In studies conducted in 1999 and 2000 at two different localities, Flaeming and Magdeburger Bordae in Germany, new information is provided on small cereal aphids, Sitobion avenae (F.), Metopolophium dirhodum (Walker), and Rhopalosiphum padi L., parasitoids in winter wheat. Species composition, relative abundance, hosts, and location effects have been investigated. In total, eight species of primary parasitoids were discovered: Aphidius colemani Viereck, A. ervi Haliday, A. picipes (Nees), A. rhopalosiphi DeStefani Perez, A. uzebekistanicus Luzhetzki, Ephedrus plagiator (Nees), Praon gallicum Starż, and P. volucre (Haliday). The predominant parasitoids were A. rhopalosiphi and A. uzebekistanicus on M. dirhodum and A. uzebekistanicus on S. avenae. The abundance of parasitoid species was higher at Magdeburger Bordae than at Flaeming. Aphidius colemani has been used mostly in the greenhouse in central Europe and also released in the field in Czech Republic for the control of cereal aphids. Surprisingly, however, this parasite has been discovered attacking cereal aphids in the open field on winter wheat in Germany. This indicates the successful establishment of the parasite even far from its release areas in Czech Republic. Three species of hyperparasitoids were also recorded mostly emerged from the mummies of M. dirhodum. This study provides baseline information essential for assessing future changes in aphid parasitoid species dynamics and possible introduction of exotic species in Germany.
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA