CHAPTER XI 

 WINTER INJURY 



For convenience, the kinds of winter injury to fruit-trees 

 may be grouped into three general classes: (1) bud injury, 

 (2) injury of the woody parts above ground, and (3) root 

 injury. 



221. Bud injury. — While many factors are involved in 

 winter-killing of plants or their parts, the conditions under 

 which the buds are killed may be roughly placed in the three 

 following categories: (1) when buds go into the winter in 

 an innnature condition and low temperatures occur early 

 in the winter (December); (2) when mature buds are sub- 

 jected to such low temperatures during the winter that 

 their tissues are killed; and (3) when unseasonably warm 

 weather in winter or early spring is followed by very low 

 temperature. 



Of the tissues of the fruit-buds the pistils and ovaries are 

 the most tender and are frequently killed when the other 

 parts remain unhurt. Such blossoms may expand, espe- 

 cially' if the injury occurs just prior to blossoming time, but 

 of course they can produce no fruit. ^ If the entire bud is 

 killed, the tissues throughout turn brown and the bud dries 

 and falls from the tree in the spring in the case of most of 

 the stone-fruits, or it may persist for a time with the 

 apple and pear as shown in Plate VIII a. 



Not all varieties of fruit that are tender in the bud are also 

 tender in wood, as may be illustrated by the Elberta peach, 

 but generally this is true. 



Winter-killing of the fniit-buds of the apple is rare, but 

 1 Bailey, L. H. Principles of Fruit-Growing. 20th Ed. p. 306. 

 254 



