fungus spreading?

[Morningstarorchids]

It may be a lack of Calcium and magnesium, that will effect new growth,and turn it black... I had this happen a few months ago, we had a guest speaker at our monthly meeting and they addressed this issue. I started watering, twice a month with a Calcium and magnesium mix, and it has helped... i'm not seeing my blubs and new foliage turning black as much ..

[D&S Mabel]

I feel your pain! Lost 9 plants this year + a number of new growths to what you are describing - black rot as far as I can tell. The combination on TS Fay, high heat and more rain seemed to really kick it off with a vengence!

In past years, at peak rainy season in late August / early September (also peak hurricane season), I usually would get a small outbreak, losing just very young growths and most always on cat. types - two or three plants would lose parts but the outbreaks were easy to contain.

This year, for the first time, I fought back with chemicals!! I tried THIOMYL Systemic Fungicide which didn't make much of a dent although I have to admit that I tried it after the outbreak started. I also tried Bayer 3-in-1 Insect, Disease and Mite control and that did SEEM to help at least stop the spread.

I think I need to plan ahead next year for these conditions and start applying the systemic fungicide in late July and continue through the season and see what happens. I also need to watch how much rain the plants get and get them to dry out more between soakings. More air movement might be need as well.

Good luck...

[D&S Mabel]

I was suprised at the number of FL growers, from posts here and elsewhere, that suffer through varying degrees of such outbreaks. Maybe we've just accepted it as part of the conditions and expect to lose parts or a whole plant or two from time to time... I don't know. Not at all uncommon though.

[Ross]

Originally Posted by fredr

This fungus stuff is killing me. This spring I repotted and divided practically everything I have. I disposed of all old media and practically made all pots new again. I've been running into what I guess is black rot here and there on new growth. I bought some rather expensive BANROT to spray and even dunk my plants in it. Perhaps it takes a while but I'm still getting die off on new growth as it tunrs black. I have now covered my shade house to protect against the daily rain so that the orchids have a chance to dry out. I use cocohusk or aliflora as medium mixed with charcoal. Sometimes I mix the aliflora with the coconut. I know I just have to keep working this and hate to throw out a plant that has blackrot. I just cut off the affected part down to where it started to grow and hope for the best. Is this accepted policy or is the plant lost? The strange thing is other parts of such an orchid look good. Is the rot at the root level or only in the new growth. Here's a picture of one plant I just photographed. I then cut the bad stem off and have the pot standing on its own under roof. But others ar near other healthy plants. Can they hurt them even though I spray everything?
Note the black shoot on the right and a new good one on the left.
Just looking at the picture, I'm using bark here.

I see a lot of powdery mildew on the right. I think you may have several issues. A good product to try (in the US) is Schultz Garden Safe Fungicide 3 available at all Home Depots - it's a teal colored spray bottle. It contains a small amount of Neem Oil as the active ingedient. Cheaper yet, is to buy Neem Oil and mix it yourself. This is advertized for powdery mildew as well as rots and certain insects. It's very safe to use indoors except if you have pets, you'll want to let leaves dry first.

[fredr]

My oh my, I posted back in July and am getting responses now. In the meantime I still have die-off using banrot regularly. I'm over the disappointment now and simply remove the affected plant after cutting off any black rot to a different area and hope for the best. I also sprinkle some Thiomythl (?) on the plant where I cut and don't water very often. If they die, they die and I'm not going to go crazy over it.

I probably caused the spreading but dunking my orchids into a mixture of fertilizer and banrot. I figured any fungus would die in the banrot but apparently it can spread to other plants that way. I can't imagine what else can cause this problem. as the orchids are under roof. Perhaps it is the extreme heat and humidity we have here but then why doesn't everybody have the problem here in SW FL?
fred