296 REPORT OF THE BOTANICAL DEPARTMENT OF THE 
Cutting back and cultivation seemed to help them. As pre- 
viously reported, the injury to bearing orchards was confined 
to the bark, mostly at the crown, younger trees sometimes 
being girdled and shedding many leaves during the summer. 
It is advised to remove the dead bark and paint over to prevent 
rot. It is thought that high, exposed hillsides are preferable to 
lowlands for orchards, more injury occurring on the latter. 
Late cultivation and excessive fertilization should be avoided. 
In the Report of 1906 he gives observations on some typical 
apple-tree cankers which were studied in longitudinal and 
cross sections. ‘The cankered areas occurred on the sides 
most injured, and apparently the canker fungus largely got a 
start here through the smaller twigs that had been entirely 
winter killed.” 
A thoughtful discussion of the “ chestnut bark disease” is 
printed in his Report for 1908, in which a number of weighty 
reasons are given to show that Diaporthe (Valsonectria) para- 
sitica is not the primary cause of the chestnut tree disease of 
part of the Atlantic slope, but that winter-injury is responsible. 
Another brief but significant note on Crown-rot was pub- 
lished by O. B. Whipple, in which two types of root rot are 
reported, one showing no preference for varieties and rotting 
only underground parts, the other affecting only the Ben Davis 
and Gano, but injuring both trunk and roots. The second 
type is said to be very destructive; the bark-turns brown and 
the yellowing leaves drop early. The disease is thought ‘to be 
infectious because Ben Davis trees, which were situated so as 
to receive drainage water from affected ones, were also found 
injured. However, the suggestion is made that “ Ben Davis 
and Gano are very tender as regards the application or arseni- 
cal sprays * * * arsenic collecting about the crown of the 
tree and killing the bark.” 
W. T. Macoun!? gives an extended discussion of frost injury, 
stating also that many trees were root-killed and crotch-injured 


Colo. Agri. Expt. Sta. Bul, 118. - 1907, 
12 Canad. Exptl. Farms Ann. Rept. 1908, pp. 110-16. 
