My datura ( double purple) looks poorly and has black something on the stems. I have sprayed it with Seven spray but I don't know if it is bugs or disease. Can anyone help, please? cillay (Alda)

If you can post a picture of the damaged sections, that would be helpful. I would hold off applying poisons until the problem is identified.

Or try the most non-toxic solutions first, so as not to cause more harm than good. If it is a fungal infection, a good spray with very dilute hydrogen peroxide will often knock it back. If it is bugs, a spray with a solution of dish soap works well, 1/2tsp. dish soap to a quart of water, cover all surfaces, then rinse it off with the hose.

Sometimes just a brisk rinse with a gentle spray of water from the hose does the trick.

But, as Deb says, the best thing is to first identify what you are dealing with. A magnifying glass is a necessary tool in the garden. You can take pictures through it, too, then post them for all of us to see.