50 Indian Journal of Agricultural Sciences 89 (11): 1802–7, November 2019/Article Effect of temperature and cropping sequence on the infestation pattern of Bemisia tabaci in potato MOHD ABAS SHAH 1 , KAMLESH MALIK 2 , ANUJ BHATNAGAR 3 , SUBHASH KATARE 4 , SANJEEV SHARMA 5 and SWARUP KUMAR CHAKRABARTI 6 ICAR-Central Potato Research Station, Jalandhar, Punjab 144 026 India Received: 23 April 2018; Accepted: 06 May 2019 ABSTRACT In India, more than 85% of the total potato production is realised from the subtropical Indo-Gangetic plains where potato is cultivated during winter. The cotton whitefy, B. tabaci is a major pest of potato as it transmits the Tomato leaf curl New Delhi virus (potato) causing the Apical leaf curl disease which leads to huge yield losses. The population dynamics of cotton whitefy was studied at 12 locations across the northern plains of India from 2015–17. It was observed that the cotton whitefy appears on potato immediately after crop emergence. The whitefy adults exhibited four different patterns of population dynamics at different locations. Whitefies remained on the potato crop as long as minimum daily temperature was above 10–12ºC after which the whitefies either disappeared from the crops or their fight activity was considerably reduced as indicted by the yellow sticky trap catch data. The whitefy incidence was higher at locations where potato is preceded by crops preferred by whitefy such as cotton, broad beans, groundnut etc. Perusal of the data on number of eggs laid and ensuing nymphs per plant indicated that the contribution of immigrating adults to the whitefy population is much higher than that of the colonising population for major part of the crop period. Thus, in addition to temperature, cropping sequence acts as a major factor in shaping the pattern of whitefy infestation. The results will help in deciding cropping pattern and better timing of insecticidal applications for healthy seed potato production. Key words: Bemisia tabaci, Migration, Population dynamics, Potato, Seasonal carryover, Threshold temperature Present address: 1 Scientist (mabas.shah@icar.gov.in), ICAR- Central Potato Research Station, Jalandhar, Punjab; 2,3 Principal Scientist (malikkamlesh7@gmail.com, dr.anujbhatnagar@gmail. com), ICAR-Central Potato Research Station, Modipuram, Uttar Pradesh; 4 Senior Scientist (dwr.katare@gmail.com), ICAR-Central Potato Research Station, Gwalior, Madhya Pradesh; 5 Principal Scientist and Head (sanjeevsharma.cpri@gmail.com), 6 Director (chakrabarti.sk@icar.gov.in), ICAR-Central Potato Research Institute, Shimla, Himachal Pradesh. India is the 2 nd largest producer of potato in the world (FAOSTAT 2017) with more than 85% of India’s potatoes grown in the vast Indo-Gangetic plains of north India (subtropics) during short winter days from October to March in contrast to typical potato growing areas with temperate climate (Khurana and Naik 2003). The cotton whitefy, Bemisia tabaci (Gennadius), being a pest of tropical and subtropical areas is a major component of the potato seed production complex in India (Chandel et al. 2010). Although it does not infict any discernible direct damage to potato, it transmits the Tomato leaf curl New Delhi virus (ToLCNDV) leading to Potato apical leaf curl disease (Jeevalatha et al. 2017) which is one of the most important diseases of potato in India now (Sridhar et al. 2016, Bhatnagar et al. 2017). The population dynamics of whitefy infesting potato crops in India has been attempted at various locations e.g. Bhatnagar (2007, 2009) from Gwalior, Lakra (2003, 2005) and Kumar and Gupta (2016) from Hisar, Kishore et al. (2005), and Malik and Singh (2007) from Modipuram, and Amitava et al. (2010) from Nadia (West Bengal). These studies evaluated the location specifc trends of the population dynamics of whitefy with correlation to local weather parameters. However, a comprehensive study with holistic view of the system is lacking. B. tabaci being a multivoltine insect has no diapause or quiescent stages, its populations are sustained through the continual exploitation of multiple host resources, both wild and cultivated, over the annual cycle. Therefore, in addition to temperature, cropping sequence also shapes the pattern of whitefy infestation in crops (Murugan and Uthamasamy 2001, Naranjo et al. 2009). Quality seed potato production needs to contain the virus infection levels below critical thresholds (Chandel et al. 2010); hence the effcient management of whitefy vector on potato is critically important. In the current study, the whitefy infestation pattern was evaluated with respect to ambient temperature and the nature of cropping sequence https://doi.org/10.56093/ijas.v89i11.95296