STATU POMOLOGICAL SOCIETY. 37 



bark sinks, dries out and finally separates from the wood giving 

 much the same injury as in the summer sun scald. With some 

 trees, especially cherries, we have a blistering and cracking of 

 the bark. It is more common west than in New England and 

 more apt to occur on high headed trees with exposed trunks. 

 The remedy is to protect the trunks of susceptible trees by 

 shading. 



Low temperatures, or, rather more frequently, alternately 

 freezing and thawing is responsible for more injuries to fruit 

 trees than high temperature. Late frosts in the spring may pro- 

 duce a blistering of the leaves, and very frequently cause what 

 is called "frost band" of apples and pears. This latter is very 

 frequent in some parts of New England. A late frost catches 

 the young fruit soon after it is set but does not injure it enough 

 to cause it to fall. When the fruit enlarges there is a distinct 

 and often very marked russeted band around it half way between 

 the stem and blossom ends. Bordeaux mixture may also cause 

 a russeting of the fruit but this occurs in blotches and patches, 

 and not in well marked rings. 



Frost cracks are more common on the trunks of certain forest 

 trees than on fruit trees. Very lov/ temperatures, especially if 

 accompanied by a cold, dry wind causes the tissues of the wood 

 to shrink. The wood and bark split in long cracks along the 

 more exposed side. Once opened the crack may split open 

 repeatedly, winter after winter, and yearly attempts to heal may 

 result in a well defined ridge along the trunk, called a frost 

 ridge. 



Frost patches are very characteristic upon winter killed or 

 winter injured trees, more especially on the larger and medium 

 sized limbs. On badly frosted trees the bark on the smaller 

 limbs is apt to be pretty generally killed. These frost patches 

 on the larger limbs can be seen early in the season following the 

 injury and are prominent all summer. There is a sharp line on 

 the surface of the bark marking the junction of the dead and the 

 living tissues. As the dead bark dries out the tissues contract 

 and stick to the wood below. The bark very frequently is of a 

 lighter color and may crack away ^lightly from the healthy por- 

 tion. The patches are of various sizes but are generally elon- 

 gated in shape. If the tree is not entirely killed, healing of the 

 wound is started but instead of forming a callus with a thick 



