Comparative effectiveness of the tested compounds against l' instar larvae of PTM infesting potato plants under greenhouse conditions showed that the tested compounds could be arranged descendingly according to their boxidty as follows : xentari, abamectin, profenofos, pirimiphos - methyl, Agerin, MVP II, Dipel 2x, Ecotech and Verotecto. The residual effect of tested compounds against Potato Tuber moth (PTM) infesting potato plants indicated that all tested bio - compounds gave 100% mortality as initial effect:. The tested insecticides could be arranged descendingly by relative toxicity, as follows:xentari, abamectin, profenofos, pirimiphos-methyl, Agerin, MVP II, Dipel 2x, Ecotech and Verotecto. While on tomato plants, the results indicated that all tested bio - compounds gave 100% mortality as Initial effect. The data indicated that xentari, profenofos and abamectin were the most toxic to 1¹ instar larvae of PTM, pirimiphos - methyl, MVP II and Agerin had a moderate toxic effect, while Dipel 2x, Ecotech and Verotecto were the least toxic to PTM larvae. Under field conditions, abamectin.gave the highest residual half - life (RL_so) value followed by profenofos and xentari The lowest results were obtained with Again, Dipel 2x, Ecotech and Verotecto, on potato plants. While on tomato plants, abamectin, profenofos, pirimiphos - methyl, xentari and Agerin gave full initial kill of 100%. The tested insecticides could be arranged descendingly according to their effect as follows : abamectin, profenofos, pirimiphos - methyl, xentari, Agerin, MVP II, Verotecto.