The device allows continuous and repeated cycle execution of diffusion by sublimation, of oxalic acid dihydrate inside Beehives. New electronic PID system with thermocouple for automatic management and constant temperature maintenance. Realizes complete sublimation of oxalic acid powder by constant boiler temperature. Easily transportable, allows through connection to a power generator or directly to 220V mains or inverter 12V ->220V allows operation in any environment. Safe, reliable and easy to operate due to process isolation in the boiler that prevents contact with fumes. Built according to CE standards and already patented at international bodies Warranty 1 year.