Abstract
We evaluated the egg parasitoid Trichogramma ostriniae (Hymenoptera: Trichogrammatidae) to control European corn borer [Lepidoptera: Crambidae: Ostrinia nubilalis (Hubner)] in Weld corn in 2001 and 2002. Inoculative releases of 75,000 T. ostriniae/ha occurred in New York and Virginia in 5–10 cornWelds per state when corn was at mid-whorl. Incidence of egg mass parasitism, number of stalk tunnels, incidence of ear damage, and whole-plant yield were evaluated. Parasitism of European corn borer egg masses ranged from 0 to 75% in release plots and was greater in release plots than in control plots. Individual comparisons between paired release and control plots showed no reductions in either stalk or ear damage. However, when data were combined across both years and Welds, stalk and ear damage were signiWcantly reduced in New York. In Virginia, no signiWcant diVerences were detected using data obtained from one year. There were no diVerences in yield between release and control plots. Low densities of European corn borer, drought conditions in 1 year, and a larger plant canopy in Weld corn are possible reasons why T. ostriniae releases provided less control than has been observed in previous trials in sweet corn. Additional research focused on improved timing and frequency and number of releases is warranted.
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