A method of reducing damage to plant propagation material and plant organs which grow at a later time by a representative of the class Nematode, which method comprises (I) treating the propagation material with (A) a chelating agent, and optionally (B) a macrocyclic lactone compound or another pesticide, before the material is sown or planted, or (II) applying (A) a chelating agent, and optionally (B) a macrocyclic lactone compound or another pesticide, to the locus of the material or the treated material defined in (I) before its planting, and/or at its planting and/or during its growth.