APPLE DISEASES 
Fig. 1. Winter Injury to Young Apple Tree. 
formed. There is great danger of sep- 
aration of the bark layer from the wood 
at that time as at others. The sun ex- 
posed side seems to suffer worse by rea- 
son of the more extreme temperature 
changes which were incited on these ex- 
posures. It is evident that warm periods 
in winter are a source of danger when 
followed by low temperatures. 
Upon very large trunks near the base, 
as on Grimes and some others, this may 
be the real explanation of frequent sun 
scald or basal injuries. Wherever such 
an injury begins there is risk of the in- 
trusion of wound fungi with all the con- 
sequences which follow their entrance. 
The handling of winter injuries must, so 
far as prevention goes, precede the condi- 
tions which cause it. Where possible the 
497 
prevention of excessive late growth is de- 
Sirable. In cases of orchard trees it may 
be that mulches of coarse litter, espe- 
cially, will prove serviceable. It may be 
added that this injury to woody growths 
is a less developed phase of the killing 
back of herbaceous plants by the prema- 
ture frosts. 
Another phase still is the killing back 
of branches at the tips of woody growth 
which are not strictly hardy in our cli- 
mate. In the case of our Japanese plum 
and of some ornamental shrubs, this is a 
frequent phenomenon and its cause is to 
be sought in the same factors above de- 
scribed. Growth being protracted late in 
the season, these water-gorged terminal 
twigs are killed by the subsequent winter 
freezing whenever this is severe. 
See Sun Scald. 
A. D. SELBY 
Winter Injury and Cankers 
Ben Davis and Gano apple trees died 
in such large numbers throughout Iowa 
during 1912 season that the Iowa Agri- 
cultural Experiment Station Horticultur- 
ists, S. A. Beach and Lauren made a 
thorough investigation of the districts 
most affected. In their preliminary re- 
port they say that injury and death of 
these fruit trees is due to a number of 
factors, chief of which are cankers and 
blight caused by various parasitic dis- 
eases; the early fall freeze of October, 
1909; the late spring freeze of April, 
1910; the dry season of the summer of 
1910, followed by the cold winter with 
comparatively light snow, and the ex- 
treme drouth and heavy crop production 
of 1911. 
All of these factors tended to weaken 
the vitality of the apple trees, and par- 
ticularly of the older and less vigorous 
ones, rendering them less able to with- 
stand the unusual and continued low 
temperatures of last winter. Those or- 
chards which had been well cared for are 
showing less injury than neglected or- 
chards and their trees are recovering 
more rapidly. Also, the younger and 
more vigorous trees recovered more rapid- 
ly; they were also less injured. 
In general, those trees which were 
