268 Appendix. 



SAN JOSE SCALE. 



By E. R. Bennett, Assistant Horticulturist Storrs Agricultural Experiment Sta- 

 tion, Storrs, Connnecticut. 



The increasing prevalence of San Jose scale in this State may warrant an- 

 other discussion of its treatment by farmers and fruit growers despite the ex- 

 tent to which the subject has already been discussed. 



The question now is not so much what treatment will kill the scale, as what 

 treatment may be used to kill it at the least cost and at the same time not in- 

 jure the trees. Kerosene oil, crude petroleum, whale-oil soap, hydrocyanic acid 

 gas, and sulphur, lime, and salt solution have all been used with success. Of 

 these remedies the sulphur, lime, and salt solution has recently become the 

 most popular, because of its ability to destroy the scale without injuring the 

 trees. 



In investigating this subject during the past season we had an opportunity 

 to assist in the spraying of 11,000 peach and plum trees on the farm of 

 Mr. J. II. Hale at South Glastonbury, Connecticut. 



Work was begun in the field on March 10, 1903. The equipment included 

 one 20-horse power steam boiler with steam pipes leading from the boiler into 

 six barrels. Four of these were used for boiling the sulphur, lime, and salt, 

 and two for heating water. A near-by hydrant supplied water for filling 

 the boiler and making the solution. Two pumps mounted on 50-gallon barrels 

 were used, each pump having two lines of hose fitted with double Vermorel 

 nozzles. Later a third pump was added to the equipment to avoid loss of time 

 from the pumps getting out of order. Other nozzles were tried, but none gave 

 as good satisfaction as the medium or Bordeaux size aperture of the Vermorel. 



Three men and a horse were used for each pump. Two men made the 

 solution, and when the trees to be sprayed were far away from the boiler, a man 

 with a horse and wagon hauled the solution to the pumps. In all, the force con- 

 sisted of nine men and three horses. Power sprayers were not used, because, 

 since more than two lines of hose could not be operated to advantage, and 

 the driver could easily furnish sufficient pressure at the pump, the additional 

 cost of purchasing and running a power sprayer was not advisable. 



DETAILS OP MAKING THE MIXTURE. 



The mixture was made in several different ways : 



First. — Thirty pounds of lime was slaked with boiling water and reduced to 

 a pasty mass. Then thirty pounds of sulphur was added and thoroughly mixed, 

 after which enough water was added to thin the material, and the steam was turned 

 on. After boiling about one hour, fifteen pounds of salt was added, and the whole 

 mass was boiled fifteen minutes more. Then the barrel was filled with hot water 

 and drawn off into the pump barrel, from which it was applied to the trees. 

 This formula made a good solution, but was expensive and so thick that the 

 pumps clogged somewhat. 



Second. — A formula of twenty pounds of lime, twenty pounds of sulphur, and 

 fifteen pounds of salt to fifty gallons of water, was next tried. This appeared 

 to work better with the pumps and made a good coat on the trees, but a considerable 

 residue of sulphur was left in each barrel, indicating that not enough lime 

 was used to dissolve all the sulphur. 



