The motility and the chemotactic response towards plant roots of Radopholus similis, after treatment with novel types of lectins, were examined in vitro by analysing movement tracks on agar plates. Six plant lectins belonging to five different lectin families and a banana thaumatin-like protein (BanTLP) were included in the experiment. A 1% concentration of Phaseolus vulgaris agglutinin (PHA) had an adverse effect on the motility of R. similis females: 63% showed no or very little movement on agar plates compared to an average of 33% for other lectins and 3% for the control treatment. A 0.05% concentration of PHA still reduced the motility of R. similis females by 75%. Concanavalin A and wheat germ agglutinin did not alter the chemotactic response towards plant roots, despite binding of both lectins to R. similis. In contrast, Galanthus nivalis agglutinin (GNA) reduced orientated movement of R. similis towards plant roots. Subsequently, secretions of R. similis were stained with Coomassie Brilliant Blue R. Nematodes treated with GNA produced secretions less abundantly compared to the control treatment and BanTLP. The other lectins in the experiment had variable effects on secretion.