WINTER INJURY 257 



ter. This is particularly true if the growth has continued 

 late and has not matured well the previous season.^ It 

 may also be due to an inherent tenderness of the varieties. 

 The result of this injury is much the same as from cutting 

 or shearing back the terminal growth; that is, the uninjured 

 buds nearest the terminal will make a longer growth than 

 if no injuiy had occurred, while the more proximal ones are 

 likely to remain dormant. 



224. Killing of patches or areas of bark on the Umbs and 

 trunk is also a common type of injury. This will first ap- 

 pear as a sunken area which eventually dries and cracks. 

 It is thought that considerable of the black-rot canker 

 (Sphccropsis malorum, Peck) so common on the apple in 

 some sections is due to the entrance of disease spores through 

 openings in the bark caused by the splitting or drying out 

 of the dead areas. This type of injuiy may also take the 

 form of frost-cankers. (Fig. 35). 



Large dead areas on the trunks of the older trees are also 

 conunon in the more northern sections, particularly on Bald- 

 win and King apple trees. This injury is occasioned by much 

 the same set of conditions as produced the dead areas on 

 the smaller branches. It is somewhat more serious, how- 

 ever, for there is opportunity to remove an injured branch 

 but it is difficult to repair damage to the trunk. The bark 

 in this case will loosen and come off. Unlike sun-scald this 

 injuiy does not occur on any particular side of the tree. 



225. Crotch injury is characterized by a kilHng of the 

 tissues in the forks or crotches of both large and small 

 branches. The injury may be restricted to a small area or it 

 may be more extensive. Many varieties of apple may be af- 

 fected, such as Ben Davis, Baldwin, Rhode Island Green- 

 ing, and even Northern Spy. Several theories have been 



^ Emerson, R. A. The relation of early maturity to hardiness in 

 trees. Nebr. Agr. Exp. Sta. 19th Ann. Rept. 1906. p. 101-110. 



