Some Misunderstanding With a Kentia Palm
I have recently bought a Kentia palm that is 1. 7 meters high. Now what interests me is the black stains I can see on its trunk. I'm very worried about it and have no clue why is that and what to do. I took some pictures:
Certified GKH Gardening Expert
It looks like the plant certainly has powdery mildew, which is a fungus and can be treated with a fungicide.
It looks like the plant may also have scale, which would cause the black spots. This needs to be treated with a pesticide.