A composition having a pesticide and a hydroxyalkyl polyoxylene glycol ether of the general formula (I) where R1 is a saturated or unsaturated, linear or branched alkyl having 6 to 18 carbon atoms; R2 is ethylene, propylene, butylene or a mixture thereof; R3 is a saturated or unsaturated, linear or branched alkyl having 6 to 18 carbon atoms; and n has a value of from 1 to 100. The composition may be used as an adjuvant in in pesticide-comprising spray mixtures. In a method for controlling phytopathogenic fungi and/or undesirable plant growth and/or undesirable insect or mite infestation and/or for regulating the growth of plants, the composition is allowed to act on the respective pests, the habitat thereof or the plants to be protected from the respective pest, on the soil and/or on undesirable plants and/or the crop plants and/or the habitat thereof. Seed may also include the composition.