A benzoyl urea compound having the formula:
wherein X is a halogen atom, a nitro group or a trifluoromethyl group, provided that when Y is a nitro group, X is a halogen atom or a nitro group, Y is a hydrogen atom, a halogen atom, a nitro group or a trifluoromethyl group, Z₁ is a halogen atom or a trifluoromethyl group, Z₂ is a hydrogen atom or a halogen atom, and A is a =CH- group or a nitrogen atom, or the formula:
wherein each of X₁ and X₂ is a hydrogen atom, a halogen atom or a nitro group, provided that when Y is a nitro group, X₁ is a hydrogen atom, Y is a hydrogen atom, a halogen atom, a nitro group or a trifluoromethyl group, and Z is a hydrogen atom, a halogen atom or a trifluoromethyl group, characterized in that its average particle size is not larger than 1 µm.