Ward, S.E.Umina, P.A.Parry, H.Balfour-Cunningham, A.Cheng, X.Heddle, T.Holloway, J.C.Langley, C.Severtson, D.Van Helden, M.Hoffmann, A.A.2025-07-112025-07-112022Pest Management Science, 2022; 78(8):3596-36071526-498X1526-4998https://hdl.handle.net/2440/145875Background: Estimatingparasitoid abundance in the field can be difficult, evenmore sowhen attempting to quantify parasitism rates andtheecosystemserviceofbiologicalcontrol thatparasitoidscanprovide.Tounderstandhow‘fieldobserved’parasitismrates(in-field mummycounts)of thegreenpeach aphid,Myzus persicae (Sulzer) (Hemiptera:Aphididae) translate to ‘laboratory observed’ parasitism rates (laboratory-reared parasitoid counts), field workwas undertaken in Australian canola fields, over thewinter growing season. Results: Overall, laboratory observed parasitism was on average 2.4 times higher than field observed parasitism, with rates an average of four-fold higher in fields from South Australia. Total field observed and laboratory observed parasitism rates (OPRs) of M. persicae varied considerably across regions, but less so among fields within regions. As crop growth stage progressed, the incidence of field observed mummies increased. The incidence of total parasitoids reared also increased with crop growth stage, averaging 3.4% during flowering and reaching 14.4% during podding/senescing. Although there was a greater diversity of reared parasitoid species at later crop growth stages, the laboratory OPR was unaffected by parasitoid species. Diaeretiella rapae was the most commonly reared parasitoid, increasing in absolute abundance with crop growth stage. Conclusion: These findings indicate that field mummy counts alone do not provide a clear representation of parasitism within canola fields.en© 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Aphididae; Aphidiinae; biological control; hymenopteraAnimalsAphidsHymenopteraWaspsBrassica napusEcosystemPest Control, BiologicalAustraliaJournal article10.1002/ps.70022024-04-23615079Heddle, T. [0000-0002-6621-6889]Van Helden, M. [0000-0002-1955-5976]