Evaluation of in vitro nematocidal effects on Meloidogyne incognita of laboratory extracted and commercial essential oils of Artemisia annua

Root-knot nematodes, Meloidogyne spp., are considered the most harmful nematodes because of their worldwide occurrence and heavy yield losses caused to a large range of crops. In the last two decades, many experiments have been conducted using essential oils (EOs) against different genera of plant parasitic nematodes. Sweet wormwood, Artemisia annua shows great potential of application to produce new nematocidal products due to the presence of a high number of bioactive phytochemicals. The aim of this work is to evaluate the effects against M. incognita of laboratory extracted and commercial EOs of A. annua collected from different geographical locations. One EO extracted from dried leaves of A. annua from South Italy and one commercial EO purchased from India were tested on juveniles (J2s) of M. incognita. J2s were exposed for 24 and 48 h to 1000, 2000 and 4000 μg mL-1 concentrations of both EOs in an orbital incubator at 70 rpm, at 25 °C. J2 mortality caused by the lab-extracted EO was about 18% at 4000 μg mL-1 concentration after 24 h, and 44% after 48 h. J2 mortality caused by the commercial EO was 38% at both 1000 and 2000 μg mL1 after 24 h, and 48% at 2000 μg mL-1 after 48 h. Our findings show that the activity profiles of Artemisia EOs could be associated with distinct phytochemical compositions, different geographical origin and season of collection. The chemical profiles of the EOs and the molecular mechanisms they trigger in J2s are being studied