On citrus leaves, a laboratory trial was conducted to test the effect of several compounds against the nymphs of the cottony cushion scale, Icerya purchasi, under laboratory conditions at Plant Protection Dept., Faculty of Agriculture, South Valley University, Qena governorate, Egypt. Two insecticides (thiamethoxam 25% and malathion 57%), mineral oil (active cable 2), three plant oils (clove oil, mint oil and ginger oil) and two plant extracts (garlic and moringa) were used. The results demonstrated that under laboratory circumstances, the investigated substances on I. purchasi were varied. The tested compounds could be descendingly arranged as follows:  thiamethoxam 25%, malathion 57%, active cable 2, clove oil, mint oil, ginger oil, garlic and moringa. The corresponding LC₅₀ values after 72 h. were 0.02, 0.24, 0.91, 3.11, 3.44, 4.17, 31.36 and 35.06 ppm. While, LC₉₀ values were 0.10, 1.11, 4.56, 6.87, 7.92, 11.36, 121.96 and 178.86 ppm. Also, the insecticidal efficiency of thiamethoxam 25% and malathion 57% showed the highest toxicity against nymphs of scale insect on citrus leaves, while the plant extract, moringa showed the lowest effect.