Evaluation of plants with nematicidal properties in the control of Xiphinema index on table grapes cv. Thompson Seedless in the central zone of Chile

The ectoparasitic nematode Xiphinema index Thorne and Allen is economically important in grapes ( Vitis vinifera L.) in Chile, both as a root parasite and as a vector for grapevine fan leaf virus (GFLV). The traditional methods for nematode control are based on chemical nematicides, which are erratic and very questionable for their environment effects. The objective of this research was to evaluate the nematicidal effect of eight antagonistic plant species for controlling Xiphinema index on grapevines cv. Thompson Seedless. The selected plant species were Tagetes patula , Cosmos bipinnatus , Zinnia elegans , Gaillardia picta , Calendula officinalis , Thymus vulgaris , Brassica napus and Lupinus albus . The effect of these plants were compared with three controls: an absolute control without test plants; the nematicide fenamiphos (4 kg a.i. ha -1 ), and barley ( Hordeum vulgare ) as a non-nematicidal plan. The nematicidal action of the sampled species was evaluated determining the nematode population densities in 250 cm 3 of soil: 1) previous to sowing of cover crops; 2) previous to plant incorporation into the soil; 3) three months after the incorporation. The best results were obtained from growing and incorporating Brassica napus, which significantly reduced X. index populations (P<0.05) in comparison with the chemical control (fenamiphos). The rest of the plant species were not effective in the control of X. index