Insecticide resistance status and vector potential of Bemisia tabaci populations on vegetable crops in Türkiye

The sweet potato whitefly Bemisia tabaci (Gennadius, 1889) (Hemiptera: Aleyrodidae), is an economically important polyphagous pest species with a global distribution. This pest not only causes direct damage by sucking plant phloem sap but also transmits viruses and excretes honeydew, which can lead to the formation of black sooty mould, thereby intensifying its significance in agricultural regions. Although chemical insecticides have been extensively used for whitefly control, the development of resistance leading to control failures has been frequently documented. Here, we have initially assessed the efficacy of four commonly used insecticides (acetamiprid, sulfoxaflor, spirotetramat, cyantraniliprole) against whitefly populations through greenhouse trials across eight distinct locations. Additionally, we conducted a comprehensive molecular screening of 35 field populations to identify resistance mutations at the insecticide target sites and to detect plant pathogenic viruses. The results revealed that sulfoxaflor and cyantraniliprole exhibited the highest efficacy against nymphal stages of whiteflies, whereas acetamiprid was determined to be the most effective insecticide against adult stages. Several well-known target-site mutations in acetylcholinesterase (F331W), voltage-gated sodium channel (VGSC; M918L, L925I, T929V), and acetyl-CoA carboxylase (A2083V) were found to be widespread in Turkish B. tabaci populations. Additionally, two mutations, I936V and I936F, previously associated with pyrethroid resistance, were identified for the first time in the VGSC of B. tabaci. Conversely, no amino acid substitutions were detected in the amplified fragments of the ryanodine and nicotinic acetylcholine receptors. Furthermore, tomato chlorosis virus (ToCV) was detected in five field populations from Antalya. The widespread distribution of whitefly populations with multiple resistance mutations underscores the necessity of implementing integrated pest management programs in Turkish vegetable production areas.