Question
I live in California where when I checked online, stated that I was in zone 9. I don't know if that is of much help. I have had this lemon tree for quite some time now where it used to supply us with an abundance of lemons. Quite recently, I started putting more effort into caring for it. I watered it daily instead of when it was convenient for me, I also invested in some citrus fertilizer and researched a lot about the lemon tree. This move made a big return in that the tree had its own growth spurt, beautiful green leaves and something I would consider a large amount of fruit yield. However, along with the joy of seeing my lemon tree grow, I noticed the ants that were ALL OVER the branches. I then noticed that they were going to small fruits that had some white sticky looking residue. After researching for some time, I realized that these white residue were actually scale. I am not sure if this was a good move but I sprayed the tree with white oil and trimmed the tree of branches that were infested with these scale. Now, I am hoping that these scales don't come back.

If you think that's the end of the story, well besides wanting to know of what I should do about the scale problem, I also have a problem with the branches that have these scab looking brown spots. I noticed them and thought it was sign that the tree was aging or something. But I doubt it. I wipe the branch and on my finger are many brown dots. I'm not sure if these things are alive but I've tried squeezing them and they sure don't have guts coming out of them. They worry me though. Should I just get rid of the entire lemon tree? I have other citrus tree next to it and an avocado tree on the direct right of it. I am caring for all trees and would be willing (though reluctantly) to get rid of the lemon tree if it means keeping my other trees safe and disease-free.

Answer
I would not get rid of the lemon tree.  The oil is about all that you have to treat for scale on edible fruited trees.  They can come back, however, so keep a close watch.  If the brown scabby spots are on the old original growth of the tree before you treated with the oil, they may be lenticels that have incresed in number.  Lenticels are naturally ocurring breathing holes in the woody parts of plant tissue.  When you sprayed with the oil it covered and coated these breathing holes, and the plant may have responded with making more than it really needs.  I assume your tree is in the ground and can not be moved, so you cant help it if the sun shines on it after the oil treatment.  This would cause the tree to do funny things, because you coated the entire surface of the tree as well as the bugs.  I wouldnt do anything right now but watch it closely for any changes.  Let me know if something does change dramatically. Good Luck.