A method for the control of soil-dwelling pests and/or soil-borne diseases comprising treating a plant propagation material with an effective amount of the pesticidal composition and/or applying an effective amount of a pesticidal composition to a locus where control is desired, provided that the composition comprises, as active ingredient, one or more pesticides (A) having a water solubility of at most 100 μg/litre, at 25 °C at neutral pH, and at least one formulation auxiliary, wherein the size of particles in the composition is in the range 3.60 μm to 0.70 μm at X
