A survey was conducted in 1977-78 to determine the level of insecticide resistance in field strains of Lucilia cuprina from a wide area of Queensland. Discriminating dose data showed that all 19 strains tested were resistant to diazinon, dichlofenthion, fenthion-ethyl and chlorfenvinphos, but resistance factors in all strains were low, the highest being 18.9 for diazinon. Six strains showed no resistance to butacarb. A strain collected in 1967 and selected with diazinon for 117 generations, attained resistance factors of organophosphorus compounds far higher than those of the present field strains.
