Hi all I joined this forum in the hope that someone who knows about indoor grown avocado trees might be able to identify these strange black dots in the attached photo (you may need to zoom in to see them). Please ignore the burn marks on the leaf, as that was due to an unfortunate over-fertilizer incident when I left it with someone for the summer... I've grown this avocado tree from a seed and it's about 2 years old now, and is growing happily, however over the last few months these little black dots seem to appear along the veins, followed by discoloration/flaking of the green part of the leaf. I've tried changing the soil and repotting it, also cleaning the leaves with soapy water. The plant is still growing and not really showing any other side effects. Also these dots appear over very slow periods of time, so I've been thoroughly checking each leaf every week or so. Finally, I can scratch them off with my nail when I spot them. Any help would be greatly appreciated! I've been cutting off leaves when the 'rash' (for lack of a better word) gets too excessive, but I can't keep doing this forever or I will have no plant left at the end of it!