I discovered scale on one of my cane begonias this morning. It's been in the middle of several others in a light garden for close to a month. I started tearing off the leaves and squashing the the scales but the begonia will be bare by the time I finish. Does anyone know of a systemic that can be used on the other plants and should I try to save this begonia or just try for a few cleaned cuttings? It's a very leafy plant, or it was!