The invention relates to the pre- or post harvest fungicidal and/or bactericidal treatment of plant products, using at least phosphonic acid that is at least partially salified and eugenol or clove oil, at ambient temperature, as well as to the compositions suitable for said method.本発明は、常温で、少なくとも部分的に塩化した少なくともホスホン酸及びオイゲノール又は丁子油を用いる、植物製品の収穫前又は収穫後の殺真菌及び/又は殺細菌処理に関し、並びに、前記した方法に適した組成物に関する。