Trichogramma nubilale (Hymenoptera: Trichogrammatidae) Field Releases in Corn and a Hypothetical Model for Control of European Corn Borer (Lepidoptera: Pyralidae)

Abstract

Maximum emergence of Trichogramma nubilale Ertle and Davis was obtained from parasitized European corn borer (ECB), Ostrinia nubilalis (Hubner), eggs that were laboratory incubated for a minimum of 7 days before placement in field-release containers. A release rate of 300 females per day per 0.3719 ha resulted in 40% parasitism of first-brood ECB egg masses. It is calculated that a release rate of ca. 2,400 and 12,000 females per day per ha would be needed to achieve 80% parasitism (i.e., control) of first and second brood, respectively. A hypothetical T. nubilale release model for control of ECB in corn is presented that incorporates changes (i.e., increases) in release rates relative to increases in the parasitoid searching area, namely, leaf surface.