SUMMARY A seed dressing of chlorfenvinphos, ethion or carbophenothion gave good control of wheat bulb fly (Leptohylemyia coarctata (Eall.)) particularly with late drilling, but was less effective with early sowings of winter wheat. The extra insurance of seed dressing against wheat bulb fly for early sowings was worth while where autumn egg numbers were high. “Dursban” (O, O‐diethy10–3, 5, 6‐trichloro‐2‐pyridyl phosphorothioate), formulated as a seed dressing, gave a good kill of larvae but was phytotoxic, particularly on a peaty loam soil.