Effects of tobacco–rice rotation on rice planthoppers Sogatella furcifera (Horváth) and Nilaparvata lugens (Stål) (Homoptera: Delphacidae) in China

Background and aim Tobacco–rice rotation is a useful traditional practice for controlling crop diseases and pests. However, its effect on rice pests has not been studied. We aimed to clarify the ecological effect of tobacco–rice rotation on two destructive rice pests Nilaparvata lugens (Stål) and Sogatella furcifera (Horváth). Methods Populations of rice planthoppers N. lugens and S. furcifera in rice–rice successive cropping (RRSC) and tobacco–rice rotation cropping (TRRC) paddy fields were counted using large white plates. The nicotine concentration of soils, rice plants (divided into leaves, stems, roots and panicles) collected from TRRC and RRSC fields were quantitatively analyzed using the LC-MS/MS technique. Results There was a large and significant difference between TRRC and RRSC systems in total number of rice planthoppers. Moreover, the nicotine concentrations of soils and in rice (roots, stems and leaves) in TRRC were significantly higher than those in RRSC, especially in roots the concentration was 1000 times higher, but there was no significant difference in concentration in rice panicles. Conclusion This study suggests that nicotine uptake by rice roots, from soil containing tobacco residues in the TRRC system, affected the abundances of S. furcifera and N. lugens .