Lyonetia clerkella Linn. (Lepidoptera: Lyonetiidae) is one of the most destructive insect pests in many parts of the Kashmir valley. In order to find an effective control agent against this lepidopteran pest, we determined the effectiveness of four synthetic insecticides, viz. Dichlorvas 76EC, Chlorpyriphos 20EC, Dimethoate 30EC, and Cartap hydrochloride 4% GR under both field as well as in laboratory conditions. The distilled water was also used as a control in the experiments. The mortality caused by these insecticides was recorded in both larval as well as in adult bioassay experiments. In the larval bioassay experiment, the highest mortality was caused by Cartap hydrochloride 4% GR (93.13%) followed by Dimethoate 30EC (88.97%), whereas in adult bioassay experiment, the highest mortality was caused by Dimethoate 30EC (94.03%). Results obtained in the present study are promising and may be used as a control strategy for the management of this severe leaf miner pest; however, no recommendations concerning the potential use of insecticides for apple orchards can be given, and further studies are needed in this respect, especially under field conditions.