I searched in Internet a lot, but still couldn't find what is wrong with my lemon tree.
What cause could be for this type of leaf defects? Some leaves on some branches start to dry out from side.
The funny thing is that in 2012 summer leaves became yellow. So I started to fertilize it. Leave green color returned and as surprise on October 2012 tree thrived new leaves. So I continued to fertilize slightly. Next surprise was that now on January 2013 tree thrives new leaves again. But some of those from October dry out from sides. Also 1/2 of leaves slightly curve down.
No obvious insects. Fungus? Overfertilizing?