Browning on Jade

I have noticed an increasing number of brown 'spots' on one of my jades. This partcular jade (I don't know the variety) is shaped like a trumpet. Most of the spots on the inside of the concave area of the tip of the 'trumpet'. Is this something I should be concerned about? And if so, what should I do? The plant seems healthy otherwise. Here's a picture.

Could be mites or thrips. Do you have a good hand lens? Take a look.

Jade trees get a powdery mildew, but I've never seen it. I have seen powdery mildew on Sedum, however, and it causes a strange scabbing much like that. Again, with the hand lens, you might be able to see tiny transparent chains of spores coming out of the spot.

But really, I have no better ideas, and those aren't very good. Excellent picture, however.

Thanks Nina, I have checked with a hand lens and didn't see anything 'crawling around'. I'll check again for spores. I was rather pleased with the picture too