Control of plant-parasitic nematodes with extracts of Quillaja saponaria

Aqueous extracts of the tree Quillaja saponaria Molina, containing triterpenoid saponins, polyphenols, salts and sugars, were tested against the most important plant-parasitic nematodes present in Chile: Xiphinema index, X. americanum s.l., Meloidogyne hapla, M. ethiopica, Pratylenchus thornei, Tylenchorhynchus sp., Criconemoides xenoplax and Helicotylenchus sp. Three different products were tested in the laboratory: i) QL 1000® (whole extract containing saponin and non-saponin fractions); ii) QL ULTRA® (saponin fraction); and iii) QL NS® (non-saponin fraction). The results showed that QL 1000® had important nematicidal effects at economically attractive doses (e.g., 100 ppm). When used separately, QL ULTRA® and QL NS® had minimum nematicidal effects. However, the combined use of both products gave similar results to QL 1000®, suggesting a synergy between the saponin and non-saponin fractions. Based on this, QL 1000® was tested in commercial vineyards and table grapes in the Central region of Chile. The use of 30 l ha−1 showed a similar control and fruit yields to synthetic chemical nematicides.