Laboratory and field investigations were carried out in South Dakota on the suitability of a range of cereals and grasses as food-plants for the root-feeding larvae of Diabrotica virgifera Lec, which have not previously been reported from plants other than maize. Of 22 species grown from seeds on agar [cf. RAE A 31 501], nine permitted development to the second larval instar, and some of these were investigated further. Adult emergence from larvae fed on maize and on Minier and Selkirk wheat was 55, 18 and 3%, respectively, the rates of development being similar on all three. Adults were reared in the field from larvae fed on Setaria viridis, S. lutescens, Minier wheat, Omugi barley and Agropyrum intermedium, but the data did not permit comparison of the relative suitability of these plants.