A gal on one of the facebook iris groups uses Serenade to combat fungal and bacterial problems. It is not an icky chemical. It is a good bacteria that eats the naughty organisms. I think I will get some concentrate and spray it around the garden. She says it prevents leaf spot too. My mallows got spots from being too close to the Bouncing Bets. I don't think it is the same kind though, looks more like apple rust.
