Evaluating biocontrol potential of 6 parasitoid species (Hymenoptera) on apple and cherry aphids (Hemiptera: Aphididae) using no-choice bioassays

European apple and cherry production depend on plant protection substances, but the variety of available options is continuously declining. Consequently, there is a need for alternative pest control strategies in orchards. An alternative method is the use of biocontrol agents, such as parasitoids. A range of parasitoid species is commercially available and a well-recognized strategy against aphid pests in protected crops. However, the efficacy of these species against apple and cherry aphid pests is still unexplored. Therefore, we conducted no-choice bioassays to assess the compatibility of 6 parasitoid species-Aphelinus abdominalis Dalman (Hymenoptera: Aphelinidae), Aphidius colemani Viereck (Hymenoptera: Braconidae), Aphidius ervi Haliday (Hymenoptera: Braconidae), Aphidius matricariae Haliday (Hymenoptera: Braconidae), Ephedrus cerasicola Stary (Hymenoptera: Braconidae), and Praon volucre Haliday (Hymenoptera: Braconidae)-against 3 target aphid species: Myzus cerasi Fabricius (Hemiptera: Aphididae), Aphis pomi De Geer (Hemiptera: Aphididae), and Dysaphis plantaginea Passerini (Hemiptera: Aphididae). The assays were conducted under greenhouse conditions on host tree cuttings (M. cerasi) or under controlled climate chamber conditions on saplings (A. pomi, D. plantaginea) with laboratory-reared aphid colonies. For each parasitoid species, the aphid colonies were inoculated with 5 to 10 females for a minimum of 72 h. The resulting parasitism rate was evaluated after 14 d. Our experiments show that host compatibility varies considerably between aphid species. Among the parasitoids tested, P. volucre and Aphi. matricariae emerged as the most consistent and effective species across all hosts. This suggests ecological compatibility and indicates that these 2 species are promising candidates for biological control in fruit orchards.