A hydrophilic formulation of the inert silicate kaolin was tested in a screenhouse for its effect on the behavior of the root weevil Diaprepes abbreviatus (L.), a pest of citrus and ornamental plants in Florida and the Caribbean. Feeding by adults on treated foliage was reduced by 68-84% compared with adults fed untreated foliage. No insecticidal activity was detected after 14 d of exposure to kaolin-treated leaves. Oviposition was completely suppressed on treated foliage. Although females oviposited >19,000 eggs during two trials on untreated foliage, no egg masses were found on foliage treated with the kaolin formulation. These data indicate potential for kaolin as a barrier to oviposition in citrus groves and may prove to be an economically viable and environmentally sound component of an integrated approach for control of D. abbreviatus and related root weevils.