This ladybug sat still very nicely. I liked that a little crepe myrtle flower was on the same leaf. What I didn't like is that the leaves look a bit black. It might be a mold.
Years ago a lemon tree in our front yard had a similar problem. I cannot remember with what, but I sprayed the leaves. The tree did kind of survive the hard freeze in Texas - it is now a lemon plant, but looks totally healthy!