My two Meyers lemon trees have been doing poorly the last couple of months. In particular they seem to be loosing leaves at a rapid rate, and now the worse of the two has lost maybe 80-90% of its leaves. I knew that the trees were due for a transplant (and one started not flowing water quickly through the pot recently), and I had a bit of trouble with spider mites and aphids (although I think that is largely under control now). However the leaf loss continues, despite the transplant and regular spraying with oil spray.
I am thinking that it may be more than one (or two) issues here, so I thought I should describe the problem and post pics to see if anyone can point me to other problem(s) that need attention.
These trees (and some other citrus that are doing fine) were stressed last Sept, as they were out on a porch when we were evacuated due to a wild file. They went without water for 10 or so very hot days. They were water well when we returned, and all, including the meyers seemed to recover from that. Leaf growth and coverage a few months ago was pretty good. The trees lost a bit when they came in for the winter but then stabilized until a couple months ago when the leaf loss accelerated. The pattern is that a leaf will turn blotchy yellow with islands of green (almost spots of green), and then fall off. Often just the leaf, not the petiole. This effects new and older leaves.
I've attached two pics, one of two leaves still on the tree, with these characteristic yellow with green spots. You can see some of the now bare branches in the back of this photo. The second of a typical leaf that came off the tree. Note some dark/dirty areas on this leaf.
I've been spraying with Volick oil and a soap spray (alternately), and it seems to be working no more aphids, a few mites that I see, and no white flies (Although the recommended spray period is a bit too long in that I see signs of more bugs before that period is up, so I have started spraying more frequently). Not sure if there are other bugs working here, I do see one or two (literally) holes in the leaves, but it did not seem to be enough to worry about.
When I transplanted the worse of the two meyers, I did not see any signs of insects in the soaking vat, which it sat in to loosen the old potting material.
The roots seemed healthy when I transplanted the one tree, although quite crowded. (this just happened, so too soon to see of the xplant will fix things).
So my question is, what is going on here. Is there some bug or disease that is effecting the trees? What could cause this leaf yellowing with green spots remaining? Possible watering issues?
Suggestions?
