HORTICULTURE 91 



in the case of grapes, it is generally done in early spring before the 

 growth starts in the tree. 



Pinching or disbudding is a modified form of pruning and re- 

 lates to the removal of buds. By removing the terminal Dud of a 

 branch the development of lateral buds and shoots is encouraged. 

 Pinching is most commonly practiced with raspberries. (U. S. E. 

 S. B. 178.) 



ORCHARD PROTECTION. 



Throughout the whole life of fruit plants there is danger of 

 injury from a variety of causes. Among the more common of these 

 may be mentioned sunscald; winterkilling of the twigs and roots; 

 winterkilling of the fruit buds; sleet storms; injuries from birds and 

 live stock, from wind, rain, and frost in the growing season ; girdling 

 by mice and rabbits; and injury from label wires, insects, and 

 diseases. 



Sunscald. This is the name given to a condition of the bark of 

 trees which is probably the result of exposure to the sun under pe- 

 culiar conditions. Its effect is usually to injure the bark on the 

 south and southwest sides of the tree which later peels off, leaving 

 the wood exposed. This soon begins to decay and permanent injury 

 results. It has been found that shading the trunk will prevent this 

 injury, hence a common remedy is to cover the trunk with burlap, 

 cornstalks, or similar material, especially during the time when not 

 protected by leaves. The growing of branches on the south side of 

 the tree so as to shade the trunk from the sun and the inclining of 

 the trees toward the southwest are also effective remedies. 



This injury is most liable to occur during severe droughts and 

 in the early spring or late winter before growth has fairly begun. It 

 is supposed to be caused by the warm sun of the middle of the day 

 starting active life in the portion of the trunk exposed to its direct 

 rays. Later, when a cold spell comes, the soluble compounds formed 

 by the renewal of active life are decomposed and the protoplasm is 

 destroyed. The trees most liable to this injury are those that are 

 newly set and weak ; such as have smooth bark, as hard maple and 

 basswood ; also trees with trunks inclining to the northeast and those 

 on dry land. 



It is well known that one portion of a dormant plant may start 

 into growth independently of the condition of the rest of the plant. 

 Thus a branch from a grapevine or other plant brought through an 

 opening into a greenhouse in winter will soon start into growth while 

 the rest of the vine out of doors is frozen. In like manner the portion 

 of the trunk of an apple tree that is exposed to the direct rays of mid- 

 day sun may start into growth independently of the rest of the tree. 



Winterkilling. This may be confined to the twigs and flower 

 buds of fruit trees. Injury from this cause is most liable to occur in 

 valleys. On the adjacent higher land there may be comparative 

 immunity. Frosts are most likely to do injury in places where the 

 air is stagnant, especially in low spots where the air is not affected by 

 light winds and into which the cold air from the surrounding eleva- 

 tions drains. Such places are indicated when the first severe autumn 



