New York AGRICULTURAL EXPERIMENT STATION. 303 
year-old trees are said to die in various states of the Middle 
West as a result of the parasitism of this fungus, especially 
in orchards on recently cleared land. Trees with injured root 
systems become evident by their over-production of fruit. 
The fungus was transferred from oak roots to apple roots 
and is said to have proved deadly within the year. Further 
studies were promised but seem not to have appeared. At 
any rate, in Bulletin 149 of the Bureau of Plant Industry on 
‘“ Diseases of deciduous forest trees,” by von Schrenk and 
Spaulding, only brief mention is made of this fungus as caus- 
ing the death of oaks and getting on fruit trees in newly 
cleared land. 
FUNGI ON TRUNKS AND BRANCHES. 
Perhaps the best-known example of the fungi commonly 
found on dead bark or cankers of trunks and branches of apple 
trees in this region was described by W. Paddock.** This 
Spheropsis canker was found doing very much damage, es- 
pecially on Esopus Spitzenburg, Twenty Ounce, Baldwin, 
Wagener, Greening and King, while Tolman Sweet was found 
resistant. 
The affected trees are characterized by rough, enlarged re- 
gions on the larger branches and areas of dead bark on the 
trunks. Spheeropsis pycnidia appeared on most cankers, while 
on others the fungus is said to have died. Sometimes a branch 
having wilting or dying leaves is found to have a girdle of 
dead bark which is said to “ cut off the flow of sap.” However, 
it was shown by Paddock that Spheropsis mycelium pene- 
trates the wood but seldom. 
Spheropsis is said to infect trees in spring, becoming evi- 
dent as. areas of discolored bark which seem to spread till 
mid-summer and then produce pycnidia. Infection is supposed 
to occur at wounds and injuries of various kinds on trunks 
and branches. It was shown by numerous experiments that 
the fungus could produce cankers when introduced under liv- 
ing bark, but that it seems unable to do so when placed just 
— 
2 The New York apple-tree canker. N. Y. Agrl. Expt. Sta. Buls. 163 
(1899) and 185 (1900). 


