Beginner Gardening: Lemon tree affected by various things - need help with treatment, 2 by macsdev

macsdev wrote:
Hello,

This is my first post. Please forgive any mistakes. I recently moved into a place with a lemon tree. Tree seems to be affected by several things - black spots, curling leaves and some white cotton ball like stuff. Attaching a couple of photos. I went to the neighborhood home depot and they recommended a couple of products to use:
1. [HYPERLINK@www.homedepot.com]
2. [HYPERLINK@www.homedepot.com]

I have been applying these two per recommendation monthly but the tree shows no sign of recovering. I suspect I am not doing the right thing. For one the plant food seems to be aimed at tomatoes. Please advise what to do to revive the lemon tree. thanks in advance.