Natural products in phytomedicine: nematicides from plants

Overuse of synthetic pesticides has generated several environmental problems and health concerns which have led to their progressive withdrawl from the European market. Reasons are related to the high toxicity of these type of biocides, their nonbiodegradable properties with high persistence in soil, water resources and foodcrops. As an alternative to synthetic pesticides, the use of phytochemicals for pest control is a very promising tool in phytomedicine. Management of phytoparasitic phytonematodes affecting the yield and quality of important food crops is of economic importance and in the recent years the interest in the application of botanical nematicides has been enormously growing. We will here describe our latest results on the nematicidal effects of selected chemical constituents such as phenolics, glucosinolates, and terpenes from Asteraceae, Lamiaceae and Brassicaceae plants, against the highly crop destructive root-knot nematode Meloidogyne incognita and the ectoparasite dagger nematode Xiphinema index. Results obtained from in vitro and in soil/pot experiments suggest that the biocidalactivity of these phytochemicals mainly depends upon their chemical features and their individual concentration in the plant extracts. Structure-activity relationship of the most active phytochemicals is also discussed. In conclusion, data here described indicate that plants can be a large source o fbotanical nematicides and that specific specialized metabolites are potentially suitable to develop new nematicides sustainable to environment and human health.