NOVELTY - N-(4-perfluoroalkyl-phenyl)-4-triazolyl-benzamide compounds (I) and their salts or N-oxides are new.    USE - (I) is useful for controlling pest, preferably insects, acarines, and nematodes or molluscs (claimed). (I) is useful for controlling infestations of insect pests such as e.g. Lepidoptera, Diptera, Hemiptera, Thysanoptera, Orthoptera, Dictyoptera, Coleoptera, Siphonaptera, Hymenoptera and Isoptera, other invertebrate pests, Myzus persicae (aphid), Aphis gossypii (aphid), Aphis fabae (aphid), Lygus spp. (capsids), Dysdercus spp. (capsids), Nilaparvata lugens (plant hopper), and Nephotettix cincticeps (leafhopper). The insecticidal activity of 2,6-dimethyl-4-(heptafluoroprop-2-yl)phenyl (200 ppm) to control Heliothis virescens (tobacco budworm) was tested in egg (0-24 hours old). The results showed that the percentage of control of H. virescens was 80%.    ADVANTAGE - (I) has improved insecticidal properties such as improved efficacy, and selectivity. (I) is readily biodegradable. The composition provides: slow and controlled release of (I) to the seed treatment; and improved wetting, retention or distribution on the surfaces, resistance to rain on treated surfaces, or uptake or mobility of (I).    DETAILED DESCRIPTION - N-(4-perfluoroalkyl-phenyl)-4-triazolyl-benzamide compounds of formula (I) and their salts or N-oxides are new.    X1 = NO2, NH2 or amine group having structure of formula (R1-NH-) or (-N(R1)-C(G1)(Q1));    G1, G2 = O or S;    Q1 = aryl or heterocyclyl (both optionally substituted by 1-5 of R3 substituents);    R1, R2 = H, 1-8C alkyl, 1-8C alkylcarbonyl or 1-8C alkoxycarbonyl;    R3 = halo, CN, N, 1-4C (halo)alkyl or 1-4C (halo)alkoxy;    Q2 = phenyl group of formula (II);    Y1, Y5 = halo, CN, 1-4C (halo)alkyl, 1-4C (halo)alkoxy, 1-4C alkoxy-1-4C alkyl, 1-3C (halo)alkylthio, 1-3C (halo)alkylsulfinyl or 1-3C (halo)alkylsulfonyl;    Y3 = 2-6C perfluoroalkyl, 2-6C perfluorocycloalkyl, hydroxy-2-6C perfluoroalkyl, 1-4C alkylcarbonyloxy-2-6C perfluoroalkyl, 1-4C haloalkylcarbonyloxy-2-6C perfluoroalkyl, 1-6C perfluoroalkylthio, 1-6C perfluoroalkylsulfinyl, 1-6C perfluoroalkylsulfonyl, arylcarbonyloxy-2-6C perfluoroalkyl or arylcarbonyloxy-2-6C perfluoroalkyl, where the aryl group may be substituted by 1-5 of R4 groups;    Y2, Y4 = H, halo or 1-4C alkyl; and    R4 = halo, CN, N, 1-4C (halo)alkyl or 1-4C (halo)alkoxy.    An INDEPENDENT CLAIM is included for an insecticidal, acaricidal, nematicidal or molluscicidal composition comprising (I) together with a diluent or carrier.