Polyurea microcapsules particularly suitable for foliar application are prepared by an interfacial polymerization process in which the polyurea is formed from an aromatic diisocyanate and optionally an aromatic polyisocyanate having 3 or more isocyanate groups, in a weight ratio (when both types of isocyanate are present) of polyisocyanate:diisocyanate of from about 1:100 to about 1:15, and in which the microcapsules are produced having an average particle size of from about 1 to about 5 microns. As compared to conventional liquid (e.g., emulsifiable concentrate) compositions of pesticides, the microcapsules can provide safer handling and higher loading of active ingredients, while providing substantially equivalent biological activity to the liquid compositions.
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