Pruned Pickering Dropping Leaves

[Carbo]

After the last mangos came off my Pickering I gave it a pruning.  Within two weeks its been flushing like a plant on steroids.  Lots of new growth.  But I'm also seeing many of the older leaves dropping to the ground with what appears to be fungus.  It's been very wet lately here in south FL.  I'm reluctant to spray the tree for fear of damaging the new growth.  Should I spray and if so what should I use?  Or is this a temporary phase?

[Seanny]

Your tree is not getting enough nutrients from roots to feed new growth so it’s pulling them from older leaves.
That’s why the older leaves are turning yellow then dropping.
Normal.

[Carbo]

Interesting if that's the issue.  I gave it two light feedings of 8-3-9.  Once right after pruning and another two weeks later.

[achetadomestica]

How's the new growth look?
If the new growth is good I wouldn't worry.

[Carbo]

The new growth appears to be healthy and vibrant.