Results of discriminating dose tests of red flour beetle indicated that all eight examined strains were resistant to malathion, one strain was resistant to phosphine, and none was resistant to chlorpyrifos-methyl. Similar discriminating dose tests for lesser grain borer indicated that all 21 strains were resistant to malathion, dichlorovs, and to chlorpyrifos-methyl, and eight strains were resistant to phosphine. -from Authors