At the Entomological Laboratory in the Chair for Phytomedicine, Agricultural Engineering, Field Crops Production, Pasture and Grassland Management (Dept. of Agronomy, Biotechnical Faculty in Ljubljana) we performed laboratory experiment of insecticidal efficacy of spinosad and spinetoram against Sitophilus spp. weevils in the rearing chambers in 2016. In the experiment we used adults of Sitophilus granarius, S. oryzae and S. zeamais from Serbia, and adults of S. zeamais from Slovenia, which were grown in the grains of winter wheat under room conditions for the purposes of laboratory investigation. In the rearing chambers we tested the efficacy of insecticides spinosad and spinetoram to adults in three different concentrations (0,5, 1,0, and 2,0 mg active ingredient/kg grain) at 25 °C and 60 % relative humidity. The experiment was carried out in 100 ml vials, which were filled with grains of four winter wheat varieties, i.e. ‘Arezzo’, ‘Fidelius’, ‘Cimabue’, and ‘Olimpija’. All treatments were tested in 10 repetitions. Mortality of the weevils was assessed 7, 14, and 21 days after their exposal to both insecticides. Results of our experiment showed that spinetoram influenced higher mortality (90 %) of the beetles compared to spinosad (84 %). Between different winter wheat varieties we confirmed differences in mortality of the adults, since the highest mortality (96 %) was established in varieties 'Olimpija' and 'Cimabue', and the lowest in varieties 'Arezzo' and 'Fidelius', which were treated with fungicides. The highest mortality was confirmed with Serbial populations of S. granarius (94 %) and S. oryzae (95 %).
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