Check for spider mites.

That's what angel trumpet leaves do, fall off...lol...if they're not falling off then the thing must have died. It might be rootbound, the light might have changed, it might have been too dry, the temps can cause it, drafts when the plant is inside, spider mites, whiteflies.
If it's not buggy, change it into a new pot and fertilize it after about two weeks.

It's common for the older foliage to drop. Are you feeding it with every watering? I feed my brugs once or twice a week during the growing season but not daily. I also use epsom salts once a month. My large brugs are in 25 gallon containers. Is your brug droopy when you water it? If not you might be giving it too much water which can cause the foliage to yellow.
Karyn

Hi;
I would like to thank everyone for your help. I don't know how I over looked mites. That seems to be what it was after buyorse11888 mentioned it, I took a better look. I sprayed the plant 24 hours ago and it already looks better.
Restless

What do we spray the anger trumpets with for spidermites Barb

Thanks for the information. I am a newbie. 100 species that is awesome. I have a baby datura cream and sugar that is my prized plant for the year.

I have two species of angels growing that I started from cuttings this winter. My neighbor lady said to use murphys oil soap and water.... Barb

Alcohol n water. Kills on contact

What is the proportion of either the alcohol to water or oil soap to water?

I would also like to know what part alcohol to water and Murphy oil soap to water you use on angel trumpets. Maxie

I have two angel trumpets one is fine but not flowering yet the other although flowering it's leaves have small holes in them and are going yellow I presume due to mites, one member suggested alcohol in water may I ask as I am from the UK what type of alcohol is this? and how many parts alcohol to water?
Thank you for any help

Small holes in the leaves suggests snails and slugs - place some slug bait around the soil and that should take care of them until it rains.

I put my slug bait in a clear plastic glass, laid on its side, to keep it from getting rained on. You don't need much - maybe a tablespoon.

You can also put the bait in a beer bottle to keep it dry.

Ive had my brugs for 3 years and just movedto Florida. It’s blooming and appears otherwise healthy but has many yellow leaves and leaves have holes as well. Ive sprayed it with NEEM and Forbid. It has not helped.