Sycamore tree losing leaves

[Jim Kresge]

Spring comes in Northern California.  The leaves come out on my big 
sycamore tree in front of the house.  Then, mysteriously, the leaves wilt 
and turn brown (some of them stay green though).  Then some leaves fall 
off.  Later in the June time frame the leaves comes out again and reach 
their full size, then fall off again in the late fall.  I have heard that 
this is because of a elm disease-like fungus.

Can anybody advise what this is and what the treatment is?


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