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Predation of Ostrinia nubilalis (Lepidoptera: Crambidae) Eggs in Sweet Corn by Generalist Predators and the Impact of Alternative Foods

Musser, Fred R. ; Shelton, Anthony M.

In: Environmental Entomology, 2003, vol. 32, no. 5, p. 1131-1138

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    Titre
    • Predation of Ostrinia nubilalis (Lepidoptera: Crambidae) Eggs in Sweet Corn by Generalist Predators and the Impact of Alternative Foods
    Auteur
    • Musser, Fred R.. Department of Entomology, Cornell University, New York State Agricultural Experiment Station, 630 W. North Street, Geneva, New York 14456
    • Shelton, Anthony M.. Department of Entomology, Cornell University, New York State Agricultural Experiment Station, 630 W. North Street, Geneva, New York 14456
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Environmental Entomology, 2003, vol. 32, no. 5, p. 1131-1138. Oxford University Press
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:294100
    Summary
    Generalist predators are common in most agricultural cropping systems. However, pest control from these predators is often overlooked as a component of integrated pest management (IPM) because the extent of predation is generally unknown and difficult to assess. In western New York sweet corn (Zea mays L.), the primary predators are Orius insidiosus (Say), Coleomegilla maculata (DeGeer), and Harmonia axyridis (Pallas). European corn borer [Ostrinia nubilalis (Hübner)] is the primary insect pest. The objectives of this study were to compare O. nubilalis egg predation rates for these three species and to understand how egg predation by these predators is affected by the availability of alternative food. Laboratory data indicate that all three predators feed on O. nubilalis eggs. C. maculata consumed more eggs than H. axyridis or O. insidiosus. Immatures of C. maculata and O. insidiosus readily completed development on a diet of O. nubilalis eggs, but H. axyridis larvae could not complete development on this diet. The presence of corn leaf aphids [Rhopalosiphum maidis (Fitch)] and corn pollen reduced egg predation per insect for some stage of all species. The reduction in O. nubilalis egg predation associated with the presence of aphids was confirmed in field cage studies and was similar among the coccinellid populations tested. Field studies comparing aphids, predator populations, and O. nubilalis egg predation show that reduced egg predation per insect more than offsets the higher populations encountered when aphids and pollen are numerous, resulting in less biological control of O. nubilalis when alternative foods are available