Leaf spots on Malus Tschonoskii

I just purchased a Malus Tsconoskii but within a couple of days yellow/orange spots started appearing on the leaves and within a week every leaf was affected. 

Garden centre tells me it is fungal, should only affect the tree this year and won't infect other surrounding trees

Can anyone confirm this because I have a lovely old apple tree and another young crab which I don't want affecting

Thank you

Last edited: 26 May 2016 12:52:46