Tangerine Tree Yellow Falling Leaves
Hi, I am desperate for some help/advice to save an orange tree than has been in my yard for a long time, maybe 50 years or more. We bought the house 3 years ago and it always gave off tons of oranges (I think they are tangerines, I'm not quite sure). But this past year, no oranges, and the tree's leaves are yellowing and falling. Someone told me I had been attacked by aphids, so I sprayed the leaves with a water/dish detergent solution (I'm afraid of chemicals due to young baby and pregnant wife). I also fertilized it. This didn't seem to stop the yellow leaves, and I have trouble telling if it helped much with the aphid problem - I've never been able to identify them very well. The tree also has a green looking mold or fungus on it, which you can see in the pictures. The tree is usually watered by a sprinkler system, but this winter I've done that manually to conserve water. I live in California near Santa Monica, so typically it doesn't get too cold.
I posted a few pictures and would love some advice on how to diagnose my problem/s and come up with a solution to save this tree. I'm afraid we might lose it.
Here are pictures:
Here is a link that might be useful: Tangerine Pictures