(WO2008129218) 1. Use of a compound of formula I below entering a plant health composition, for the protection of 5. 5. Plants:[Q]Formulate 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, des5 bacteria and/or of mushrooms and/or the mushroom spores and/or the viruses and/or the viroides, likely to damage the aforementioned plant. 2. 2. Use according to claim 1, characterized in that the aforementioned compound is associated with at least a dampening agent. 3. 3. Use according to one of the preceding claims, 0 characterized in that the aforementioned dampener understands a mixture at base: - of surfactant such as for example a polyalkylglucoside of formula R-O- [C H θ (OH) ] - CH - O ([C H O (OH) ] - CH - O) [X] - H, where R corresponds to a chain linear or ramified alkyl and X est5 ranging 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, tel0 that CH CHOHCH OH, - and/or of one coadjuvent such as for example of an oxide of amino. 4. 4. Use according to claim 3, characterized in that the aforementioned dampener understands 0% to 85% of a polyalkylglucoside, of 0 % with 5% of a phosphonate, 0% to 25% of an aliphatic alcohol and de5 0% to 87% of an oxide of amino, in weight, compared to the of the aforesaid total weight wetting. 5. 5. Use according to one of the preceding claims, characterized in that the medical phyto composition understands in volume 5% to 50% of the compound of formula I, 1% to 20% of the alkyl- polyglucoside, 0,01% to 1% of phosphonate, 0,5% to 5% of aliphatic alcohol and 0,5% to 10% of oxide of amino compared to the total volume of the plant health composition. 6. 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. 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. 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 Meloidogynous spp., the nematodes with cyst such as Globodera spp., Heterodera spp., the radicicolous nematodes such as Pratylenchus spp., the nematodes of the citruses such as Tylenchulus semipenetrans, the Trichodorus nematodes such as Trichodorus spp., the nematodes with lancet such as Longidorus spp., Hopoloaimus spp., the 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., the nematodes ringed such as Criconemoides spp., Criconemella spp., the Tylenchorhynchus nematodes such as Tylenchorhynchus spp., the nematodes spirals such as Rotylenchus spp., Helicotylenchus spp., the Radopholus nematodes such as Radopholus similes. 9. 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 campestris statement vesicatori or campestris; Agrobacterium tumerfacians; Agrobacterium rhizogenes. 10. 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., Penicillium such as Penicillium digitatum, Penicillium expansum, Penicillium italicum, Penicillium rockfortii, Phytophthora, Phytomaototricum, Postia, Pythium, Rhizoctonia, Sclerotinia, Verticillium. 11. 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, Tombusviridae, Tymoviridae, Badnavirus, Carlavirus Luteovirus, Nanovirus, Phycodnaviridae, Potexvirus, Tenuivirus, Tospovirus.