River birch leaf yellowing in Houston area
 

I planted a River (Red) birch a year ago.

It is doing well except for occasional yellowing and dropping of the
inner, smaller leaves. This occurs in cycles in which groups of leaves
yellow and fall, then no more yellow for awile, then the cycle
repeats.

Outer leaf growth is vigorous.

At first I thought it was iron chlorosis, but internet research has
led me to believe that it is birch leaf blight. per
http://msucares.com/newsletters/pest.../19980903.htm.

Some of my tree's yellow leaves had similar brown spots.

Is there any treatment for this or just something to live with?