Compositions which contain, as the active ingredients, a combination of heterocyclic compounds of the general formula (I) and organophosphorous compounds, in addition to one or more compounds having a polyethyleneglycol or polypropyleneglycol chain or an ethyleneglycol-propyleneglycol copolymeric chain, or a mixture of these compounds which results in a stabilization of the active ingredients without any adverse influences on the physical properties of the formulations.

Compositions which contain, as the active ingredients, a combination of heterocyclic compounds of the general formula (I) and organophosphorous compounds, in addition to an amorphous silica additive selected from the class consisting of: (a) an amorphous silica obtained by a process, wherein an amorphous silica hydrate, which has been produced by a wet synthetic, method, is either silylated or heated to effect an etherification so as to decrease the surface silanol radicals of the amorphous silica hydrate, and (b) an anhydrous, amorphous silica obtained by a dry synthetic method, or a silylated derivative thereof, and optionally one or more compounds having a polyethyleneglycol or polypropyleneglycol chain or an ethyleneglycolpropyleneglycol copolymeric chain, or a mixture of these compounds which results in a stabilization of the active ingredients without any adverse influences on the physical properties of the formulations.

An insecticidal composition comprising (i) a compound of the formula ##STR1## wherein A is hydrogen, alkyl or a divalent group connected to B, B is alkyl, ##STR2## or a divalent group or atom connected to A, R is hydrogen, acyl, alkyl or optionally substituted heteroarylalkyl, Y is ##STR3## T.sup.1 is hydrogen or optionally substituted alkyl, and X is an electron attractive group, and (ii) a synergistically effective amount of a methylenedioxybenzene derivative.

Compositions which contain, as the active ingredients, a combination of heterocyclic compounds of the general formula (I) and organophosphorous compounds, in addition to one or more compounds having a polyethyleneglycol or polypropyleneglycol chain or an ethyleneglycol-propyleneglycol copolymeric chain, or a mixture of these compounds which results in a stabilization of the active ingredients without any adverse influences on the physical properties of the formulations.

A coating composition comprising a first phase containing a cross-linkable resin; a second phase containing water; and a third phase containing an insecticide dissolved in a solvent wherein the solvent is immiscible with the first phase and with water. These coating compositions kill insects even after exposure to weather for extended periods of time. They have kill rates higher than prior art compositions containing the same amount of the same insecticide.