1. A nematicidal agent containing at least one compound of formula (I) in which B is 2-pyridyl, 3-pyridyl or 4-pyridyl, X is selected from the group consisting of halogen, nitro, cyano, hydroxy, amino, -SH, -SF, -CHO, -OCHO, -NHCHO, -COOH, -CONH, -CONH (OH), -OCONH, (hydroxyimino) -CC-alkyl, CC-alkyl, CC-haloalkyl having from 1 to 5 halogen atoms , CC-alkenyl, CC-alkynyl, CC-alkylamino, di- (CC-alkyl) amino, CC-alkoxy, CC-haloalkoxy having from 1 to 5 halogen atoms, CC-alkenyloxy, CC-haloalkenyloxy having from 1 to 5 halogen atoms, CC-alkynyloxy, CC-halogen alkynyloxy having 1 to 5 halogen atoms, CC-cycloalkyl, CC-halogenocycloalkyl having 1 to 5 halogen atoms, CC-alkylcarbonyl, CC-haloalkylcarbonyl having 1 to 5 halogen atoms, —CONH (CC-alkyl), -CON (CC-alkyl), -CONH (OC-C-alkyl), -CON (OC-C-alkyl) (CC-alkyl), CC-alkoxycarbonyl, CC-haloalkoxycarbonyl having from 1 to 5 halogen atoms, CC -alkylcarbonyloxy, CC-haloalkylcarbonyloxy having 1 to 5 halogen atoms, CC-alkylcarbonylamino, CC-haloalkylcarbonylamino having 1 to 5 halogen atoms, -OCONH (CC-alkyl), -OCON (CC-alkyl), -OCONH ( OC-C-alkyl), - OCO (OC-C-alkyl), -SCC-alkyl, -SCC-haloalkyl having from 1 to 5 halogen atoms, -S (O) -CC-alkyl, -S (O) -CC-haloalkyl having from 1 up to 5 halogen atoms, -S (O) -CC-alkyl, -S (O) -CC-haloalkyl having from 1 to 5 halogen atoms, (CC-alkoxyimino) -CC-alkyl, (CC-alkenyloxyimino) -CC -alkyl, (CC-alkynyloxyimino) -CC-alkyl, (benzyloxyimino) -CC-alkyl, benzyloxy, -S-benzyl, benzylamino, phenoxy, -S-phenyl and phenylamino； n is 1, 2, 3 or 4, and if n is 2, 3, or 4, then X substituents may be the same or different； R and R are the same or different and are selected from the group, incl.1. Нематоцидное средство, содержащее по меньшей мере одно соединение формулы (I)в которойB представляет собой 2-пиридил, 3-пиридил или 4-пиридил,X выбирается из группы, включающей галоген, нитро, циано, гидрокси, амино, -SH, -SF, -CHO, -OCHO, -NHCHO, -COOH, -CONH, -CONH(OH), -OCONH, (гидроксиимино)-C-C
