Abstract: 【Aim】This study aims to master the occurrence patterns of aphids in the wheat growing areas of northwestern Shandong, North China, explore their resistance levels to commonly used insecticides, and evaluate the field control efficacy of these insecticides against wheat aphids, so as to provide theoretical support for rational insecticide application and resistance management in wheat aphid control. 【Methods】The resistance levels of the wingless adults of Sitobion avenae and Rhopalosiphum padi to six commonly used chemical insecticides of four categories［lambda-cyhalothrin (pyrethroid), imidacloprid, thiamethoxam and acetamiprid (neonicotinoids), pymetrozine (pyridine), and emamectin benzoate (semi-synthetic antibiotic)］ were determined using the residual film method in glass tube. Concurrently, the population dynamics of wheat aphids in the field in northwestern Shandong were monitored from 2022 to 2024. The field control efficacy of the above six chemical insecticides and five biopesticides (Bacillus thuringiensis, rotenone, matrine, azadirachtin and veratrine) against wheat aphids was evaluated in May 2023. 【Results】 Bioassay results indicated that S. avenae exhibited moderate levels of resistance to acetamiprid and imidacloprid, and the median lethal concentraltion (LC₅₀) values of acetamiprid and imidacloprid against the wingless adults of S. avenae in 3 h were 2.800 and 3.871 μg/cm², respectively. R. padi showed decreased sensitivity to acetamiprid and pymetrozine, moderate level of resistance to lambda-cyhalothrin，and high level of resistance to imidacloprid, and the LC₅₀values of acetamiprid, pymetrozine, lambda-cyhalothrin and imidacloprid against the wingless adults of S. avenae in 3 h were 0.022, 0.593, 3.065 and 2.782 μg/cm², respectively. Both aphid species remained sensitive to the other tested insecticides. Field surveys revealed a parabolic trend in aphid occurrence in the wheat growing area of northwestern Shandong, with peak populations typically observed in mid-to-late May followed by decline in aphid number. Field efficacy trials demonstrated that biopesticides generally exhibited lower control efficacy against wheat aphids than chemical insecticides. Thiamethoxam, lambda-cyhalothrin, acetamiprid, B. thuringiensis and rotenone exhibited rapid action, achieving >75% control efficacy against wheat aphids at 3 d after application, significantly higher than the other six agents. Thiamethoxam, pymetrozine, lambda-cyhalothrin and acetamiprid showed sustained control efficacy against wheat aphids (>85% at 10 d after application). Azadirachtin had slower initial action but good persistence, reaching 84.14% control efficacy against wheat aphids at 10 d after application. 【Conclusion】 Based on the aphid occurrence patterns and resistance levels in the wheat growing area of northwestern Shandong, controlling aphid populations during wheat heading and flowering stages is recommended. Rotational application of pyrethroid, neonicotinoid and pyridine insecticides is advised for wheat aphid management. Given their slower initial action but prolonged efficacy, pyridine insecticides should be applied during the early outbreak stage of aphids.

Key words: Wheat aphids, Sitobion avenae; Rhopalosiphum padi, pesticides, insecticide resistance, field efficacy evaluation