366 Elementary Principles of Agriculture 



which are added arsenate of lead to control the later broods of the 

 codling moth, and the fungus diseases previously mentioned. 



544. The Cultivated Stone Fruits include the peach, 

 apricot, nectarine, plum and cherry. The fruits are 

 usually well colored, and highly flavored when ripe. 

 They are firm up to the full ripening period at which time 

 they develop a high content of sugar and become soft. 

 They may be gathered when mature, but before ripening, 

 and transported long distances, especially in refrigerator 

 cars. The ripening process goes on after the fruit is 

 gathered. The stone fruits are usually propagated by 

 budding and the trees set into the orchard at one year 

 from the bud, in rows 12 to 18 feet apart. The young 

 trees are headed back to a short stem 15 to 24 inches from 

 the ground. The annual pruning is not a cutting-out pro- 

 cess, as in the pome fruits, but a heading-in of the branches 

 by cutting off their ends. This makes the branches 

 stouter and better able to support the crop of fruits. 

 (See If 188.) The curculio and the brown rot (Fig. 91) 

 are the most generally serious diseases to stone fruits. 

 Spraying with self-boiled, lime-sulfur wash affords pro- 

 tection from the brown rot, and when combined with 

 arsenate of lead, also the curculio. 



545. Frost Injury. The stone fruits are subject to 

 winter killing of buds, and even branches in the central 

 and northern states. A few warm days will cause early 

 blooming, with consequent danger of injury by late frost. 

 For this reason the site for peach or plum orchards should 

 be preferably located on ridges or elevated flats with steep 

 slopes into near-by valleys. In such situations the cool 

 air drains off at night, and as a rule trees in such situations 

 are later in flowering than they would be in the valleys, 

 and hence will oftener escape frost injury. 



