Abundance and prevalence of Aphidius avenae (Hymenoptera: Braconidae: Aphidiinae) in Chile

Abstract

During the samplings described here, Aphidius avenae (=picipes) (Haliday, 1834) was collected. This species has been reported in Chile but has never been studied in terms of its relative abundance and prevalence in central and southern Chile by using classical or molecular methods. The composition of the parasitoid assemblages on several cereal aphid hosts was examined for three seasons in agricultural landscapes. In this note, we describe the prevalence of this parasitoid species in cereal aphids and other aphid hosts and discuss the abundance of this parasitoid compared to other aphid parasitoids and the probable origins of this important aphid parasitoid species in Chile. The results indicate that A. avenae has a low prevalence compared to other main parasitoids such as Aphidius ervi (Haliday) and that it has been found parasitizing the grain aphid ( Sitobion avenae (Fabricius)) and the bird cherry-oat aphid ( Rhopalosiphum padi (Linnaeus)) in wheat and the foxglove aphid ( Aulacorthum solani (Kaltenbach)) in tomato. Although the introduction of A. avenae in Chile as a biological agent in 1992 was not successful, we here confirm the presence of this aphid parasitoid wasp in Chile and discuss the factors that could explain the low prevalence of this parasitoid species in the country.