Monitoring the molecular mechanisms of insecticide resistance in Spodoptera frugiperda populations from Thailand

Marlen Saladini di Rovetino ¹, Bettina Lueke ², Kamonporn Masawang ³

⁰Université Côte d'Azur, INRAE, CNRS, ISA, Sophia Antipolis, France.

Pesticide Biochemistry and Physiology +

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September 7, 2025

View abstract on PubMed

Summary

Insecticide resistance in fall armyworm (Spodoptera frugiperda) in Thailand is driven by target-site mutations in sodium channels and acetylcholinesterase, alongside overexpressed P450 enzymes. This necessitates integrated pest management strategies.

Area Of Science

Entomology
Molecular Biology
Agricultural Science

Background

Spodoptera frugiperda is a significant invasive pest in Thailand, causing substantial crop damage, especially to maize.
Observed insecticide efficacy loss indicates emerging resistance in S. frugiperda populations.

Purpose Of The Study

To investigate the molecular mechanisms underlying insecticide resistance in Thai S. frugiperda populations.
To identify specific genetic mutations and gene expression patterns conferring resistance.

Main Methods

Analysis of mutations in insecticide target genes (voltage-dependent sodium channel, acetylcholinesterase).
Functional validation of mutations using recombinant enzyme inhibition studies.
Monitoring of cytochrome P450 gene expression and transcription factor levels.

Main Results

Identified three mutations in the voltage-dependent sodium channel (M944L, F1005C, I1011M) conferring pyrethroid resistance.
Detected F290V mutation in acetylcholinesterase (AChE), conferring resistance to organophosphates and carbamates, functionally validated.
Observed overexpression of CYP9A subfamily P450s and transcription factors (CncC, Maf), indicating metabolic resistance.

Conclusions

Resistance in Thai S. frugiperda involves both target-site modification and enhanced metabolic detoxification.
Effective and sustainable pest control requires strategies that address these dual resistance mechanisms.
Development of monitoring strategies for both resistance mechanisms is crucial for managing this pest.

Keywords:

Acetylcholinesterase CYP9A Fall armyworm Resistance Voltage-gated sodium channel