I purchased (2) 8 foot aspen trees from a nursery in the area in late summer of 2024.  I planted both with proper protocol.  One is fine and continued healthy growth through the fall.  The other's leaves became leathery and curled inward, although kept it's leaves until normal fall leaf drop.  I called the nursery who said it was a fungus and that I should apply a fungicide to the buds in spring.  

Can you recommend a specific fungicide?  I see that there are different kinds - copper, 3 way, systemic..etc.  I am hesitant to request this information from the nursery and would like to have the product on hand to be at the ready at bud break.  If you have any other information to impart, I will appreciate your response.

Thank you!