Garden Pests and Diseases: Brown patches on my Banana Shrub?, 0 by astcgirl

astcgirl wrote:
I have about 5 Banana Shrubs (Michelia figo) not all from the same place. One is even the Improved Banana Shrub (Michelia skinneriana) .

I have got weird looking brown patches on the leaves. It is only on the backside of the leaf, usually starting at the stem and then splotching in other places. The new leaves are unaffected, so I am thinking it is some type of mold or fungus that spreads other than a virus. It ends up turning the leaf yellow and dropping. All of my banana shrubs have it even though they are in different parts of my yard. I have not noticed it on any other plants. It doesn't effect the flowers, they still bloom and smell wonderful but I'd like to get rid of it.

THey are all in pots. I have tried spraying with neem but to no avail.

I dont' think it is an insect as I can't scratch the brown off, it doesn't wipe off (I tried with alcohol) it is as if it's embedded in the first layer of the leaf.

Any ideas of 1) what it is and 2) how to get rid of it?

Should I trim off all the leaves?

Thank you for any help