I'm going to quote this study from Univ. of Illinois. http://web.extension.illinois.edu/state/newsdetail.cfm?NewsID=5814
Underdeveloped roots could the reduce the ability to recover/survive from diseases or drought. I do apply some nitrogen in the late spring (~first week of may). I normally go with a fast acting one to avoid feeding into the summer. Mid summer I might do half bag rate of Milo.