Status of insecticide resistance in Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae) from 1997 to 2019: cross-resistance, genetics, biological costs, underlying mechanisms, and implications for management

The diamondback moth, Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae), is a global pest of crucifer crops, mainly controlled with insecticides. However, this moth has shown populations from different geographical regions that are resistant to various synthetic insecticides, including organophosphates, pyrethroids, new molecules, and microbial-derived pesticides owing to repeated applications of these insecticides. This review is an effort to explore reported cases of insecticide resistance and mechanisms involved in P. xylostella throughout the world. It also includes a comprehensive overview of the mode of inheritance and fitness costs associated with the resistance of P. xylostella to different insecticides. Data from 20 research papers about field and laboratory resistance to various organochlorines and pyrethroids, and 54 papers on resistance to new chemical and microbial insecticides, showed the varying resistance levels in P. xylostella from different parts of the world. Cross-resistance results were also presented in 17 published papers. Moreover, the collected data of 25 research publications about resistance inheritance to various insecticides revealed that 84% of the published papers confirmed autosomal resistance, while sex-linked inheritance was confirmed in only 16% of the published literature. An association of high fitness costs with disadvantageous biological characteristics was evident from the summarized data of eight different studies. Studies about resistance mechanisms were presented in 32 published papers which depicted that metabolic resistance was prevalent over target sites. This effort will contribute to developing an effective management program to mitigate the resistance of P. xylostella to the main pest control strategies.