Fen Edebiyat Fakültesi / Faculty of Letters and Science

Permanent URI for this collectionhttps://hdl.handle.net/11727/1396

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    Biochemical And Molecular Analyses Of Insecticide Resistance In Greenhouse Populations Of Bemisia Tabaci (Hemiptera: Aleyrodidae) In Türkiye
    (Başkent Üniversitesi Fen Edebiyat Fakültesi, 2024-04-04) Erdogan, Cem; Toprak, Umut; Gurkan, M. Oktay
    The sweet potato/cotton whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is one of the most destructive vegetable pests in greenhouses in Turkiye. While the preferred method of control primarily relies on insecticides such as neonicotinoids, organophosphates and pyrethroids, their intensive use has caused whiteflies to rapidly become resistant. Samples were collected from 13 Turkish B. tabaci greenhouse populations. Bioassays from the Marmara Region identified as high as a 53-fold increase in resistance to chlorpyrifos-ethyl, a 303-fold increase to imidacloprid and a 282-fold increase to acetamiprid. Bioassays in the Central Anatolia Region reported a 76-fold increase in resistance to deltamethrin and-15-fold increase to thiamethoxam. Most of the populations showed cross-resistance for neonicotinoids. All collected B. tabaci populations were determined to be MEAM 1 (also referred to as biotype B) for diagnostic band E0.14. The E0.14 esterase variant that helps to diagnose biotype B insects was found in all individuals from field populations. Almost all populations showed higher non-specific esterase, glutathione-S-transferase (GST) and monooxygenase activity when compared to susceptible SUD-S population. AChE insensitivity assays for individual B. tabaci suggest a target-site modification as a mechanism of resistance to chlorpyrifos-ethyl. This is the first report of AChE variants identified based on their sensitivities to chlorpyrifos ethyl-oxon and pirimicarb in Turkish B. tabaci populations. Fixed ace mutations in the target-site of organophosphates and pyrethroids were identified in six populations. Resistance to organophosphates and neonicotinoids were at least partially related to both ace mutations and insensitive AChE and monooxygenase activities, respectively. The results will help develop effective resistance management programs of B. tabaci in Turkiye.
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    Resistance to Common Insecticides and Mechanisms of Resistance in Aphis Pomi De Geer (Hemiptera: Aphididae), in Apple Orchards in Turkey
    (2023) Erdogan, Cem; Ozdem, Ayse; Alpkent, Yasin Nazim; Demiroz, Duygu; https://orcid.org/0000-0001-9537-3536; https://orcid.org/0000-0003-1501-1223; AAE-4306-2020; IZP-9920-2023
    The Green apple aphid, Aphis pomi de Geer (Hemiptera: Aphididae), is one of the most common and serious insect pests of apple orchards in Turkey. This species feeds on succulent tissue of trees, which can lead to leaf curling, stunting, distorted tip growth, black-sooty mold, and a vector of some plant viruses. Growers prefer to apply insecticide applications heavily to control the green apple aphid in commercial apple orchards. However, there have not been conducted any research study on insecticide resistance of A. pomi in Turkey. The resistance status of A. pomi populations collected from commercially apple orchards in the Central Anatolia region was investigated to: acetamiprid (neonicotinoid), the specific aphicide pirimicarb (carbamate), beta-cyfluthrin (synthetic pyrethroid), and chlorpyrifos-ethyl (organophosphate) insecticides. All populations were characterised for the first time using polyacrylamide gel electrophoresis to determine the esterase banding patterns. Biochemical assays revealed higher activity of total esterase. This is the first study conducted to determine glutathione S-transferase activity related to the insecticide resistance of A. pomi. It was determined that the resistance levels reached to 14.93 fold to acetamiprid, 3.74 fold to beta-cyfluthrin, 4.19 fold to chlorpyrifos-ethyl, and 4.33 fold to pirimicarb. The present study revealed neonicotinoid, organophosphate, carbamate, and pyrethroid resistance in A. pomi populations from the Central Anatolia Regions of Turkey. It also clearly showed that the enhanced esterase enzyme activity is the main resistance mechanism against carbamate pirimicarb resistance. The present study is the first insecticide resistance study on A. pomi for Turkey.