A compound having the formulawherein:R11 is a member selected from the group consisting of C1-C6 alkyl, aryl- or halo-substituted C1-C6 alkyl, hydroxyl-substituted C1-C6 alkyl, andcarbamoyl C1-C6 alkylR12 is a member selected from the group consisting of H, C1-C6 alkyl, halo-substitutedC1-C6 alkyl, halo, and C1-C6 alkylthio, and R13 is a member selected from the group consisting of H and C1-C3 alkyl, or R12 and R13 are joined to form a thio-C1-C3 alkylene or alkylene linkage, and R14 is a member selected from the group consisting of H and C1-C6 alkyl, and X is CH or N.