Nematicidal activity of the alpine medicinal plant Peucedanum ostruthium against the root-knot nematode Meloidogyne incognita

Restrictions on the use of chemical pesticides have raised growing interest in the study of plant-derived nematocidal compounds. The potential nematocidal properties of Peucedanum ostruthium (Apiaceae) were tested by 2% ethanol plant extracts in vitro and in pot experiments. Infective juveniles (J2s) were exposed for 4, 8, 24, 48 and 96 h to 62.5, 125, 250, 500, 1000 and 2000 μg mL-1 concentrations of both root and leaf extracts, including distilled water and a chemical nematicide as controls. Nematode mortality reached more than 98% after 24-hour treatment with 500, 1000 and 2000 μg mL-1 solutions of root extract and 94% after 48-hour treatment with 1000 and 2000 μg mL-1 solutions of leaf extract. To assess the ability to infect, juveniles were exposed for 24 h to the LD50 of both extracts, then rinsed and inoculated in tomato plants kept in growth chamber. Thirty days after inoculation, nematode infection was significantly reduced in roots inoculated with root extract treated J2s. The suppressiveness of P. ostruthium extracts was also investigated by irrigating tomato plants in 50 mL pots with 5 mL of 4000 μg mL-1solutions at inoculation and 2 weeks later. At the end of nematode life cycle, infestation on tomato roots was reduced and, particularly, a significant reduction of the eggs/egg mass numbers was observed. Results from this study show a high nematocidal potential of P. ostruthium root extract, which can be eexploited forthe formulation of new effective nematicides.This study was funded by PNRR Agritech, task 3.2.5 ‘Nature-based solutions for natural resources and environment protec-tion’.