The flat grain beetle (FGB) species Cryptolestes ferrugineus, C. pusillus, C. pusilloides and C. turcicus are major stored-product pests worldwide, of which the first three are present in Australia. C. ferrugineus is also a species with high phosphine resistance status in various countries. Morphological identification of Cryptolestes species is difficult and represents an additional barrier to effective management of phosphine resistance in FGBs.