134 



ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



merely of cutting off the top at a point 

 where it is desired to form the head. 

 With most varieties the head should be 

 started not more than two feet above the 

 graft union, but in some naturally spread- 

 ing varieties, like Rhode Island Greening, 

 for example, the head would be much bet- 

 ter started at a point three feet from the 

 ground. With trees two or more years 

 old the heads, which have been formed in 

 the nursery row. are often too high. * In 

 such cases the entire head should be re- 

 moved and the trees induced to form new 

 heads. If the heads are in the proper 

 position, the necessary pruning consists 

 simply in cutting out unnecessary • 

 branches and in cutting back the remain- 

 ing three or four branches to within about 

 six or eight inches from the stem. 



See article by A. B. Capps. "Heading Trees in 

 Nursery." If Mr. Capps' methods were used 

 It would be unnecessary to prune the top at 

 all.— Ed. 



Treatment of Nursery Stock for San 

 Jose Scale 



The San Jose Scale. The reputable 

 nurserymen are very careful to keep their 

 stock free from scale, and most of them 

 are provided with a fumigating house for 

 the purpose and fumigate all their trees 

 before they send them to their customers. 

 Notwithstanding these precautions, the 

 introduction of the scale into unintested 

 sections may usually be attributed to the 

 planting of infested nursery trees. The 

 most careful examination is not sufficient 

 to detect the presence of scale, tor the in- 

 sects often hibernate in small crevices in 

 the bark and under bud scales. Before 

 planting the trees in uninfested sections 

 it is therefore important that they should 

 be either refumigated or dipped. The 

 expense in connection with the fumigation 

 or dipping is very insignificant compared 

 with the cost of spraying the trees a few 

 years later. 



Fumigating 

 Fumigating nursery stock consists in 

 subjecting the trees to the fumes of hydro- 

 cyanic acid gas tor a period of 30 to 45 

 minutes. The gas is made by using the 

 following chemicals: 



• The terms "high" or 'low" heading are 

 relative and of course vary with the circum- 

 stances and the nature of the tree. — Ed. 



■^ater ^ fluid ounces 



Sulphuric acid (high grade, 



66° Baume) 2 fluid ounces 



Potassium Cyanide (98-100 



purity) 1 ounce (av.) 



This quantity is required for every 100 

 cubic feet of space. A tight box about 

 six feet long by four feet wide and four 

 feet deep, will answer the purpose. It 

 should be supplied with a tight fitting 

 cover the full size of the top, and ad- 

 justed so that it can be opened from a 

 distance. (See Fig. l.) The box should 



Fig 1. A Home-made Fumigating Box for 

 the Treatment of Nursery Stock. 



also have a small slide door located at the 

 bottom near the center. It is through 

 this door that the chemicals are intro- 

 duced. The acid and water are mixed to- 

 gether and placed in position, and when 

 everything is in readiness the cyanide is 

 dropped into the liquid and the small door 

 quickly closed. When the time is up the 

 top should be removed by means of a rope 

 through a pulley-block suspended above. 

 The fum.es are extremely poisonotis and 

 should not be inhaled. 



The process of dipping fruit trees is 

 probably more satisfactory tor general use 

 among fruit growers than fumigation. 

 Nurserymen, and others who are familiar 

 with the use of potassium cyanide for 

 this purpose, will probably find fumiga- 

 tion more convenient. While injury may 

 follow either method, if the necessary pre- 

 cautions are not observed, there is less 

 risk with the dipping process. Either the 

 lime-sulphur wash or miscible oil may be 

 used for dipping. The former is some- 

 what troublesome to prepare, and in view 

 of the small quantity required for this 

 purpose the trouble would be unwarranted. 

 Some of the prepared lime-sulphur solu- 

 tions on the market have given good re- 



