In vitro nematicidal activity of the experimental formulation tequil against Meloidogyne incognita and Heterodera daverti

A trial was conducted in vitro to assess the effectiveness of the experimental formulation Tequil, a blend of plant extracts (100% aqueous extract of Quillaja saponaria, Yucca schidigera and Tagetes spp.), on motility of second-stage juveniles (J2) of the root-knot nematode Meloidogyne incognita and of the cyst nematode Heterodera daverti. The effects of three concentrations (2.5, 5 and 10 ml/L H2O) of Tequil were compared with those of a control and ethoprophos (1.5 ml/L H2O) after different exposure times (2 to 24 days). All concentrations of Tequil suppressed the motility of J2 of M. incognita, throughout the observation period compared to water control, however, the 2.5 ml/L only reduced movement during the first 10 days. Similar effects were observed with H. daverti. For both nematodes, the nematicidal activity increased with the increase of the concentration of Tequil and exposure time. However, ethoprophos was more effective than Tequil during the first 18 days of exposure. Moreover,removing J2 from Tequil solutions after 6 days and transferring them to water for up to 240 h, revealed that a proportion of them resumed motility. This indicates that, at least at the tested concentrations, Tequil, besides a nematicidal activity, has a nematostatic effect.