Abstract The South American tomato pinworm, Phthorimaea absoluta , is a major global tomato pest, and its control relies on insecticides. However, P. absoluta has developed resistance to most insecticides, leading to control failure under field conditions. Chlorantraniliprole, a diamide insecticide, has been widely employed in spraying programs. Nevertheless, the current status of chlorantraniliprole resistance in P. absoluta has not been well examined in Türkiye. This study investigated chlorantraniliprole resistance and the associated mechanisms in field populations of P. absoluta . Toxicity assays revealed that P. absoluta developed moderate to high levels of resistance (13.8- to 97.7-fold) to chlorantraniliprole. Biochemical assays showed a significant correlation between cytochrome P450 monooxygenase activity and resistance ( R 2 = 0.677, P < 0.05). Although no significant association was found between ryanodine receptor (RyR) expression levels and resistance ( R 2 = 0.145, P < 0.05), several known target-site mutations (I4746M/K and G4903E/V) were identified. Lastly, the P. absoluta RyR (PaRyR) gene sequence was characterised, revealing a 15,633-bp open reading frame encoding 5,121 amino acid residues, with 78% sequence identity to RyR isoforms from other insects. PaRyR was predicted to embrace all the hallmarks of RyR, including a well-conserved C-terminal domain, six transmembrane domains, and a large N-terminal domain. These findings provide insights into chlorantraniliprole resistance mechanisms and will inform future resistance management strategies in P. absoluta .
Atış et al. (Wed,) studied this question.