Abundanz von Getreideaphiden im Winterweizen in Abhängigkeit von Bewirtschaftunggssystemen mit unterschiedlicher Stickstoff-Intensität

Summary

The reorganisation from conventional to organic farming practice on a farm located in Northern Germany was accompanied in a long term monitoring to survey the abun-dances of cereal aphids and their natural enemies in winter wheat. The research project focuses on the interactions of host plant and aphids in ecological crop rotation systems differing in their amount of legumes (nitrogen intensive, nitrogen extensive system). Additionally manure treated winter wheat plots established in both ecological crop rota-tion systems were investigated. For comparison the abundance of aphids in conventional farming systems with winter wheat fields nearby were also monitored. The results indi-cate that within the triannual investigation period, aphids significantly varied both in abundance and species composition with regard to the various nitrogen levels. The ear dwelling species Sitobion avenae exhibited the highest damage potential and was sub-stantially less influenced by the extensive conditions of organic farming practice in con-trast to Metopolophium dirhodum and Rhopalosiphum padi sucking on the flag leaves and on lower leaf parts, respectively.