A new banker plant system for supporting Aphidius ervi

Abstract: Aphidius ervi is a parasitoid of Macrosiphum euphorbiae and Acyrthosiphon solani, both important aphid pests in greenhouse crops. Some greenhouse growers want to support a continuous supply of A. ervi in their greenhouses with aphid banker plants. Two popular systems have been Rhopalosiphum padi with Aphidius colemani and Sitobion avenae with A. ervi. However, a roadblock to the use of both systems together was that R. padi and A. colemani would contaminate and out compete S. avenae with the result that the A. ervi banker system would die out. We set out to find a banker plant system that could function without interference from R. padi and A. colemani in the same greenhouse. We demonstrated that fava beans would support pea aphids, Acyrthosiphon pisum, which in turn produces robust A. ervi. The pea aphid is compatible with many crops as a banker aphid because it colonizes only certain legumes, including lupines, peas, and sweet peas. Successes and difficulties with the system are reviewed.