White powdery spots on Hoya, fungus?

12 years ago

Dear All,

I need help with my Hoya rotundiflora. It's small starter plant grown outside on my patio with lots of indirect light, but no sun, and it got white powdery spots on couple of leaves. It started from one spot (looked as denser fuzz on the side of the leaf) and now is definitely spreading. I checked it under microscope and it's not a bug of any sort, just white tiny thread like growth on the surface, spreading mostly on the "fuzz" and clumping where it started first. With naked eye it looks like sprinkle of flour. I moved this plant inside to get it as far as possible from other hoyas and need help with treatment. Any suggestions will be appreciated. Aggie

Featured Answer

mdahms1979

12 years ago

Watering with anything that is not a systemic fungicide will not do anything to help your plant. After having cleaned the leaves off I would just try a sprinkling of cinnamon on the affected areas. Horticultural sulfur is a common control for mildew as well.

Mike

Comments (6)

mdahms1979
12 years ago
I would check if the surface of the leaf is sticky. If you find that the leaf is sticky then a secondary fungal infection is probably what you are seeing, this would be fungi growing on a food source other than the leaf itself. Often times this happens when insects secrete honey dew.
If the leaf is not sticky then I would wash the plant down with warm soapy water and look for any darkened areas. Normally if fungi is infecting the leaf a darkened bull's eye will form at the site of infection, other times a soft wet or hard brown area will form where the fungi has been consuming the plants cells. If you find evidence of this I would take cinnamon and make a paste with water and then pain that onto the affected area. Hydrogen peroxide is also another useful tool to combat both fungal and bacterial rot.

Good luck with your plant.

Mike
Aggie2
Original Author
12 years ago
Thanks Mike!
There is no sticky stuff on the leaf, and at this time there is no visible damage, no spots.;) I will try Hydrogen peroxide and wait!

Aggie
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Aggie2
Original Author
12 years ago
Did some more research and it looks like powdery mildew... Any ideas how to treat it? Can I try watering with diluted peroxide and spray with neem oil?

Aggie
ima_digger
12 years ago
Just wondering how your hoya is doing. I get powdery mildew on some of my african violet leaves. I spray with Schulltz Fungicide 3. It's labeled 3 in 1 (a miticide, fungicide, and insecticide. It works very well on the violet leaves. I've read that milk with equal parts water, and sprayed on plant will also work.
The cause is from warm, humid conditions and no moving air.
Aggie2
Original Author
12 years ago
Ima_digger,

My hoya is OK for now, some leaf damage mostly from my magic potion (cinnamon infused rubbing alcohol) and no mildew! I got it only on H. rotundiflora and this winter has been dry and very windy, some days I had to take hanging pots down so they wont fly away! Actually I have a lot spider mites on plants this year due to dry and warm weather... I guess there is always something trying to damage our plants.
Could you please let me know where you got Fungicide3? I can't find anything with miticide at my local HD and nursery I use, and you are must be just a bit north of me (Miami) so with some luck there is same store down here!