Crimson rosellas forage in trees, bushes, and on the ground for the fruit, seeds, nectar, berries, and nuts of a wide variety of plants, including members of the Myrtaceae, Asteraceae, and Rosaceae families. Despite feeding on fruits and seeds, rosellas are not useful to the plants as seed-spreaders, because they crush and destroy the seeds in the process of eating them. Their diet often puts them at odds with farmers whose fruit and grain harvests can be damaged by the birds, which has resulted in large numbers of rosellas being shot in the past. Adelaide rosellas are known to feed on dormant cherry flower buds. Rosellas will also eat many insects and their larvae, including termites, aphids, beetles, weevils, caterpillars, moths, and water boatmen.