Question
Hi Edward, I just asked this at another area ("Trees") and I believe the question went to someone else.  I had searched for "paulownia" here and it found nothing!  Yet I managed to find this page http://en.allexperts.com/q/Shrubs-735/Royal-Empress-Tree-questions.htm so apparently the search isn't working.  Could you please read this and tell me what you think?  Thanks.

Hello, I recently got some Royal Paulownia saplings via a
place online.  One was DIT, the other two I planted in pots
temporarily until they were large enough to go in the yard.

A few weeks after planting, I noticed brown spots appearing
on the BOTTOM leaves.  Within about 3 days, the spots are
all over the affected leaf which has turned yellowish, and
then it falls off.  For some reason the affected leaves are
always on the bottom of the plant.

Sounds to me like either Phyllosticta paulowniae, Sphaceloma
paulowniae, or Anthracnose?  Please see these images I took
and see what you think, (I made them of varying brightness
due to monitor differences):
http://www.orpheuscomputing.com/images5/PaulowniaLeaf1.jpg
http://www.orpheuscomputing.com/images5/PaulowniaLeaf2.jpg
http://www.orpheuscomputing.com/images5/PaulowniaLeaf3.jpg
http://www.orpheuscomputing.com/images5/PaulowniaLeaf4.jpg
http://www.orpheuscomputing.com/images5/PaulowniaLeaves.jpg
The last one of course is after some leaves had fallen off.

I was keeping them outdoors in the sun, but at first I
thought this may be due to heat so I put them in the shade
(which of course didn't help).  I water them when the dirt
gets dry.  They were planted in decent potting soil bought
at a nursery.  Since their planting, it's been about 88-95?
here during the day, and 70-78?at night, and always high
humidity.

I'd really appreciate if you could give me your opinion on
what this is, and any course of treatment if any.
Thank you,
-Clint
Baton Rouge, LA

Answer
Clint,

First, I couldn't access the pictures that you attached, but I will venture a guess anyway. There has been occurences of leaf spot attacking the leaves. I would recommend using a broad spectrum fungicide on the trees to minimize the damage now. You will need to treat them early next spring (as the leaves are emerging) to get better control.

Good luck,
Ed Gulliksen