What is causing this to happen to my tree?

[DBV]

My orange tree used to produce large, orange fruit. Now, the oranges are much smaller and have a brown discoloration. What might be causing this to happen and can it be cured?

 

[Sheshovel]

Would you give me a close up of a few of the leaves closest to the fruit and also a close up of the fruit itself off the tree,so I can see the brown areas better?
Also a shot of the base of the tree and area around that.
Are you using any chemicals on this tree?
This can be many things.I need those shots to better determine what the problem is.
There is also A good book by L.C.Knorr "Citrus Diseases and Disorders" you might try and find.

 

[DBV]

I'll post the pics you need tomorrow morning when it's light. I haven't used any chemicals on the tree ever.

 

[DBV]

Here are some pics of two oranges I pulled this morning and the leaves next to them:

This morning was the first time I had noticed the white substance under any of the leaves. I have no clue what that may be.

 

[DBV]

And pics of the base of the tree:

I had forgotten to mention the white speckles that dot the entire tree. They don't move so I figured they weren't bugs. But could they be eggs? Someone had mentioned to me to look for rust mites but I haven't seen any yet. I honestly don't know what one looks like.

 

[Sheshovel]

I am sorry but I believe you have a combination of a pest and fungal problem with this tree.I suggest you post these pics to U.C.Davis agricultural dept,
and see if you can get a plant Pathologist to help you.I have an idea of what the problems are but I won't say for fear of misdiagnosis in this case.I will save your pics and see if I can find more info than what is available to me on this now and get right back to you.

 

[LightningLoader]

oil spray for everything

Rust mites on the fruit. Use Agri-mek or oil spray. Foot rot on the trunk (phytopthra)? If so use Ridimil gold.

 

[LightningLoader]

http://edis.ifas.ufl.edu/CG009
this is a link on the foot rot

 

[LightningLoader]

Here's a great link for you to keep on file as a home citrus grower. Has pictures of common problems and suggestions.
http://edis.ifas.ufl.edu/HS141