Aphids are the major pests of plant crops in temperate areas of the world. They are monophagous as well as polyphagous and damage wheat, oilseeds, vegetables and fruit crops. This study was carried out to observe the effect of plant extracts and semiochemicals on physiology and performance of endoparasitoid of aphids, Diaeretiella rapae. Seven different treatments of semiochemicals and plant extract were applied on aphid pests, Sitobion avenae and Rhopalosiphum padi and parasitoid was released. The data regarding emergence, parasitism, sex ratio, tibia length, adult weight and adult longevity of parasitoid D. rapae after the application of treatments was studied and analyzed statistically. The study revealed that plant extract can be toxic to paprasitoid D. rapae. This study will help us to use those insecticide formulations, which not only kill the aphid pests but are also eco-friendly to natural enemies and our environment.