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Assays with Commercially Produced Trichogramma (Hymenoptera: Trichogrammatidae) To Determine Suitability for Obliquebanded Leafroller (Lepidoptera: Tortricidae) Control

Lawson, D. S. ; Nyrop, J. P. ; Reissig, W. H.

In: Environmental Entomology, 1997, vol. 26, no. 3, p. 684-693

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    Title
    • Assays with Commercially Produced Trichogramma (Hymenoptera: Trichogrammatidae) To Determine Suitability for Obliquebanded Leafroller (Lepidoptera: Tortricidae) Control
    Author
    • Lawson, D. S.. Department of Entomology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456
    • Nyrop, J. P.. Department of Entomology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456
    • Reissig, W. H.. Department of Entomology, Cornell University, New York State Agricultural Experiment Station, Geneva, NY 14456
    Document Type
    • Postprint
    Language
    • English
    Published in
    • Environmental Entomology, 1997, vol. 26, no. 3, p. 684-693. Oxford University Press
    Other Version
    OAI-PMH Identifier
    • oai:doc.rero.ch:292244
    Summary
    Laboratory assays were used to compare the ability of commercially produced Trichogramma spp. to parasitize eggs of the obliquebanded leafroller, Choristoneura rosaceana (Harris), in the laboratory and field. Trichogramma platneri Nagarkatti parasitized more obliquebanded leafroller eggs per egg mass than did Trichogramma pretiosum Riley or Trichogramma minutum Riley produced by either of 2 insectaries. T. minutum produced at 1 insectary caused significantly more host mortality by host feeding and repiercing than by parasitism. Variation in parasitoid performance from different insectaries and among shipments from the same insectary was common. Young egg masses were more heavily parasitized than old egg masses. Parasitism increased as the number of conspecific female Trichogramma spp. placed on the same host increased, but the number of eggs parasitized per female decreased. Exposure of host egg masses to female Trichogramma spp. prevented additional oviposition in the same egg mass by conspecific, ovipositionally experienced females but had no effect on parasitism by conspecific, ovipositionally naive females. The method used to attach sentinel egg masses to foliage influenced parasitism rates. Moistening the leaf with water and adhering the egg mass to the moistened leaf had the least impact. Inundative releases of Trichogramma spp. into an apple orchard paralleled laboratory assays by showing greater parasitism of obliquebanded leafroller egg masses by T. platneri than with T. minutum. However, extreme differences observed in field performance between the 2 species was not predicted from the assays