The invention relates to an insecticidal water- in- oil (W/O) formulation , comprising at least one insecticidal active ingredient and at least one burning salt, and the production of said formulation. The formulation according to the invention is suitable in particular for treating suitable carrier materials, in particular paper carriers , in an economical single -step process by means of conventional application methods. The present invention further relates to insecticidal products that can smolder , which are produced by treating a carrier material with the formulation according to the invention.
