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<p>The widespread adoption of Bt cotton has significantly transformed pest management in cotton cultivation by effectively controlling key lepidopteran pests. However, the evolution of resistance in pink bollworm, <i>Pectinophora gossypiella</i> to Cry1Ac and Cry2Ab toxins threatens the sustainability of Bt technology. This study was conducted to assess the resistance status of <i>P. gossypiella</i> populations in major cotton-growing regions of South India, including Andhra Pradesh, Telangana, and Karnataka, and to evaluate their developmental biology under varied Cry toxin exposure levels. A diet-incorporation bioassay was performed to determine the median lethal concentration (LC₅₀) for Cry1Ac and Cry2Ab. Resistance ratios (RR) were calculated using a susceptible laboratory strain as a baseline. Results revealed significant variability in resistance among field populations, with the highest resistance observed in Guntur (RR = 724.2 for Cry1Ac, 1442.0 for Cry2Ab), followed by Prakasam. The correlation analysis revealed a strong negative relationship between toxin concentration and key developmental parameters, indicating that higher toxin levels significantly hinder the development of susceptible populations, highlighting the sublethal effects of Cry toxins. Resistant populations exhibited prolonged developmental periods but maintained higher survival rates, suggesting potential physiological adaptations. The findings underscore the urgent need for resistance management strategies, including the integration of non-Bt refuges, high-dose/refuge strategies, and alternative pest control measures. Continuous resistance monitoring through molecular and biochemical assays is crucial for designing effective resistance mitigation strategies. The study highlights the alarming spread of resistance in <i>P. gossypiella</i>, emphasizing the need for proactive interventions to sustain the efficacy of Bt cotton in India. Clinical trial number: not applicable.</p>

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Resistance of pink bollworm Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) to Cry1Ac and Cry2Ab toxins in major cotton-growing regions of South India

  • 期刊论文

  • 发表日期：

    2026年6月18日

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  • Naduvalakeri Maruti,
  • N. V.V. Durga Prasad,
  • V. Chinna Babu Naik,
  • C. Sandhya Rani,
  • Suresh R. Jambagi

摘要

The widespread adoption of Bt cotton has significantly transformed pest management in cotton cultivation by effectively controlling key lepidopteran pests. However, the evolution of resistance in pink bollworm, Pectinophora gossypiella to Cry1Ac and Cry2Ab toxins threatens the sustainability of Bt technology. This study was conducted to assess the resistance status of P. gossypiella populations in major cotton-growing regions of South India, including Andhra Pradesh, Telangana, and Karnataka, and to evaluate their developmental biology under varied Cry toxin exposure levels. A diet-incorporation bioassay was performed to determine the median lethal concentration (LC₅₀) for Cry1Ac and Cry2Ab. Resistance ratios (RR) were calculated using a susceptible laboratory strain as a baseline. Results revealed significant variability in resistance among field populations, with the highest resistance observed in Guntur (RR = 724.2 for Cry1Ac, 1442.0 for Cry2Ab), followed by Prakasam. The correlation analysis revealed a strong negative relationship between toxin concentration and key developmental parameters, indicating that higher toxin levels significantly hinder the development of susceptible populations, highlighting the sublethal effects of Cry toxins. Resistant populations exhibited prolonged developmental periods but maintained higher survival rates, suggesting potential physiological adaptations. The findings underscore the urgent need for resistance management strategies, including the integration of non-Bt refuges, high-dose/refuge strategies, and alternative pest control measures. Continuous resistance monitoring through molecular and biochemical assays is crucial for designing effective resistance mitigation strategies. The study highlights the alarming spread of resistance in P. gossypiella, emphasizing the need for proactive interventions to sustain the efficacy of Bt cotton in India. Clinical trial number: not applicable.