Soft grey brown areas appear on on stored onions. Ensure that lifted onions have dried out thoroughly on the ground before storing to avoid storage problems. Lifted onions could be placed on wire racking to ensure drying conditions. Once dry the onions can be strung up and kept in a light dry place. Ensure there is good air circulation in the store. As soon as anything shows signs of rotting, remove from the store.
There is currently no chemical registered for the control of this problem.