Syrphidae)

In North America, the potential of the American hoverfly Eupeodes americanus (Wiedemann, 1830) (Diptera: Syrphidae) as a biocontrol agent has been demonstrated, particularly against the foxglove aphid Aulacorthum solani Kaltenbach, 1843 (Hemiptera: Aphididae). Since no information is available to distinguish the larval instars of this species, the present study used the semi-continuous observation (time-lapse photography and stereo microscope) of the three larval stages to build a table of morphological traits and a dichotomic key for discriminating the larval instars by observation under stereo microscope. Discriminating traits are black hairs at first instar and fused posterior breathing tubes at third instar.En Amérique du Nord, le potentiel du syrphe d’Amérique Eupeodes americanus (Wiedemann, 1830) (Diptera: Syrphidae) comme agent de lutte biologique a été démontré, notamment contre le puceron de la digitale Aulacorthum solani Kaltenbach, 1843 (Hemiptera: Aphididae). Aucune information n’étant disponible pour distinguer macroscopiquement les stades larvaires de cette espèce, la présente étude a utilisé l’observation semi-continue (photographie time-lapse et observation à la loupe binoculaire) des trois stades larvaires pour construire un tableau de traits morphologiques et une clé dichotomique pour discriminer les stades larvaires par observation à la loupe binoculaire. Les traits discriminants sont la présence de poils noirs au premier stade et la fusion des tubes respiratoires postérieurs au troisième stade