Grab something to drink or eat, this will probably be a long one, but I want to give all info possible.
I collected a pine in spring of 2019, with a good root ball and planted it in pure pumice, didn’t touch the native soil. It grew ok last year and had a lot of buds this spring, even some buck buds. All seemed great, it had clearly survived the collection and seemed to be headed for a great growing season 2020.
In mid May I noticed the first 2nd year needles started to drop. I wasn’t worried as it had dropped needles quite early the year before as well. And only the weakest two year old needles were shedded. Some had black/dark spots but I thought it was some leftover damage from a scale infestation I had last year. In the past weeks more and more old needles have been falling but the candles have been extending nicely so I thought maybe the tree was balancing needle mass to give room for the new growth. We had an abnormally wet winter so I figured maybe some roots had died and the tree couldn’t support all foliage so it was shedding the oldest.
But the last few days I’ve started seeing last years needles also dropping and that’s when I noticed a distinct yellow/red/brown banding around the dark spots, so now I strongly suspect it’s needle cast.
I directly treated with a home remedy spray of apple vinaigrette, soap and water. I’ll get fungicide on Monday and start treatment. But due to my slow response the fungus has spread quite widely and I’m afraid I might lose almost all foliage apart from this years new growth.
So my questions are:
- Should I try to remove all infected needles, even the ones still firmly attached to the branches (to reduce the amount of spores) or do I let the tree discard the needles and pick them off when they almost fall on their own (to let the tree retrieve everything it can from the needle)?
- If I’m left with only this years needles on the tree, how likely is it for the tree to survive?
- Apart from being careful not to overwater and treat with fungicide, is there anything else I can do to help the tree recover?