Control of plant-parasitic nematodes with extracts of Quillaja saponaria

Abstract

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((R)) (whole extract containing saponin and non-saponin fractions); ii) QL ULTRA((R)) (saponin fraction); and iii) QL NS(R) (non-saponin fraction). The results showed that QL 1000((R)) had important nematicidal effects at economically attractive doses (e.g., 100 ppm). When used separately, QL ULTRA((R)) and QL NS(R) had minimum nematicidal effects. However, the combined use of both products gave similar results to QL 1000((R)), suggesting a synergy between the saponin and non-saponin fractions. Based on this, QL 1000((R)) was tested in commercial vineyards and table grapes in the Central region of Chile. The use of 301 ha(-1) showed a similar control and fruit yields to synthetic chemical nematicides.