Prevention and Control of Chemical Components from Cigar Yunxue 39 on Root-knot Nematodes

Purpose To investigate the nematicidal activity and control potential of cigar Yunxue 39 chemical components against tobacco root-knot nematodes, providing a theoretical basis for developing botanical nematicides.

Methods Using Yunxue 39 as the experimental material, the chemical components extract were prepared by silica gel column chromatography combined with gradient elution. The mortality rate and egg hatching inhibition rate of second-stage juveniles of Meloidogyne incognita were determined through in vitro immersion assays, identifying the active components. Concurrently, pot experiments were conducted to evaluate the control efficacy of the active components against tobacco root-knot nematode disease, while liquid chromatography-mass spectrometry (LC-MS) was employed to identify the main chemical components.

Results Yunxue 39 active components exhibited significant nematocidal activity. At a mass concentration of 50.000 mg/mL, the lethal concentration 50 (LC₅₀) was 23.020 mg/mL after 72 hours. After seven days, the inhibition rate of egg hatching of M. incognita reached 75.48%. Pot experiment results showed that when the mass concentration of the active components was 46.0 mg/mL, the root-knot control efficacy and relative nematode population control efficacy were 69.00% and 39.20%, respectively, which was comparable to the control effect of 0.50% abamectin treatment. LC-MS analysis revealed that the main nematocidal compounds in Yunxue 39 active components were neonicotinoids, limonoids, chalcones, quercetin, and maleic acid.

Conclusion This study confirms that the active components of Yunxue 39 can effectively control root-knot nematodes in tobacco, demonstrating potential for development as an eco-friendly nematicide.