448 DISEASES OF ECONOMIC PLANTS 



upon the stems also turn black and die. Infection pro- 

 ceeds to the supporting twigs and may result in dead 

 patches of bark upon quite large shoots. 



Cutting and burning infected twigs is advised. 



SASSAFRAS 



Heart rot (Fomes Ribis (Schum.) Fr.). — Spaulding 

 in 1907 ^ described this rot as a serious injury to sassafras 

 in Missouri. It is also found upon stems and roots of 

 various shrubby plants, as rose, currant. By means of a 

 wound the attack is made upon exposed heartwood, 

 proceeding slowly into the sap wood. The sassafras is 

 thus immune until it reaches an age bearing heartwood. 

 The decaying wood is abnormally light in color and 

 slightly reddish, and the affected region is bounded by 

 a narrow black zone. Trees sometimes die from the 

 attack. 



The causal fungus has been reported in America from 

 Kansas, Missouri, New York, and New Jersey. 



SYCAMORE 



Gnomoniose {Glceosporium nervisequum (Fckl.) Sacc. of 

 Gnomonia veneta (Sacc. & Speg.) Kleb.). — First noted in 

 1848, this anthracnose is very widely distributed from New 

 Jersey to California and Mississippi. In extreme cases 

 it may so weaken the trees as to cause their death. The 

 scorched appearance of the leaves and defoliation render 

 the trees unsightly. Just before they become full-grown 

 the leaves give the first indication of the attack. Begin- 

 ning near the veins or ribs or upon the petiole, the disease 



' Spaulding, Perley, Sei. n. s. 26, 479. 



