Abstract: The present invention relates in a first aspect to a spray formulation. In particular, said spray formulation is a spray formulation adapted for colonisation of plants with spores of endophytes, in particular, entomopathogenic endophytes. The spray formulation according to the present invention includes a surfactant, an UV-protecting compound, a nutrient and spores of the endophytes. In another aspect, the present invention relates to the use of said spray formulation in plant protection, in particular, crop plant protection, and control of plant pests and plant pathogens. Moreover, a method of preventing or treating infestation of plants with plant pests or plant pathogens, is provided comprising the step of applying a spray formulation according to the present invention onto the plants or a part of the plants. Finally, a kit is provided comprising spores of endophytes and a spray formulation as defined herein.