Tangerine Tree in pest/disease danger. What do I do?

I hadn't seen my parent's tangerine tree in around 2 weeks, but when I did I found this. As you can see from the photos the leaves are drying, curling, turning brown, and falling off. I've been checking online, but I don't know if it's suffering from multiple problems or a single problem. Can anyone identify what is wrong with the tangerine tree? What should I do?

EDIT: I've added video. The video also includes white silk like material and black marks under the leaves.

It does look like a fungi is attacking your tree. Have you contacted your local state extensions office or 4-H? I know it would be preferable to get the answer here but some of those folks actually know what they're talking about.

Have you tried fire?

Thank you. I was able to find a list at http://ceriverside.ucanr.edu/About_CE_Riverside/contact/ and have sent out an email with my issue.

listen to Can. Its a better band

Wow, that made me go out and check my one tangerine. It has had, as well as the lemons, a bit of leaf curl over the years. Usually on new growth. But nothing as bad and dry as what you have. My orange, which is an old navel, looks nearly unblemished.

You are right in taking the course @kidblue has suggested. Have you had a freeze in your area? My miserable Mexican Lime developed curled and dry leaves, and some whole branches died from a freeze. Too tough to do me a favor and totally croak, though. Excellent screening tree for along the fence, why I keep it..

I'd also water if rain or irrigation hasn't happened for a long time, and maybe even spread some citrus fertilizer pellets around the base. Also, you could ask the local nurseries, or perhaps where you live has an arborist or city division/service. Or agriculture.

I live in Southern California so it hasn't dropped below 55 degrees. My parents have around 9 citrus trees and I've also found that some of them have leaf miners. The leaves look exactly as described in this video I found on youtube.

They have been watering the trees, but maybe the citrus fertilizer pellets would help.

Mold/Mite plus nitrogen difficant.no expert by any means. Ladybugs may be introduced if it is a mite problem should clean it up with time.

I second @berserk007 in the ladybug suggestion if there is indeed a mite problem; Ladybugs, used correctly, are amazing at getting rid of soft-body insect pests. I don't necessarily think that's all that's going on here, though. I'm on the east coast and have no experience with citrus trees, but I highly recommend you try posting this on reddit; there are some really knowledgeable people on the gardening and botany subreddits, for example, and there might be more specific ones for your particular problem.

Edit: Also it really can't hurt to give it a spritz of diluted hydrogen peroxide for the possibility of fungal contamination. If you're worried about the chemicals, cinnamon or really, really strong chamomile is a surprisingly strong alternative.

I don't have a reddit account. Is there a trial period to be able to make topics?

This is how Interstellar began, right? Looking forward to eating nothing but corn.