Preliminary Investigation of Oak Diseases in Illinois

Abstract

IN our investigation of tree diseases in Illinois the cases of disease of oak that have been brought to our attention have increased each year since 1934. These cases have consisted mainly of canker and dieback diseases of small to large branches. Species of Gnomonia, Marssoni, Phyllostica and Septoria, some of the fungi that cause leaf diseases, have been studied by other investigators, and control measures have been recommended. Many heart-rot and a few root-rot fungi, namely, species of Armillaria. Fomes, Hydnum. Polyporus, Stereun and Ozonium, have been studied by others in relation to their parasitism of oaks. Only a few twig-blight and twig- and branch-canker producing fungi, principally Cytospora chrysosperma(Pers.) Fr., Diplodia longispora Cke. & Ell., Nectria cinnabarina Fr., N. galligena Bres., N. ditissima Tul. and Strumella coryneoidea Sacc. & Wint., have been investigated by other workers. The diseases of oak studied by the author and the fungi associated with them are described in this paper.