

} 



DISEASE OF BLACK OAKS. 



Ill 



Q 



marilandica and Q 



In all cases 



whore the scientific name is given so that there can be no 

 mistake as to the identity of the host, the fungus is seen to 

 occur only on members of the " black oak " group. The 

 rano-e of the different host species has been ascertained 

 and covers the region east aud south of the curved black 

 line in figure, including the eastern portion of the United 

 States. The localities from which the fungus is known 

 are indicated by stippling. In this way one may see what 

 is the probable distribution of the fungus and in what 

 localities it is likely to be found in the future. 



As far as there is any mention made, the inference is 

 that Polyporus obtusus is a saprophyte only, and there is 

 not the slightest hint of its occurring as a wound parasite. 



trees of Qaercus marilandica and Quercus velulina 

 have been found by the writer in two quite widely separated 

 localities with this fungus occurring as a wound parasite. 



It not only grows on the trees but it sooner or later causes 

 the death of the affected trees. 



On investigation it was found that the sporophores were 

 growing out of the entrances of burrows made by some 

 wood-boring insect. The insect itself has not been seen 



fly 



p 



robiniae Peck. 



mentioned 



a- from 



of the oaks- It works on living trees and burrows in heart 

 and sap wood alike- The 



mo 



years in reaching maturity. 



3d oak is attacked in Maine. 

 Houston, Texas, and it is 



said to attack willow in some sections. It is known from 

 California and probably occurs wherever black, red, and 

 white oak and locust trees grow in this country. Fitchf 



* Packard, Report U. S. Entomological Commission. 5 : 53-58. (1890). 

 t Fitch, Report on the noxious, beneficial and other insects of the 

 State of New York. 5 : 4. (1859). 



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