1553 EurAsian Journal of BioSciences Eurasia J Biosci 14, 1553-1560 (2020) Efficacy certain insecticides against spodoptera littoralis (boisd.) and bemisia tabaci (genn). infesting soybean plants and their associated predators A.A.A. Saleh 1* , Mohamed A. Hendawy 2 , A.S. Jabbar 3 , A.S.N. El-Hadary 1 1 Pl. Prot. Res. Inst., A RC, Giza, EGYPT 2 Pl. Prot. Dept., Fac. Agric. Zagazig Univ., EGYPT 3 Pl. Prot. Dept., Fac. Agric. AL - Muthanna Univ., IRAQ *Corresponding author: A.A.A. Saleh Abstract Field and laboratory experiments were carried out at plant protection research institute and the fields of Zagazig district on soybean during 2018 and 2019 seasons. The tested insecticides were Actelic, KZoil, Super-misrona and Actra against Spodoptera littoralis and Bemisia tabaci and associated predators. Results showed that Actelic was the most effective compound followed by Kz oil while Actra was the least effective one against Spodoptera littoralis, residual effects were 58.0, 43.0, 33.0 and 25.0%. The residual effect of B.tabaci nymphs were 75.42, 70.94, 86.63 and 20.63 for the same tested pesticides, Super-misrona, Actelic, KZoil, and Actra, respectively. . The results obviously revealed that primiphosmethyl(Actelic) and thiamethoxam (Actra) were the most effective compound causing in general, the highest percentage of C. undecimpunctata and C. carnea population reduction ether after three days post- treatment or after any of the two tested post-treatment periods. Keywords: spodoptera littoralis, bemisia tabaci, boisd, genn Saleh AAA, Hendawy MA, Jabbar AS, El-Hadary ASN (2020) Efficacy certain insecticides against spodoptera littoralis (boisd.) and bemisia tabaci (genn). infesting soybean plants and their associated predators. Eurasia J Biosci 14: 1553-1560. © 2020 Saleh et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License. INTRODUCTION Soybean Glycine max is one of the main crops all over the world. It is an important crop providing the abundant proteins and vegetable oils for human nutrition (Harman et al., 2004). To protect crops in modern agriculture and an increasingly regulated world, natural plant-based insecticides can be a feasible plant pest management method and an attractive alternative to synthetic chemical insecticides because botanicals reputedly pose little threat to the environment, non- target organisms or to human health (Isman, 2006). A number of plant substances have been considered for use as insecticides, antifeedants or repellents, which include terpenes, flavonoids, alkaloids, phenols, and other related compounds (Adeyemi, 2010). Effective control of insect pests’ infestation can be achieved through use of the conventional insecticides. However, conventional pesticides are expensive, result in ecological pollution, health hazards and cause pest resurgence by destroying the natural enemies (Isman, 2008). The effectiveness of imidacloprid and thiamethoxam as foliar application against the whitefly (Bemisia tabaci). These two insecticides did not affect spider population but the coccinellid population was reduced with increase of doses of imidacloprid. Imidacloprid @ 175 and 150 ml/ha were found more toxic than thiamethoxam @ 200 g/ha and imidacloprid @ 125 ml/ha Kar (2017). Thiamethoxam has been utilized as a key insecticide for control of B type B. tabaci for quite a long while in China with no known instances of resistance in field populations (Horowitz et al, 2009). Biological control is a satisfactory program in integrated pest management. Control of insect pests by bio control agents is defined as the action of these agents that maintains a pest population at a lower level (Sinha and Singh, 1979; Walker et al., 1984).Field crops attacked by a variety of insects and related pests, including aphids, cucumber beetles, seed corn maggot, squash bug, squash vine borer and two spotted spider mite. Scouting a field to estimate the number of pests present is an important component of effective management (Dinham, 2003). Direct and indirect effects of aphids feeding occur defoliation lead burning and even plant death are examples of direct effects. Indirect effects include decreases in photosynthesis and transpiration. This combination of effects on the host plant often reduces the amount of yield for that crop Received: July 2019 Accepted: May 2020 Printed: June 2020