Phenology, basic biology and parasitism of Microgaster tibialis (Hymenoptera, Braconidae), a parasitoid of the European corn borer, Ostrinia nubilalis, in Central Europe

Phenology, bionomics and parasitism of Microgaster tibialis, a parasitoid o f the European corn borer, Ostrinia nubilalis, was studied in four regions of Central Europe in 1993-1995. Regular parasitism of O. nubilalis larvae ( 1.83-2.95%) was observed at Blatnice in Moravia (eastern part of the Czech Republic). Parasitoid cocoons were also found in SW Slovakia and E Slovakia during 1994-1995 and at Wroclaw (SW Poland) in 1994. These records are the first from Moravia, Slovakia and from Poland. The findings suggest that M. tibialis generally pupate at the end of September and at the beginning of October in Central Europe. Parasitoid adults emerged during April. Developm ent threshold temperatures for 50% adult emergence was 2 degrees C, the cor responding thermal constants were 294.6-311.0 Celsius degree-days. M. tibia lis has probably two generations a year, the first one parasitizing on an a lternate host.