Investigations on the resistance status to some insecticides of leptinotarsa decemlineata say. (coleoptera: chrysomelidae) in patato cultivation areas and the possibilities of using diatomaceous earth and zeolite in resistance management.

In this study, the resistance levels of the Colorado potato beetle (Leptinotarsa decemlineata Say.) to the insecticides acetamiprid, deltamethrin, and spinosad were determined in populations from the major potato-producing provinces of Afyonkarahisar, Niğde, and Konya in Türkiye. In addition, the biochemical resistance mechanisms were investigated by measuring carboxylesterase and glutathione S-transferase (GST) enzyme activities in resistant populations. The synergistic effects of diatomaceous earth and zeolite in combination with these insecticides were also evaluated. Larvae and adults of the pest were collected from two different locations in potato cultivation areas of Afyonkarahisar (Sandıklı, Şuhut), Niğde (Konaklı, Çiftlik) and Konya (Çumra, Selçuklu) provinces, starting from June 2023. In acetamiprid application, after 24 hours exposure period, the resistance rates (RR50) were determined as 74.30 in Sandıklı, 59.47 in Şuhut, 54.40 in Konaklı, 48.81 in Çiftlik, 25.26 in Çumra, and 31.46 fold in Selçuklu population. In deltamethrin application, the RR50 were determined as 19.04 in Sandıklı, 14.68 in Şuhut, 10.84 in Konaklı, 14.34 in Çiftlik, 7.41 in Çumra, and 8.10 fold in Selçuklu population. In spinosad application, RR50 were determined as 22.00 in Sandıklı, 20.35 in Şuhut, 14.82 in Konaklı, 13.54 in Çiftlik, 12.00 in Çumra and 7.94 fold in Selçuklu population. Bioassay results revealed high resistance levels in the Afyonkarahisar and Niğde populations and moderate resistance in the Konya populations. Synergism rates (SR50 values) obtained in Acetamiprid+ diatomaceous earth (2% w/v) application were determined as 3.21 in Sandıklı, 5.19 in Konaklı, 2.60 in Çumra and 3.72 in Selçuklu population. In deltamethrin + diatomaceous earth (%2 w/v) application SR50 was determined as 3.74 in Sandıklı, 4.28 in Konaklı, 2.47 in Çumra, 3.10 in Selçuklu population. In spinosad + diatomaceous earth (%2 w/v) application SR50 was determined as 2.91 in Sandıklı, 4.27 in Konaklı, 4.67 in Çumra, 2.39 in Selçuklu population. Zeolite showed an antagonistic effect rather than a synergistic effect when mixed with insecticides. In studies conducted on susceptible population, the synergism ratio (SR50 values) obtained from Acetamiprid + zeolite (2% w/v) application was determined as 0.52 in 48-hour exposure period, 0.41 in deltamethrin + zeolite (2% w/v) application, and 0.39 in spinosad + zeolite (2% w/v) application. Diatomaceous earth showed significant synergistic effects when combined with insecticides, whereas zeolite exhibited antagonistic interactions. According to the total carboxylesterase enzyme activity results determined as a result of kinetic reading in microplate cells in Leptinotarsa decemlineata populations, when compared to the susceptible population, an increase of 3.62 in Sandıklı, 2.35 in Selçuklu, 2.28 in Çumra, 2.15 in Çiftlik and 1.34-fold in Şuhut population was determined. Glutathione-s transferase (GST) enzyme activity rates were determined as 1.29 in Sandıklı, 2.59 in Şuhut, 1.46 in Çiftlik and 1.66-fold in Selçuklu population. These findings provide valuable insights for the development of resistance management strategies against L. decemlineata.