In vitro nematicidal activity of aqueous plant extracts on Chilean populations of Xiphinema americanum sensu lato

In a search for alternatives to chemicals in nematode management, the nemat icidal activity of 30 plant species (9 native and 21 naturalized in Chile) was tested on a Chilean population of Xiphinema americanum sensu lato, an e conomically important pathogen in grapevine. Aqueous extracts were tested i n a standard concentration (S) at 1:4W/V of fresh plant material, or 1:20 W /V of air-dried plant parts; and 21 plants, were also tested at 25% of S. D istilled water was used as the control. Nematicidal activity was evaluated bs nematode immobility after 24-48 h of immersion in the extracts, followed by 24 h in distilled water. At the standard concentration, all the extract s showed nematicidal or nematostatic activity after 24 h of exposure, but t his effect decreased in the dilute treatment of 33% of the extracts, mostly top extracts. Nematode immobility seas observed at 25% of S, after 24 h, w ith plant extracts in 18 out of 21 plant species including: Tagetes erecta, T. patula nana and Zinnia elegans (tops and roots); Asparagus officinalis, Brassica campestris, Calendula officinalis, Melissa offcinalis, Plantago m ajor, Ruta graveolens (roots); Thymus serpyllum (leaves); and the native Ch ilean plants Aristotelia chilensis (leases); Cestrum parqui (bark); Oenothe ra affinis, Oxalis rosea, Stachys albicaulis (whole plants); Quillaja sapon aria (leaves and flowers); and Vestia lycioides (top). After 48 hoof exposu re, nematode immobility was observed at 25% of Sin Chenopodium ambrosioides (top and root) and M. officinalis (top). These results confirm earlier rep orts on nematicidal properties of the 30 plant species tested. Some of thes e plants could have practical application in the management of Xiphinema in vineyards.