1. The method of processing plant products before harvesting or after harvest, comprising applying: - phosphonic acid in the form of at least partially converted into salt, essential oil or one of the terpene compounds contained therein and / or mixtures thereof selected from clove oil, thyme, origigan, cinnamon, peppermint oil, and euphenol, isoeuvgenol, L-carvone, thymol, geraniol, carvacrol, cinnamaldehyde and / or mixtures thereof at ambient temperature are used as terpene compounds. 2. The method according to claim 1, wherein the phosphonic acid salt corresponds to the general formula HMPO Where M is a metal atom, such as an alkali or alkaline earth metal, or an ammonium group or an amino group, x is from 1 to 2.8； y is from 0.2 to 2 and x + y = 3.3. The method according to any one of the preceding paragraphs, where the salt corresponds to the formula HMPO, where M is potassium. 4. A method according to claim 1 or 2, wherein the phosphonic acid salt is prepared in advance or prepared in situ in the composition for processing in the presence of an appropriate base. The method according to claim 1 or 2, wherein the essential oil, or one of the terpene compounds contained therein, and / or their mixtures are selected from clove oil or eugenol, isoeugenol, or mixtures thereof. A method according to claim 1 or 2, comprising applying: - phosphonic acid, - a base of an essential oil or one of the terpene compounds contained therein and / or their mixtures at ambient temperature. A method according to claim 1 or 2 for fungicidal and / or bactericidal treatment. A method according to claim 1 or 2 for processing from Phytophtora, Monilia, Penicillium sp, Geotrichum sp, Rhizoctonia, Helminthosporium, Cholletotrichum. 9. The method according to claim 1 or 2, carried out by spraying. 10. The method according to claim 1 or 2, carried out in the garden. 11. The method according to p. 1 or 2, where the sediment1. Способ обработки растительных продуктов перед сбором урожая или
