Effect of Semiochemicals and Plant Extracts on Performance of Aphid Parasitoid, Diaeretiella rapae S. Bushra 1, *, M. Tariq 1 , M. Naeem 1 , M. Ashfaq 1 , I. Bodlah 1 and M. Ali 2 1 Department of Entomology, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi 2 Institute of Agricultural Sciences, University of Punjab, Lahore Article Information Received 18 October 2015 Revised 09 November 2016 Accepted 20 November 2016 Available online 28 March 2017 Authors’ Contributions MT and MN conceived and designed the study. SB performed all the experiments and wrote the article. IB and MA analyzed the data. Key words Beauveria bassiana, Musca domestica, Biological aspects, Sublethal effects. 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. INTRODUCTION A bout 5000 aphid species are crop pests (Morrison and Peairs, 1998). They weaken the plant growth by sucking sap, transmit viruses in their host and result the yield losses (Dehkordi et al., 2013; Asiry, 2015). Aphid pests Sitobion avenae and Rhopalosiphum padi coexist in spring wheat crop and cause economic damage (Chen et al., 2007). Several insecticides are used to control these aphids which are also harmful. The adverse effects of insecticides on mammals are caused by insecticide residues left on edible crops when they are consumed (Bale et al., 2008). One the other hand, some plants consist of valuable active chemicals such as alkaloids, semiochemicals, terpenoids, glycosides, flavonoids and cucurbitacins, which are toxic to insect pests (Koul and Walia, 2009). These extracts are used to reduce the losses caused by agricultural pests by killing them. These include neem, turmeric, garlic etc. These plant extracts are used in IPM, medicine and industry. Some of the plant extracts have a negative impact on natural enemies like parasitiods (Sohail et al., 2012). The braconid wasp, Diaeretiella rapae is an endoparasitoid of aphids (Fathipour et al., 2006). But, parasitoid performance also increases with increase in aphid population (Holling, 1959). Aphid parasitoids need * Corresponding author: bushraentomologist@gmail.com 0030-9923/2017/0002-0615 $ 9.00/0 Copyright 2017 Zoological Society of Pakistan chemical volatiles to find suitable hosts and reproduce. These chemical volatiles are semiochemicals that indicate the presence of their hosts (Blande et al., 2007). Semiochemicals are volatile chemical compounds which are emitted by plants as alarming signals, when they are damaged. They repel herbivores (Francis et al., 2004; Verheggen et al., 2007). They attract parasitoid wasps which are antagonistic to aphid pests (El-Sayed et al., 2006). Among semiochemicals, aphid alarm pheromone has the direct influence on aphid density (Xiangyu et al., 2002). This pheromone consists α-pinene, β-pinene and E-β-farnesene (Eβf) and some trace compounds. These compounds attract natural enemies of aphids (Sasso et al., 2007; Leroy et al., 2012). In this study the effect of different semiochemicals and plant extracts was studied on the performance and physiology of aphid parasitoid, Diaeretiella rapae. This study will help us to use those insecticide formulations, which not only kill the aphid pests but they are also eco- friendly to natural enemies and environment. Long term studies on the effect of semiochemicals and plant extracts towards pests and natural enemies are required before recommending their use as pesticide (Asiry, 2015; Arshad et al., 2016). In this way, we can conserve natural enemies and manage the aphid pests. MATERIALS AND METHODS Wheat seeds of variety Fareed-06 were sown in ABSTRACT Pakistan J. Zool., vol. 49(2), pp 615-621, 2017. DOI: http://dx.doi.org/10.17582/journal.pjz/2017.49.2.615.621