Solidago canadensis extract fractionation, phytochemical identification, and nematicidal/nematistatic activity against Meloidogyne incognita

The development of eco-friendly pest management strategies is crucial for sustainable agriculture. In this study, we investigated the bioactivity of Solidago canadensis leaf extract against Meloidogyne incognita juveniles (J2). In vitro assays showed that aqueous extracts exhibited greater nematistatic (immobilizing) activity than less polar solvent extracts. Fractionation of the aqueous decoction extract using column chromatography yielded 11 fractions (F), which were evaluated at 100, 200, and 300 mg L^- 1. The crude extract showed 100% nematistatic activity at all concentrations, while among the fractions, F5, F7, and F9 were the most effective. In the pot experiment, the crude extract and F7 reduced gall formation by 55.3%, whereas F8, despite low in vitro nematistatic activity (21.5%), achieved the highest gall reduction (58.7%). Unexpectedly, some fractions increased gall formation. GC-MS analysis of F7 and F8 revealed 20 phytochemical compounds, including several with reported nematode-suppressive properties. These findings underscore the potential of S. canadensis extracts and specific fractions as botanical nematistatic agents and emphasize the importance of combining the in vitro and pot bioassays when evaluating botanical nematicides.