Molecular evaluation of organophosphate and carbamate resistance in Bemisia tabaci (Gennadius, 1889) (Hemiptera: Aleyrodidae) populations from Türkiye

Chemical control has long been an effective strategy against Bemisia tabaci (Gennadius, 1889) (Hemiptera: Aleyrodidae); however, insecticide resistance increasingly complicates field management. Although the use of many organophosphate (OP) insecticides has been restricted in Türkiye, some active ingredients, such as pirimiphos-methyl, are still permitted. Moreover, no updated data on resistance in field populations have been reported in the past decade. In this study, the frequency of the F331W mutation, associated with OP and carbamate resistance, was investigated in B. tabaci populations sampled in 2023 from the Aegean and Mediterranean regions of Türkiye using the PCR-RFLP method and a large sample size. Of 360 individuals, 194 had the RR genotype and 166 had the RS genotype, while no SS genotype was detected. The overall frequency of the resistance-associated allele was 76.94%. Although this frequency was slightly higher in the Mediterranean region (78.61%) than in the Aegean region (75.28%), the difference was not statistically significant. The findings indicate that this allele is widespread in major agricultural production areas and appears to be fixed in some populations, particularly in Antalya and Muğla. These results emphasize the need for integrated pest management strategies, including the rotation of insecticides with different modes of action.