I don't know what books you're reading but the ones I've read suggested to use sugar. And FYI, it is a 'time honored method' people have been doing it for decades. Theres fewer experienced growers that don't use than do use it that I know. And I've never had "odd shaped, copper colored spots breaking out on my leaves" I'm not getting into a 'pissing contest' about this I've said all I have to say about the subject.