# Evolving resistance patterns in Tetranychus urticae and Bemisia tabaci in Greece

## TL;DR

This study tracks pesticide resistance in two major pests in Greece, showing they have developed resistance to multiple chemicals, stressing the need for better pest management.

## Contribution

The study provides new resistance surveillance data for Tetranychus urticae and Bemisia tabaci in Greece using bioassays and molecular markers.

## Key findings

- Tetranychus urticae populations show reduced sensitivity to abamectin, hexythiazox, and fenpyroximate.
- Multiple resistance mutations were detected at high frequencies in T. urticae and B. tabaci populations.
- Integrated pest management strategies are urgently needed to address evolving resistance.

## Abstract

Pesticide resistance in agricultural pests remains a major barrier to effective and sustainable crop protection. In this study, we assessed the current resistance status of two key pests, Tetranychus urticae and Bemisia tabaci, in major agricultural regions of Greece. A total of 25 field populations (19 of T. urticae and six of B. tabaci) were collected between 2023 and 2025 and tested using single‐dose bioassays and droplet digital PCR (ddPCR) for target‐site resistance mutations.

The results revealed significant variability in susceptibility to multiple acaricides and insecticides. Several T. urticae populations displaying reduced sensitivity to abamectin, hexythiazox, and fenpyroximate. Resistance mutations such as I321T (GluCl3), I1017F (CHS1), F1538I (vgsc), and G126S (cytb) were detected simultaneously at high frequencies in several T. urticae populations, indicating multi‐resistant phenotypes. A widespread occurrence of F331W (ace1), L925I/T929V (vgsc), and A2083V (acc) mutations were recorded in B. tabaci, showing the dynamics of resistance to organophosphates, pyrethroids, and ketoenols, respectively.

Our findings underscore the ongoing evolution of resistance in these pests and highlight the need for integrated management strategies that include regular resistance monitoring and judicious pesticide use. This study provides resistance surveillance data to guide pest control decisions and promote sustainable Integrated Pest Management (IPM) in Greece. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Greek populations of T. urticae and B. tabaci exhibit evolving multi‐resistance, confirmed by bioassays and molecular markers, highlighting the urgent need for evidence‐based resistance monitoring in IPM.