Parasitism rates in European corn borer (Lepidoptera : Crambidae) larvae collected from six maize hybrids

The parasitoid complex and level of parasitism of European corn borer, Ostr inia nubilalis (Hubner), larvae in six maize, Zea mays L., hybrids was dete rmined in Nebraska during 1995 and 1996. Three parasitoids, Eriborus terebr ans (Gravenhorst), Macrocentrus grandii Goidanich, and Lixophaga sp., were reared from field-collected European corn borer larvae. Larvae collected fr om Hoegemeyer 2626 exhibited the highest percentage parasitism for the 1995 first generation in Lancaster (37.2%) and Dixon (28.6%) counties. No signi ficant differences were identified for the 1995 second generation at both s ites because of reduced sample size and high larval mortality caused by nat urally-occurring entomopathogens. During 1996, there were several significa nt differences in percentage parasitism of larvae collected from the hybrid s. Larvae collected from Northrup King N7070 exhibited the highest first-ge neration parasitism (23.8%), while larvae collected from Hoegemeyer 1125W e xhibited the highest second-generation parasitism (46.0%) in Dixon Co. In L ancaster Co., parasitism of first-generation larvae collected from Hoegemey er 1125W (10.3%) was only significantly greater than parasitism of larvae c ollected from Hoegemeyer 2626 (1.1%). Results indicate that European corn b orer larval parasitism is significantly affected by the maize hybrid plante d in the field; however, differences may vary among years and generations a s environmental factors affect the maize phenology.