Insecticide Resistance and Resistance Management Study of Synergism, Antagonism, and Resistance Mechanisms in Insecticide-Resistant Oxycarenus hyalinipennis (Hemiptera: Lygaeidae) Saif Ullah, 1 Masood Ejaz, and Sarfraz Ali Shad Department of Entomology, Faculty of Agricultural Sciences and Technology, Bahauddin Zakariya University, Multan, Punjab 60800, Pakistan (saif_entomologist@yahoo.com; masoodejaz1@gmail.com; sarfrazshad@bzu.edu.pk), and 1 Corresponding author, e-mail: saif_entomologist@yahoo.com Subject Editor: Aaron Gassmann Received 5 August 2016; Editorial decision 2 December 2016 Abstract Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae) is an economic and key pest of the Malvaceae family widely distributed in the world. Significant field resistance to cypermethrin (26.69-fold), chlorpyrifos (32.60- fold), methomyl (10.87), acetamiprid (20.63-fold), fipronil (5.84-fold), and spirotetramat (116.02-fold) has been reported. Cypermethrin combined with methomyl and spirotetramat, methomyl with spirotetramat, acetamiprid with spirotetramat, and fipronil with spirotetramat had synergistic effects (combination index, (CI) in a labora- tory population of O. hyalinipennis named Lab-PK. Methomyl combined with acetamiprid and acetamiprid with fipronil had synergistic effects on O. hyalinipennis in a field in Multan named Field-POP. Cypermethrin com- bined with methomyl and spirotetramat; chlorpyrifos with methomyl, acetamiprid, and spirotetramat; methomyl with acetamiprid and spirotetramat; and fipronil with spirotetramat also had synergistic effects on O. hyalinipennis in Field-POP. Enzyme inhibitors piperonyl butoxide and S,S,S-tri-n-butyl phosphorotrithioate significantly increased the toxicity of chlorpyrifos, methomyl, acetamiprid, and spirotetramat to O. hyalinipen- nis in Field-POP, suggesting a monooxygenase- and esterase-based resistance mechanism. However, fipronil did not synergize with PBO and DEF. This study suggests that insecticide mixtures showing synergism must be determined for insecticide resistance management and other strategies such as rotations, mosaics, and cultural control should also be considered for the management of O. hyalinipennis. Key words: Oxycarenus hyalinipennis, Lygaeidae, mixture, synergism, Pakistan Oxycarenus hyalinipennis Costa, is native to Africa and a key pest of cotton in many areas of the world (Dennis 1983, Henry 1983, Jaleel et al. 2014, Sanghi et al. 2014, Abbas et al. 2015a). It is a polypha- gous insect that feeds on at least 40 host plant species belonging to the Malvales order (Sanghi et al. 2014, El-Rahim et al. 2015). Both nymphs and adults feed on mature seed, soft young stems, and leaves, resulting in reduced yield, oil content, seed weight (Ananthakrishnan and Raman 1982, Sewify and Semeada 1993), and seed viability (Kirkpatrick 1923, Pearson 1958, Akram et al. 2013). During the ginning process, cotton lint can become stained with a pink color because of the crushing of O. hyalinipennis (Henry 1983, Khan and Ahmed 2000). All of these factors ultimately lead to a reduction in cotton yield and value (Smith and Brambila 2008). Successful management of insect pests is usually achieved with chemical control. However, continuous and frequent use of insecti- cides leads to the development of resistance in the insect pests (Ahmad 2008, 2009a). For example, the overuse of insecticides in Asia has led to resistance in O. hyalinipennis and it has become a major pest (Khan et al. 2014). Recently, resistance to multiple classes of insecticides has been reported in O. hyalinipennis in Pakistan (Ullah et al. 2016a). There is a need for insecticide mixtures that can be used for the successful control of the insect pests (Bhatti et al. 2013). A mixture with different modes of action can increase the effectiveness of resistance management programs because mix- tures potentially decrease resistance in field populations and provide more successful control than either rotation or sequential use of in- secticides (Attique et al. 2006, Ahmad et al. 2009). In this context, there is a report on the use of a mixture of organophosphate with pyrethroid that could effectively manage the target pest despite pyr- ethroid resistance (Martin et al. 2003b). In a resistant strain of Helicoverpa armigera (Hu ¨ bner), the use of organophosphate insecti- cides with pyrethroids significantly increased the toxicity by sup- pressing the resistance effect, either by additive or synergistic effects (Martin et al. 2003a). In contrast, organophosphates (chlorpyrifos) showed antagonistic effect with pyrethroid (cypermethrin) in Bemisia tabaci Gennadius (Ahmad 2007). Synergism is the V C The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com 615 Journal of Economic Entomology, 110(2), 2017, 615–623 doi: 10.1093/jee/tow302 Advance Access Publication Date: 1 February 2017 Research article Downloaded from https://academic.oup.com/jee/article/110/2/615/2965815 by guest on 07 June 2022