The correspondence between five primary aphid parasitoids (Hymenoptera: Braconidae, Aphelinidae) and their secondary parasitoids (Hymenoptera: Figitidae, Encyrtidae, Megaspilidae and Pteromalidae)
摘要
Occurrences of secondary parasitoids on five primary aphid parasitoids were surveyed using traps with parasitised aphids on potted plants in two field experiments to clarify their risk to banker-plant systems. In Field Experiment 1, from 2010 to 2012, three primary parasitoids, Aphidius gifuensis Ashmead, Diaeretiella rapae (M’Intosh), and Ephedrus nacheri Quilis (Hymenoptera: Braconidae: Aphidiinae), were prepared on Myzus persicae (Sulzer) (Hemiptera: Aphididae) on potted komatsuna plants or Rhopalosiphum maidis (Fitch) on potted barley or sorghum plants and exposed to the field for 7 days every 2 weeks from spring to autumn. In Field Experiment 2, in 2013, Aphidius colemani Viereck (Hymenoptera: Braconidae: Aphidiinae), E. nacheri, and Aphelinus varipes (Förster) (Hymenoptera: Aphelinidae) were prepared on M. persicae on potted komatsuna plants and exposed in the same manner. Mummified aphids were collected and emerged adults were identified. The following secondary parasitoids were identified: three species of Figitidae: Phaenoglyphis villosa (Hartig), Alloxysta victrix (Westwood), Alloxysta brevis (Thomson) group, one species of Encyrtidae: Syrphophagus tachikawai (Hoffer), two species of Megaspilidae: Dendrocerus laticeps (Hedicke) and Dendrocerus carpenteri (Curtis) and two species of Pteromalidae: Asaphes suspensus (Nees), and Pachyneuron aphidis (Bouché). Alloxysta victrix occurred on A. gifuensis and A. colemani, but was not detected on D. rapae, E. nacheri or A. varipes. Syrphophagus tachikawai occurred on A. gifuensis, A. colemani, D. rapae, and A. varipes in summer and autumn, but seldom appeared on E. nacheri. Pachyneuron aphidis primarily occurred in summer. This information will be useful for constructing banker-plant systems to avoid the risk from secondary parasitoids.