(FR2914822) 1. Use of a compound of formula I below entering a plant health composition, for the protection of the plants: (0-12) 3N1-12 R NR..... Formula I in which R is a chain alkyl comprising 8 to 22 carbon atoms, in order to neutralize and/or control and/or kill out of the nematodes, the bacteria and/or mushrooms and/or the mushroom spores and/or the viruses and/or the viroides, likely to damage the aforementioned plant. 2. Use according to claim 1, characterized in that the aforementioned compound is associated with at least a dampening agent. 3. Use according to one of the preceding claims, characterized in that the aforementioned dampener includes/understands a mixture at base - of surfactant as for example a polyalkylglucoside of formula where R corresponds to a chain linear or ramified alkyl and X lies between 5 and 13, - and/or of one sequestering such as for example a phosphonate, such as the sodium salt of the acid diethylene-triaminepenta (methylenephosphonic), - and/or of one cosolvent such as for example an aliphatic alcohol, such as - and/or of one coadjuvent such as for example of an oxide of amine. 4. Use according to claim 3, characterized in that the aforementioned dampener includes/understands 0% to 85% of a polyalkylglucoside, from 0% to 5% of a phosphonate, from 0% to 25% of an aliphatic alcohol and from 0% to 87% of an oxide of amine, in weight, compared to the total weight of known as wetting. 5. Use according to one of the preceding claims, characterized in that the plant health composition includes/understands in % volume to 50% of composed of formula I, 1% to 20% of the alkylpolyglucoside, 0,01% to 1% of phosphonate, 0,5% to 5% of aliphatic alcohol 5. and 0,5% to 10% of oxide of amine compared to the total volume of the plant health composition. 6. Use according to one of the preceding claims, characterized in that the aforementioned compound of formula I and/or the surface-active agent presents in the form of a solution or of an aqueous suspension or in solid form. 7. Use according to one of the preceding claims, characterized in that the aforementioned compound of formula I and/or the surface-active agent is put in solid form by contact with a selected solid support among: silica powder precipitated, kieselgur, ground of diatoms, powder clays, zeolites, or other materials porous or their mixtures. 8. Use according to one of the preceding claims, characterized in that the nematodes on which the compound acts according to formula I are selected among: cecidogenous nematodes, such as Meloidogyne spp. nematodes with cyst such as Globodera spp. Heterodera spp. radicicolous nematodes such as Pratylenchus spp. nematodes of the citruses such as Tylenchulus semipenetrans, the Trichodorus nematodes such as Trichodorus spp. nematodes with lancet such as Longidorus spp. Hopoloaimus spp. nematodes with stylet such as Paratylenchus spp. the nematodes reniformes such as Rotylenchulus spp. the Xiphinema nematode such as Xiphinema spp. the Belonolaimus nematodes such as Belonolaimus spp. nematodes ringed such as Criconemoides spp. Criconemella spp. the Tylenchorhynchus nematodes such as Tylenchorhynchus spp. spiral nematodes such as Rotylenchus spp. Helicotylenchus spp. the Radopholus nematodes such as Radopholus similes. 9. Use according to one of the preceding claims, characterized in that the bacteria on which the compound of formula I acts are selected among: Pseudomonas such as Pseudomonas syringae statement lacrymans, Pseudomonas syringae statement phaseolicola, Pseudomonas aeruginosa; Clavibacter such as Clavibacter michiganesis michiganensis; Staphylococcus, such as Staphylococcus aureus; or Xanthomonas such as Xanthomonas camp estris statement vesicatori or campestris; Agrobacterium tumerfacians; Agrobacterium rhizogenes. 10. Use according to one of the preceding claims, characterized in that the mushroom mushrooms and/or spores on which the compound of formula I acts are selected among: Armillaria, Aphanomyces, Botrytis such as Botrytis cinerea, Fusarium, Geltrichum such as Geltrichum candidum, Helminthosporium, Mildew, Monosporascus, Mucor spp. Penicilium such as Penicillium digitatum, Penicillium expansum, Penicillium italicum, Penicillium rockfortii, Phytophthora, Phytomaototricum, Postia, Pythium, Rhizoctonia, Sclerotinia, Verticillium. 11. Use according to one of the preceding claims, characterized in that the viruses and/or the viroides on which the compound of formula I acts are selected among: Bromoviridae, Closteroviridae, Comoviridae, Geminivirus, mosaic Virus, Potyviridae, Sequiviridae, Tom busviridae, Tymoviridae, Badnavirus, Carlavirus Luteovirus, Nanovirus, Phycodnaviridae, Potexvirus, Tenuivirus, Tospovirus.