The present invention relates to an oil-in-water emulsion, comprising oily globules that include at least one agriculturally active ingredient, in which the oily globules of the emulsion and are coated with a polymeric adsorption layer. The polymeric adsorption layer coating the oily globules includes (1) at least one polymeric surface-active agent having an HLB values in the range of about 16 to about 18, and (2) at least one ionic surface-active agent. The oily globules of the emulsion have mean particle diameter of less than about 800 nanometers, are resistant to Ostwald ripening and are well suited for the treatment of plants. Agriculturally active ingredients that can be used with the emulsion include, pesticides, herbicides, fungicides, mitocides, bactericides and the like. The invention further includes methods of using the inventive oil-in-water emulsions to treat plants and on surfaces adjacent to plants, plant pests or other pests.