There are two problems here.
One: This tree sat inside all winter. I had problems for a while with little black somethings appearing on the leaves, which then turned yellow and fell off. I sprayed it with safer soap and that finally stopped. Last week it got warm enough and I moved it outside. The little black somethings have reappeared. I have sprayed over and over and they are still there. I brush them off one day and two days later just as bad. I don't know what they are or what to do. It seems plain that they are some bug or other outside organism, but that may be wrong.
Two: My care guidelines said temperatures should be above 55F, and they were, lows 65, highs 85. A couple of nights ago the temperatures dropped to 49F, which should not have been bad, but now several of the leaves have this brown area in the middle. Will that go away?
Care guidelines say not to overwater, and I have been careful about that. I stick my finger in the dirt and if it feels moist, I don't water, even here where everything else dries out in a day.
\Is there a fertilizer problem here? I have never felt like fertilizing a sick plant, but at the moment I will take any advice. (Not only say thank you, I will also do it.)