Susceptibility to ivermectin of larvae of Australian sheep blowfly, Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae)

Abstract A toxicological survey of 74 Australian field populations of Lucilia cuprina was used to describe the range of responses of first‐instar larvae to ivermectin in an in‐vitro bioassay. All populations were susceptible with only a 4‐fold difference between the least and most tolerant populations at the LC50 level. The frequency distribution of LC50s was normally distributed around the mean of 9.8 μg/L. The data recorded will provide a susceptible baseline for resistance monitoring when ivermectin is again released for the control of flystrike on sheep.