Solvent formulations under EC form comprising (% by weight):10-40% of one or more compounds having an insecticidal activity selected among those of the organophosphate class, comprising the following group (formula (I)):wherein:L1 is selected between oxygen and sulphur,L2 and L3, equal to or different from each other, are selected from oxygen, sulphur or a NH group,with the proviso that at least one from L1, L2 and L3 is sulphur and at least one from L1, L2 and L3 is oxygen,M is selected from oxygen, sulphur or NH；1-20% of an additive formed of methyl or ethyl esters of fatty acids having a C10-C20 chain, saturated or unsaturated, or mixtures thereof, the fatty acids deriving from vegetal oils；3-15% of one or more surfactants selected from non ionic and anionic surfactants, or thereof mixtures；the complement to 100% being one or more organic solvents having the following characteristics:capable to solubilize the active principle, expressed as % by weight, at room temperature (20-25° C.) for at least 5%； preferably 10%, more preferably at least 20%,substantial immiscible with water.
