Using sulfur evaporators to combat mildew effectively requires a sufficient volume of evaporated sulfur and a good distribution of the sulfur vapor in the greenhouse. The sulfur evaporator with its 100W element provides a sulfur temperature of 190C, with an optimum amount of sulfur being evaporated and with the powerful chimney effect guaranteeing that the sulfur mist is spread in such a way that all the corners, holes and gaps in the greenhouse are reached.