Last year I took in a branch from my crab apple tree, extension diagnosed apple scab but it was too late to treat the tree. So, I am wondering if I should treat with a fungicide this year or wait to see what happens. The tree is quite young, about 5 years old, so it is not yet very thick. I did try to keep the leaves cleared. Please advise. Thanks.

HI Nancy, It all depends. If you happen to know the name of the crabapple you can find out if it is resistant to apple scab. in which case I wouldnt advise spraying. Last year was a bad year for apple scab and even resistant ones got it to some extent. Here is an article I wrote that outlines options beyond that. http://web.extension.uiuc.edu/champaign/homeowners/080410.html hopefully this will help you to decide. Sandy