Brown spots on red sunset maple

Can someone please identify the problem with red sunset maple leafs in the link below?









thx

 

nigth insect ,and little strees for planting ....

 

Not sure what the cause of the brown spots is, but it doesn't look very serious.

BTW, that's a Sugar Maple you have there, not a 'Red Sunset' (a cultivar of Red Maple).

 

the garden centre said it a red sunset maple, and the sun has got to it even more now as the leafs have turned completely brown