Three benzoylphenylurea insecticides, diflubenzuron, triflumuron, and teflubenzuron, were toxic when applied to eggs of Phyllonorycter blancardella (Fabr.) 0–2 and 4–6 days post-oviposition. Most treated eggs hatched but larvae died in the early instars. High larval mortalities also occurred when treatments were applied to foliage prior to oviposition. Treatments applied to larvae, especially older larvae, were less toxic than those applied to eggs. In the field, control was similar whether insecticides were applied during egg deposition, first hatch of eggs, or against early-instar larvae. Applications during egg deposition are suggested as optimal for control. Control of spotted tentiform leafminer with insect growth regulators was equivalent to that obtained with deltamethrin or methomyl.
Residues of diflubenzuron and triflumuron, applied pre-bloom, persisted until leaf drop 19 weeks later. Residues of teflubenzuron persisted for 9 weeks. Populations of spotted tentiform leafminer were suppressed throughout the season and residues of all insect growth regulators except teflubenzuron applied in May were toxic to larvae into October.