APPLE DISEASES 35 
Frost-Insury 
Caused by the action of low temperatures 
The remarks which follow apply for the most part to that 
phase of frost-injury commonly known as winter-injury. Prop- 
erly winter-injury includes injury to all parts of the tree caused 
by low temperatures in the winter months. Some attention 
will be given to injuries due to spring frosts, but the general 
statements are made with a view to an explanation of the 
important problem of winter-injury. Of all the phases of 
frost-injury, sun-scald and crown-rot, or collar-rot, are most 
prominent and will therefore receive proportionate attention. 
Sun-scald is now regarded as a late form of winter-injury, 
while crown-rot is an early form of winter-injury. The term 
frost-injury is used broadly to include all injuries to fruit-trees 
due to the action of low temperatures without regard to the 
season of the year. ; 
For many years it has been commonly observed that most 
fruit-trees suffer from the effects of severe cold and of sudden 
and extreme temperature changes in the cooler seasons. 
Authenticated records date back for a century and unquestion- 
_ ably the trouble was as common then as it is now. Theories 
were advanced immediately in earlier times to explain the 
occurrence and action of frost, some of which are still promi- 
nent, although each has been modified in some degree. All 
kinds of fruits are injured at some time or other ; however, there 
is noticeable difference among fruits in this respect. It is 
generally accepted, for example, that while the apple is severely 
injured by cold, the peach is the more susceptible. 
In the northeastern United States such apple-varieties as 
the Ben Davis, Northern Spy, Baldwin, Rhode Island and 
Tompkins King are all likely to suffer from cold. Others, such 
as the Oldenburg, Grimes and Hubbardston, often exhibit 
