Objective: The root rot of Panax quinquefolium is related to the allelochemicals produced and secreted by itself

so it is to investigate the correlation between the occurrence of root rot and the accumulation of dencichine(β-N-oxalyl-L-α

β-diaminopropionate

β-ODAP) in P. quinquefolium.Method: Normal and root rot Panax quinquefolium in two to four years of growth with continuous cropping and stubble were collected from Jiashisen planting base

Liuba county

Hanzhong. Precolumn derivatization high performance liquid chromatography (HPLC) with 1-fluoro-2

4-dinitrobenzene (FDNB) was used to determine the content change of β-ODAP in taproot and lateral root of P. quinquefolium.Result: The results showed that the content of β-ODAP in root rot disease was significantly higher than that in normal P. quinquefolium. The accumulation of β-ODAP in continuous cropping samples was significantly higher than that in the stubble samples. The content accumulation of β-ODAP in the normal P. quinquefolium was highest in three years samples

followed by two years samples

and lowest in four years samples. In contrast

the content accumulation of β-ODAP in root rot disease was highest in four years samples

followed by two years samples

and lowest in three years samples. There was significant differences in the accumulation of β-ODAP between the taproot and fibrous root

especially in two years and three years samples.Conclusion: The results showed that the content of β-ODAP in the continuous cropping P. quinquefolium was significantly higher than that in the raw stubble samples

and the content of β-ODAP in the root rot was significantly higher than that in the normal P. quinquefolium. The occurrence of P. quinquefolium root rot was positively correlated with the accumulation of β-ODAP in roots.