Artemisia annua compounds have potential to manage root-knot and potato cyst nematodes

Previous in vitro investigation of the nematotoxic effect of Artemisia annua and its main phytochemicals have indicated that this plant can be a potential source of nematicidal products. Following this previous study, the objective of this work was to assess the nematicidal activity of soil treatments with meal and water extract from dry biomass of Artemisia annua on the root-knot nematodes Meloidogyne incognita and M. hapla and on the cyst nematode Globodera rostochiensis in experiments on potted tomato and potato, respectively. Meal was applied at 5, 10, 20 or 40 g kg−1 soil rates, whereas soil treatments with 25, 50, 100 and 250 g L−1 water solutions of the extract were applied either in a single application or splitted into four treatments. Gall formation and multiplication of both M. incognita and M. hapla on tomato roots were significantly reduced by all soil treatments with A. annua meals. Both single and splitted application of A. annua water extract effectively reduced M. incognita population on tomato roots and in the soil. In the experiment on potato, almost all rates of A. annua meal and extract significantly reduced soil population density of G. rostochiensis, without any statistical difference among the two applications. The nematicidal activity of A. annua products on root-knot nematodes resulted not statistically different or even higher than that of the nematicide fenamiphos. A significant increase of growth was always recorded on tomato and potato plants as a side effect of treatments with meal or water extract. Data from these experiments seem to indicate that products from A. annua can be potential candidates for the formulation of new nematicides suitable for a sustainable nematode management, though field trials are still needed for an effective demonstration of a commercial exploitation.