414 



Illinois Natural History Survey Bulletin 



Vol. 23, Art. 4 



ling trees and in some grafted trees brown fig. 11, with no evidence of disease in the 



streaks may extend from the diseased roots of these trees, 

 trunk into the heartwood and occasion- 

 ally into the sapwood of the roots. In Branch Pathology- 

 most of the grafted trees examined, the 



brown discoloration was confined to the Branches that wilt on wetwood-affected 



trunk wood above the region of grafting, trees show, in the current-season wood, 



I 



ri^. 13. — Branch dieback on a wetwood-affected elm on which wilting occurred several 

 years in succession. 



1 



