Abstract: 【Aim】 To elucidate the effects of Cnidium monnieri on ladybird conservation and aphid control during the whole growth period of wheat and maize. 【Methods】 The occurrence amounts of ladybirds and aphids in wheat and maize fields with C. monnieri planted and the control with pure crops planted were systematically investigated and counted by visual observation throughout the year, and the spatio-temporal correspondence between ladybirds and aphids was clarified. 【Results】 Planting C. monnieri significantly increased the occurrence amounts of natural enemy ladybirds in wheat and maize fields, which in turn significantly reduced the occurrence amount of aphids. In 2020 and 2022, the peak numbers of ladybirds in wheat fields with C. monnieri planted were 25.33 and 9.00 individuals/m², respectively, which were significantly higher than those in the control wheat fields (11.73 and 5.33 individuals/m², respectively). Concurrently, the peak total numbers of aphids in wheat fields with C. monnieri planted were 786.00 and 817.33 individuals/100 plants, respectively, which were significantly lower than those in the control wheat fields (932.67 and 1 133.33 individuals/100 plants, respectively). During the same period, the peak numbers of ladybirds in maize fields with C. monnieri planted were 77.53 and 109.33 individuals/100 plants, respectively, which were significantly higher than those in the control maize fields (50.67 and 77.33 individuals/100 plants, respectively). In 2020, no significant difference was shown in the peak number of Rhopalosiphum maidis in maize fields between treatment and the control. However, on one week after the peak period of R. maidis, the individual number of R. maidis per 100 plants in maize fields with C. monnieri planted was 2 209.33, significantly lower than that in the control maize fields (5 926.67). In 2022, the individual number of R. maidis per 100 plants in maize fields with C. monnieri planted was 13 533.30, significantly lower than that in the control maize fields (30 600.00). 【Conclusion】 Planting C. monnieri in wheat-maize rotation cropping system can conserve natural enemy ladybirds throughout the year, effectively suppressing the occurrence of wheat aphids and R. maidis, thereby exerting a good ecological pest control effect.

Key words: Ladybirds, wheat aphids; Rhopalosiphum maidis, Cnidium monnieri, functional plants, ecological control