I used Actinovate on my rusty daylilies in May and again last month, and have seen no new rust on them, or the Cannas or the plumeria or the fig tree! This stuff is a bit pricey but it really works. It's a biologic, and actually feeds off the fungus.
The score's not in yet on whether it can keep the black rot fungus at bay on the orchids, but even just for the rust, it's worth it to me.
