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Since 2002, transgenic crops that produce Cry1Ac and Cry2Ab toxins have been used in India to control bollworms. From 2002 to 2009, Bt-cotton effectively controlled the pink bollworm (PBW). However, since 2009 numerous studies have reported high survival of PBW on Bt-cotton expressing Cry1Ac and Cry2Ab toxins, indicating reduced susceptibility to Cry toxins expressed in Bt-cotton. In the current study, we attempted to estimate the frequency of resistance alleles to Cry1Ac and Cry2Ab toxins in a field collected population of pink bollworms from Andhra Pradesh. Resistance allele frequency was estimated using an F2 screen methodology for the first time after 17 years of Bt-cotton cultivation. Our study finds that the allele frequency for Cry1Ac is 0.082 and for Cry2Ab is 0.054, with a detection probability of greater than 97%. In our survey conducted in 2018–19 and 2019–20, we also noticed high survival and damage by PBW on Bt-cotton expressing Cry1Ac and Cry2Ab. Our survey report reveals, > 30% flower damage, > 90% green boll damage and > 80% locule damage by PBW on Bt-cotton expressing Cry1Ac and Cry2Ab toxins. [ABSTRACT FROM AUTHOR]

Pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) is an important pest of cotton worldwide; causing significant economic loss to cotton growers. Its control under field condition is difficult, as it remains inside the boll and feeds internally. Therefore, under this study we have evaluated different insecticides viz., Quinalphos 25% EC, Profenofos 50% EC, Thiodicarb 75% WP, Chlorantraniliprole 18.5% SC, Spinosad 45% SC, Neem oil (0.3% W/W), Cypermethrin 25% EC, Triazophos 40% EC, Deltamethrin 2.8% EC and the combination of Profenofos 40% + Cypermethrin 4% EC and Deltamethrin 1% + Triazophos 35% EC for the management of P. gossypiella in cotton under rainfed conditions. The results revealed that combination of Profenofos 40% + Cypermethrin 4% EC showed most effective and offered lowest number of exit holes (0.3 to 0.5), mines on epicarp (2.0 to 7.0), larvae/plant (0.3 to 1.0) and per cent locule damage (1.3 to 7.3%) in green bolls as compared to individual formulations. Among individual formulations, Cypermethrin 25% EC effectively controlled pink bollworm larval damage (0.3 to 1.1 exit holes, 3.3 to 4.0 mines on epicarp, 0.9 to 1.7 larvae and 1.3 to 13.0% locule damage in green bolls after 10 days of spray) as compared to other treatments. Further, maximum seed cotton yield was recorded (11.6 to 12.04 q/ha) in Profenofos 40% + Cypermethrin 4% EC treated fields. The integration of these insecticide molecules proved to be effective in the management of pink bollworm under field conditions. [ABSTRACT FROM AUTHOR]

The recent emergence of pink bollworm (PBW), Pectinophora gossypiella (Saunders) has posed serious ecological and economic implications for cotton production in India since 2017. The project "Insecticide Resistance Management (IRM): Dissemination of pink bollworm management strategies in Bt-cotton" was implemented consecutively for four years from 2018 -19, 2019–20, 2020-21 and 2021-22 in 21 districts across three cotton growing zones of the country. In each year, field demonstrations were conducted on 1050 acres of cotton area and mass awareness was created through outreach activities. With concerted and focused efforts, the PBW infestations could be brought down by 42.75% in 2018–19, 43.49% in 2019–20, 35.55% in 2020-21 and 33.77% in 2021-22 in the demonstration plots over the farmer practices. An increased benefit: cost ratios of 2.16:1, 2:1, 1.89:1 and 2.24:1 were realized during 2018–19, 2019–20, 2020-21 and 2021–22, respectively. Similarly, the average number of sprays for the control of cotton pests during the season was reduced to 5.02, 4.94, 5.19 and 5.18 in integrated pest management (IPM) fields as compared to 6.98, 7.66, 8.07 and 8.20 in non-integrated pest management (NIPM) fields in the corresponding years. Reduction in pesticide usage in IPM vs NIPM fields was 46.39% in terms of cost, and 38.96% in terms of volume during 2019-20 while concurrent percent reduction in pesticide usage was 41.03 & 39.33 during 2020-21 and 40.70 & 39.38 in 2021–22. Comparatively more seed cotton was harvested from IPM than NIPM fields i.e. 2190 vs 1820 kg/ha in 2018–19, 2049 vs 1715 kg/ha in 2019–20, 1881 vs 1585 kg/ha in 2020-21 and 1901 vs 1607 kg/ha in 2021–22. Significant success in reducing PBW infestation, pesticide usage and corresponding improvement in yield, economic benefits and environmental quality in terms of reduced EIQFUR has been achieved through IPM demonstrations. This area-wide success was achieved through collective efforts and active involvement of all concerned stakeholders. [Display omitted] • Pink bollworm has emerged as serious threat to Indian cotton production. • Areawide IPM strategies disseminated & mass awareness created through outreach. • Significant reduction in pest infestation and pesticide usage was achieved. • Realization of economic benefits to cotton growers was demonstrated. [ABSTRACT FROM AUTHOR]