Hi blutayle, First I wanted to say Congrats on getting some very nice hoyas! Great varieties you got. I'm sure you are on your way to become a Hoya addict like most of us here,lol.

I'm not an expert on Fungus...maybe others has more advise.

I do grow some of my Hoyas outside under Palm trees or Oak trees. They get some dappled sun but mostly indirect bright light. Hoyas love rain and humidity, but too much rain along with the high humidity can cause some problems unfortunately. This rainy season, I've actually not had as much rain as you've had...I would say we're still below average for our normal rainfall. I do agree that too much rain mixed with very high humidity is probably what's causing your fungus/bacterial rot problems on some of your hoyas...my guess is the potting mix is most likely staying wet or too moist all the time which is not good for the plants. You've done the right thing by giving them some shelter under an overhang. This is what I've had to do myself when we get more than two days in a row of heavy rain. Hoyas prefer to slightly dry out between watering and don't usually like to stay constantly wet, especially if the potting mix has a lot of Peat.

There is a product that I've used on one of my hoyas that it had some brown spots on it...I attached a link below. I would test a small area, maybe one of the lower leaves to see how it reacts, but this stuff has neem oil so I'm guessing its safe for most plants. but,some hoyas might be more sensitive than others. I do know that when I used it..it had a bloom spur and the buds fell off...so its not good to use when its blooming or has buds on it.

Hopefully, the cinnamon will do the trick for you and you won't have to use anything else. Just let it dry out "slightly"...Imperialis loves water but just don't let it stay too wet...
Good luck with your hoyas!

Nancy

Here is a link that might be useful: Garden-Safe 3 in1 Fungicide

Nancy,
Thanks so much for the quick response. I was a litte wary as to what the hoyas might be sensitive to or not, as I am not that organic with gardening and would chemically treat. I already removed the one big fungii leaf with the fungus and it killed me to do that...such a pretty leaf..lol. I was thinking of Physan 20 like I would use on my orchids but I notice on each variety of hoya, the leaves can be much different. One, paper thin, while the other is almost succulent. I will try a little on one leaf and see. I just can't wait for the humidity to leave...please..just a few more weeks...then I can emerge from my summer garden cocoon and garden like a maniac...thanks again....Joe.