Hi, this is my dad's Hoya, and i am wondering if anyone can tell me what is going on. Half the leaves look diseased like in the photo, and the other half are lush and green. It also has no problems flowering. Thanks in advance.
And this one.
This is not a disease but instead damage from the sun. The red pigments are the plants way of dealing with bright light but the dry papery areas show where the cells have ruptured and died. You could move the plant to slightly less light but the reason it flowers well is also due to the light so keep it in bright conditions.
Thanks for the info, Mike, but this plant is kept on a wall that 's all shade. I'll keep an eye on it and shade it a bit more to see if it makes a diffetence. Thanks.
If it's not light then it's possibly heat. The reaction you see, the red pigments, are produced from either bright light or low temperatures. What climate are you in or do you know the night time low temperature when this occurred? Is it possible that the bricks get hot during the day or that for part of the day sun hits the plant? If it's in shade all day then I am not sure of the cause.
The corky growth in the second photo looks different form the damage in the first photo. Is this only on the surface or is it dry and papery all the way through the leaf? There are also fungal scab diseases but I am not aware of any that infect plants from the Asclepiadaceae family that Hoyas belong to.
I think Mike is right. It looks like sunburn damage, so I'm betting it gets some sun, or as he also suggested heat damage from the bricks. I'd put it in a shady spot and see how it does.
Denise in Omaha
Thanks. You may be right, as the part thats in the most shade looks the greenest.But i think it may also have some kind of bug as it has white sticky fluffy bits along the branches and i saw some sort of white bug crawling on it but didnt manage to get a photo. i will put up a photo of the white stuff when i can get to te computer.
The white stuff sounds like Mealy bugs. If you make a solution of Palmolive dish soap and spray the plant every couple of days for a week it should take care of them. To male the solution just fill a spray bottle with water and then add a squirt of soap. Spray all surfaces of the plant and repeat if you notice pests again. If there are larger fluffy areas they are likely egg masses so it's best to wipe those off the plant and then spray with the soap solution.
Thanks for that Mike. sounds easy enough. Will try it :-)