Indian Journal of Entomology, 78(1): 15-23 (2016) EFFICACY OF DIAFENTHIURON 47.8 SC AGAINST SUCKING PESTS OF COTTON AND ITS SAFETY TO NATURAL ENEMIES D. R. BAJYA,* M. RANJITH, M. C. LAKHARAN AND S. K. RAZA Division of Bioscience, Institute of Pesticide Formulation Technology, Sector-20, Udyog Vihar, Gurgaon, Haryana – 122 016 *Email: deva.bajya@gmail.com ABSTRACT Field studies were undertaken at research farm, IPFT, Gurgaon to study the comparative bioefficacy of diafenthiuron 47.8 SC, at four doses viz ., 191.2 g a.i./ha, 215.1 g a.i./ha, 239.0 g a.i./ha and 286.8 g a.i./ha along with market sample diafenthiuruon 50 WP @ 300 g a.i./ha and imidacloprid 17.8 SL @ 20.0 ml/ha against sucking pests of cotton and its safety to natural enemies during kharif, 2012-13 and 2013-14. Diafenthiuron 47.8 SC @ 286.8 g a.i./ha was highly effective in suppressing the sucking pests viz., Amrasca biguttula biguttula (Ishida), Aphis gossypii (Glover), Bemisia tabaci (Gennadius) and Scirtothrips dorsalis Hood, and it had no adverse effects on the natural enemies. Key words: Bioefficacy, diafenthiuron, sucking pests, cotton and natural enemies The pest spectrum of cotton is quite complex and as many as 200 species of insects have been reported at different stages of crop growth in India (Anon., 2011). Apart from boll worm complex, its productivity is abominably reduced due to heavy infestation of sucking pest complex viz ., Bemisia tabaci (Gennadius), Amrasca biguttula biguttula (Ishida), Aphis gossypii (Glover) and Scirtothrips dorsalis Hood. Introduction of transgenic cotton in India by 2002, promisingly reduced the boll worm complex but boosted the sucking pest complex resulting in 21.2% loss (Dhawan et al., 1988). Pesticide application is an important strategy followed by farmers to prevent sucking pest complex. However, over time targeted pests have developed resistance to pesticides necessitating increased applications. The right choice of chemical pesticides is not governed by its toxicity alone, but depends on their safety to natural enemies in the ecosystem and the environment (Stanley, 2007). Registered insecticides require repeated application in higher doses and it might result in adverse effects on the environment and health. In order to circumvent the problems, replacement of conventional insecticides with new powerful molecules at lower dose is necessary (Shivanna et al., 2012). New formulations and new sources of existing molecules are likely to hold superiority in terms of higher toxicity, pest suppression, safety to natural enemies and non-target organisms, reduced spray dosages and rounds of spray and the benefits accrued in terms of savings in labour and time. Diafenthiuron, a thiourea compound, which inhibits mitochondrial energy metabolism (ATP synthesis) (Ruder and Kayser, 1992) and moulting was viewed as a viable tool for managing insects and mites. It has been reported to be effective against sucking pests like Bemisia tabaci and Amrasca biguttula (Ishida) in brinjal (Patel et al., 2006), all sucking pests in cotton (Chinnabbai et al., 2000; Kranthi et al., 2004). Also, it was reported to be safe to parasitoids viz., Cotesia plutellae Kurdjumov (Zuhua and Shushang, 1998) and predators viz ., Chrysoperla carnea (Stephens) (Preetha et al., 2009) and Menochilus sexmaculatus (Fabricius) (Stanley, 2007). In the present study diafenthiuron was assessed along with recommended insecticides against sucking pests of cotton. The main objective of the study was not only to compare efficacy of diafenthiuron 47.8SC against the sucking pests of cotton but also evaluate its safety to natural enemies. MATERIALS AND METHODS The study was carried out in the research farm at Institute of Pesticide Formulation Technology, Gurgaon, Haryana during kharif, 2012-13 and 2013- 14. It was laid in randomized block design with seven treatments replicated thrice including the untreated check. Cotton variety RCH -317 was sown during third week of May, 2012 and during first week of June, 2013 in plots of 6×5 m 2 with a spacing of 90 cm×60 cm. The crop was raised adopting standard agronomic DOI No. 10.5958/0974-8172.2016.00003.1