Issue with Navel Orange tree

I am having an issue with my navel orange tree. There is a white looking substance starting at the base of the trunk and going up the branches. It is not "scale" that you can rub off. In fact, it is almost embedded with the tree. There is no "scale" on the leaves. I have included a photo. Can anyone tell me what I should use to get rid of this problem? Thank you very much.

 

The lack of detail in the picture makes it difficult to compare but at a distance the substance resembles that seen in the thread Citrus tree in DIRE NEED OF HELP | UBC Botanical Garden Forums and the thread Is this the dreaded Mealy??? | UBC Botanical Garden Forums.

 

Thanks for the information. I think it might be more like those other posts. I will also get more detailed pictures and post one of those.

Thanks for your help!!

 

Do you have any suggestions for what to treat the scale with? Thanks, Neal

 

I would first positively identify the type of scale then follow the suggested treatment. Generally speaking though, I believe horticultural oil would be effective in an outdoor environment.

 

Unfortunately, horticultural oil will not control citrus snow scale. You will have to use a insectcide, or scaleicide. Check the Internet under Snow Scale Control for recommendations. - Millet (1,433-)