Troubled lime tree in southern California
I have a lovely lime tree growing in the ground out on my back patio. In other words, there's an opening in the patio where the tree grows. The tree is about 10' tall and has been delivering a never ending crop of beautiful, juicy large limes since I moved here in July 2010. I love the tree. I noticed last year that the tree had a few yellow leaves and a constant parade of ants crawing up into the heights. I watched the ant trail carefully and saw them feeding on what I believe to be white, fibery spider mite patches. This summer, I have also noticed leaves with patches of tiny black spots on the backside that appear to be itsy little insects of some kind, resembling tiny poppy seeds. Long story short, the tree's leaves are yellowing and falling in droves. The bottom branches are almost leafless and the limes this summer look like a pack of hobos who've been at war. I want to help this beautiful little tree but don't know how. Having moved to California from New York City recently, you can imagine that my experience with citrus trees is at best, non-existant. But I want to help it because I just love it. I water it every weekend. There is a very healthy lime tree peeking over the fence behind me, so I don't know why my little guy is so infested and that one isn't. I've also struggled with my little orange tree that is pot planted nearby as well. Some creature who leaves slime behind just pops off the baby oranges and eats them like popcorn. Who could've known these citrus murderers would move in at the same time as I did to kill my beloved limes? Anyway, I would appreciate any advice you can offer. I notice my little lime buddy has some new blossoms up top, so he's trying to make it work. Thanks so much for your time and effort on my behalf.
Try neem oil on your plants. It is effective against many types of insect pests but perfectly safe for you, your pets, and beneficial insects. It is also an effective fungicide. Here is more information: https://www.gardeningknowhow.com/problems/pests/neem-oil-uses.htm