I have scales on my cat palm and I tried what you said. Did not kill them, so I took the next step and took my plant out of the pot and put it in my bath tub with hot (not boiling hot) water, soap, and rubbing alcohol. Left it there for 3 days and washed it. I got new dirt and washed the pot. I see that I killed a lot of them, but I still have them. So I am thinking about cutting all the leaves off beside the ones that did not open to get the pests gone. I don't want them to get to my other plants. What do you think I should do?
Certified GKH Gardening Expert
Try treating the plant with neem oil. I have wonderful success with neem oil and houseplant pests. Here is more information: