Dominant fitness costs of abamectin resistance in Plutella xylostella

Authors

  • Ran Wang,

    1. Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing, China
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  • Yidong Wu

    Corresponding author
    1. Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Nanjing, China
    • Correspondence to: Yidong Wu, College of Plant Protection, Nanjing Agricultural Univeristy, Nanjing 210095, China. E-mail: wyd@njau.edu.cn

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Abstract

BACKGROUND

The TH-Abm strain of Plutella xylostella, exhibiting 23 670-fold resistance to abamectin, was selected from a field-evolved multiresistant population. By repeated backcrossing to a susceptible strain (Roth) and selection with abamectin, the resistance trait of TH-Abm was introgressed into Roth to generate a near-isogenic strain (Roth-Abm). Fitness costs associated with abamectin resistance were examined in Roth-Abm.

RESULTS

Compared with Roth, Roth-Abm obtained 11 500-fold resistance to abamectin and 364 000-, 12- and 12-fold cross-resistance to emamectin benzoate, spinosad and fipronil respectively. Roth-Abm has a significantly longer pupal development time, lesser female pupal weight and lower larval survival than Roth. Female fecundity and egg viability are significantly lower in Roth-Abm than in Roth. All of the above fitness components of the F1 progeny from Roth × Roth-Abm are similar to those of Roth-Abm and are significantly lower than those of Roth. By comparing with the net replacement rate (R0) of Roth, the fitness of Roth-Abm, F1a (Roth male × Roth-Abm) and F1b (Roth female × Roth-Abm) are 0.50, 0.50 and 0.53 respectively.

CONCLUSION

Abamectin resistance in Roth-Abm results in significant fitness costs, and the fitness costs are autosomal and dominant. Rotation of abamectin with other insecticides without cross-resistance could be especially useful for delaying abamectin resistance in P. xylostella. © 2014 Society of Chemical Industry

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