ORIGINAL RESEARCH ARTICLE Resistance development in Cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) to insecticides from Organophosphate, Thiadiazines and Thiourea derivatives V. S. Nagrare 1 & Babasaheb B. Fand 1 & V. Chinna Babu Naik 1 & Bhausaheb Naikwadi 1 & Vrushali Deshmukh 1 & Dharmendra Sinh 1 Received: 24 May 2019 /Accepted: 29 October 2019 # African Association of Insect Scientists 2019 Abstract Cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) is a highly invasive pest of cotton and other economically important agri-horticultural crops, worldwide. Majority of the cotton growers rely on chemical insecticides to control this pest. Indiscriminate use of insecticides has lead to development of resistance against some insecticides in recent years. Aiming to investigate the resistance development in P. solenopsis to some of the commonly used insecticides, Phenacoccus solenopsis colonies were collected from infested plants of cotton from four different locations namely Yavatmal, Wardha, Amravati and Akola districts of Vidarbha region of Maharashtra, India. The mealybugs were cultured on potato spouts in the laboratory for one generation to eliminate intermittent field infection of natural enemies and bio-assayed by leaf dip method in the laboratory. Results of bioassay indicated very high (RF 378.29) level of resistance against Thiadiazines (buprofezin) in mealybug population collected from Amravati, whereas resistance was found negligible at other locations. Low to very low level of resistance was recorded against organophosphates (monocrotophos, chlorpyrifos, quinalphos and acephate) and Thiourea deriv- atives (diafenthiuron) from all the locations. The results of the present study provide valuable information regarding selection of appropriate insecticides as one of the components of integrated management of P. solenopsis. Keywords Cotton mealybug . Phenacoccus solenopsis . Insecticides . Resistance Introduction Mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) infesting cotton (Gossypium hirsutum L.) was first reported in USA (Fuchs et al. 1991). Since then, the species exhibited its presence in major habitats including cultivated land, managed forests, horticultural orchards, urban and peri-urban areas and arid regions of the globe. Presence of Phenacoccus solenopsis has been reported from 46 countries (CABI 2018), among them, the major cotton producing coun- tries are USA (Fuchs et al. 1991), Pakistan (Abbas et al. 2005, Hodgson et al. 2008.), India (Hodgson et al. 2008; Nagrare et al. 2009), China (Wang et al. 2009; Wu and Zhang 2009), Australia (Admin 2010; Robinson and Tapim 2010), Brazil (da Silva 2012 ) and Egypt (El-Zahi et al. 2016 ). Phenacoccus solenopsis is highly invasive; its unforeseen out- break on cotton and other crops in many countries poses seri- ous threat to agricultural economy all over the world (Wang et al. 2010). It is widely spread all over the major cotton growing states of India. Cotton plants gets defoliated, stunted plant growth, obstruct photosynthesis, creates abnormality in plant and ultimately drying of plant or plant death due to its continuous feeding of the plant sap resulting in yield losses up to 50% (Nagrare et al. 2009). The pest is polyphagous and has wide host plants range over 267 from 64 families in India (Vennila et al. 2011, 2013; Nagrare et al. 2012; Vijay and Suresh 2013; Mandal et al. 2014; Maruthadurai and Singh 2015; Singh et al. 2016). Cotton is mostly grown in monoculture and is a highly pesticide-intensive crop as the pesticide applications exercises right from sowing to harvesting. In India, share of cotton is 8.47% of total cropping area however, accounts for nearly 25.49% of the total pesticide consumption in the country * V. S. Nagrare vs.nagrare@gmail.com 1 ICAR-Central Institute for Cotton Research (CICR), P. B. No. 2, Shankar Nagar P. O, Nagpur 440010, India International Journal of Tropical Insect Science https://doi.org/10.1007/s42690-019-00068-9