Disclosed are solid forms of 8-chloro-N-[(2-chloro-5-methoxyphenyl)sulfonyl]-6-(trifluoromethyl)-imidazo[1,2-a]pyridine-2-carboxamide (Compound 1). Methods for the preparation of solid forms of Compound 1 and for the conversion of one solid form of Compound 1 into another are disclosed. Disclosed are nematocidal compositions comprising a nematocidally effective amount of a solid form of Compound 1 and at least one additional component selected from the group consisting of surfactants, solid diluents and liquid carriers. Compositions comprising a mixture of a solid form of Compound 1 and at least one other nematicide, insecticide and/or fungicide are also disclosed. Also disclosed are methods for protecting a plant from nematodes comprising applying to the plant, or portion, or seed thereof, or to the growing medium of the plant, a nematocidally effective amount of Compound 1 comprising the polymorph Form A.
