Already have safers soap (I assume he means Safer brand insecticidal soap). I tired that, and still it didn't work.
I bought the soap concentrate that you mix with water. I was using the recommended mix, spraying twice a week for a month. Would your dad know if I can increase the concentration or frequency? I was thinking of trying a strong spray daily for two weeks to see what happens. I was also thinking of cutting off all the leaves on the PLumeria which is ok for them, but I think the biggest problem is the hibiscus. It's 5 feet tall and got 100's of leaves, so it's really hard to spray.
I was actually thinking of getting one of those large mist pump sprayers and filling it up, since I have so many large plants (each plumeria is a 3 foot tall, 3 foot wide tropical type plant with large flat leaves), it would be easier than a small bottle, and I can just put them all in the tub and seriously coat them well.
Something like this: