Have you tried a spray bottle of water and a little bit of dishwashing liquid??

No- I haven't. I've tried that on other plants, not this one. Is that about a teaspoon of dishwashing liquid to a gallon of water?
Thanks for your help

I dont guess I have ever measured it, I think my spray bottle holds about 28oz and I just put a few drops in of the concentrated stuff. If I had to guess I would say bout an 1/8 to 1/4 of a teaspoon.

Genatac, First, Isolate your Crown of Thorn, ASAP. Keep it away from all other plants.
I spray with soap and water every so often; it keeps mites at bay, but if you have WF infestation, soap and water isn't going to work. Though it doesn't hurt doing spraying to keep other insects away.

You said you used Yellow Sticky Traps? What size are the traps?
The Yellow Traps should be new, the glue fresh. If you used the small traps, (4x6,) since your Crown of Thorns is large, perhaps 2, 3 or possible 4 traps are needed.
You asked if anyone had a similar experience..Yes, I did. My plants are set outdoors every summer. Autumn came, plants were brought back in. While misting, I noticed little white flying insects on a Hibiscus, then another plant and another..BTW, I have over 300 indoor plants, so can you imagine finding these creatures on every single plant? Plants were sprayed with soap/water and a few other ingredients. I don't use chemicals) but nothing helped. What's ironic, I got a catalog in the mail from Gardens Alive a few days before finding the WF. While browsing pages, I discovered, for the first time, Yellow STicky Traps. I was so desparate, I ordered several packs. After they arrived I attached to plants, section by section. 36 traps. Within a week every WF died. The traps were loaded! Each traps filled from end to end. To this day I vouch for Yellow Sticky Traps.
BTW, I found the host plant which caused the infestation. An outdoor, hardy Hydrangea.

If it was my Crown this is what I'd do. First, either take outdoors or hose/shower indoors, spraying all foliage/stems. Tilt the Crown of Thorns so soil doesn't get wet.
Let air dry. In a spray bottle I'd mix soap, Fish Emulsion, (1 capful to a 16 oz bottle of water) garlic and citrus rind. The night before spraying I'd set a clove of garlic in water. In place of citrus rind, lemon juice would suffice. Shake well. Spray thoroughly, all parts of plant, leaves and stems..BTW, I'd spray outside.
I'd then add 3-4 Yellow STicky Traps on plant.
Traps should be yellow, and glue fresh.

If you have time, you can make your own traps..Cut out yellow cardboard or paint yellow. Using Tanglefoot (glue) paste on cardboard strips. Tanglefoot is very strong, probably stronger than Superglue.
But it's easier buying premade Traps. lol. It's important glue is fresh, that traps werent' lying around and glue dried.
After my infestation I purchased more traps in case WF returned. They didn't, but over time the glue dried up, even though traps were sealed.
So, I hope your purchased fresh traps. Are the traps still on your Crown? If so, do you see WF? Since your Crown is/was infested, traps should be filled.
If traps are loaded, replace with new Yellow Traps. Some say these traps are reusable, but in order to reuse you'd need glue. Good luck, keep us posted..Toni

I have a crown of thorns that is about 4 ft tall I put it outside every summer it does great except this year I have something chewing on the leaves none of my other plants are infected just trying to figure out what I can use on it that won't hurt it please help

If spraying with any kind of 'soap', it shouldn't be done on the drought-stressed plant, or in hot weather (over 80F), and most likely not in full sun.

Usually, spraying with water from the hose is recommended, as insecticides have limited effect on whiteflies - they have to have direct contact with them to be killed.

The best control are natural enemies that could be killed with some sprays, and regular spraying off. Sticky traps work well too.