Eggs (24–28 h old) of Delia radicum (L.) were treated with the same doses of diflubenzuron, methoprene, juvenile hormone I, or precocene II. Diflubenzuron significantly reduced egg hatching compared with untreated and solvent-treated controls. Methoprene had a delayed effect, preventing eclosion of adults from pupae that subsequently developed from treated eggs. A commercial formulation of diflubenzuron, Dimilin®, significantly suppressed and delayed hatching of eggs treated when 3–7 h old but not of eggs treated when 24–48 h old. Diflubenzuron may be as effective as the commercial insecticide carbofuran in protecting rutabaga slices from damage, as all larvae that did hatch died shortly afterwards.