Crab apple tree was sprayed for apple scab but at the top the leaves are turning brown. There next to open field so maybe wind and sun are playing a role. I though maybe rust. From the picture what would you guess?
The pictures are a little fuzzy so my first question is are you sure its a crabapple? The foliage almost looks like common buckthorn. If you never see flowers in the spring, yet fruit in late summer its a buckthorn. Please respond and we'll go from there.
can't remember Im thinking it gets a reddish flower in early may
Well then it is not buckthorn. It may be a little chlorosis, we are seeing a lot of that with the wet weather we had this year. Most likely the tree will recover just fine next year.