The invention concerns a powder feed composition for use as nourishment for bees and for the prevention and treatment of acariosis, and, in particular, of infestation by Varroa destructor, as well as the relative treatment method, comprising: a) nutritional and tonic ingredients, mainly consisting of sugars, lower organic acids, powdered milk and/or algae containing vegetal proteins and yeasts； sugars and lower organic acids； b) natural antioxidants and antiseptics with high activity, contained in the extracts of Crocus sativus, Pelargonium graveolens, Monarda citriodora, Myristica fragrans, Origanum vulgare, Origanum majorana； and c) substances medicinal to bees, comprising at least one of thymol and extracts of Thymus vulgaris, and at least one of oxalic acid, extracts of Aloe vera or Aloe arborescens, geraniol and extracts of Beta vulgaris cv. altissima, and mixtures of two or more of the same.
