Environmental Entomology (2003) 32, 1131-1138

Fred R. Musser and Anthony M. Shelton (2003)
Predation of Ostrinia nubilalis (Lepidoptera: Crambidae) eggs in sweet corn by generalist predators and the impact of alternative foods
Environmental Entomology 32 (5), 1131-1138
Abstract: 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.
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Database assignments for author(s): Fred R. Musser, Anthony M. Shelton

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution
environment/habitat manipulation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Ostrinia nubilalis	Maize/corn (Zea mays)	U.S.A. (NE)
Harmonia axyridis (predator)	Ostrinia nubilalis	Maize/corn (Zea mays)	U.S.A. (NE)
Coleomegilla maculata (predator)	Ostrinia nubilalis	Maize/corn (Zea mays)	U.S.A. (NE)
Orius insidiosus (predator)	Ostrinia nubilalis	Maize/corn (Zea mays)	U.S.A. (NE)