Tobacco–peanut rotation enhances suppression of peanut aphids and increases peanut yield via residual nicotine in soil

BACKGROUND: Tobacco-peanut rotation is a common agricultural practice in the Shandong region of China. However, its specific benefits for pest suppression and control remain insufficiently investigated. RESULTS: The abundance of Aphis craccivora was significantly reduced under the tobacco-peanut (TP) rotation than under the peanut-peanut (PP) monoculture. Compared with the PP system, aphid abundance in the TP system on the peak dates (5 July 2024 and 9 July 2025) was reduced by 96.3% and 92.3%, respectively. Nicotine concentrations in both soil and peanut foliage were significantly higher in TP systems than in PP systems. Additionally, nicotine levels in peanut leaves under TP exhibited a progressive and significant increase throughout the growing season. Peanut leaves from the TP fields exhibited strong deterrent effects against Aphis craccivora, with stronger repellency at higher nicotine concentrations. Aphid survival on TP leaves was significantly lower than on PP leaves and exhibited a clear dose-dependent response. Moreover, the peanut pod maturity index and yield were significantly higher in TP fields than in PP fields, with peanut yield in TP fields being 12.8% higher than in PP fields. CONCLUSION: In TP rotation systems, the allelochemical nicotine is exuded from tobacco roots into the soil, subsequently absorbed by the following peanut crop, and ultimately enhances aphid resistance. The findings highlight the value of optimized crop rotations within integrated pest management (IPM) frameworks. © 2026 Society of Chemical Industry.