79 



cation of a spray, and the tree being dormant is less liable to 

 injury by strong sprays than during the growing season. 



A number of materials have been used in spraying for the 

 San Jos^ scale, but at the present time only three or four ap- 

 pear to have any great value. These are the lime-sulfur 

 wash, miscible oils, and dry sulfur compounds. The lime- 

 sulfur wash is now usually purchased in concentrated liquid 

 form and diluted with water for use, the amount of dilution 

 being generally about one of the wash to eight or nine of 

 water, according to directions sent with it. For best results 

 though, its density should be determined with a Beaume hy- 

 drometer, and the amount of water to add will vary with 

 the density of the wash. Tables giving the amount for the 

 different densities can be obtained from the Agricultural Ex- 

 periment Station at Amherst, and almost any drug store can 

 obtain a Beaume hydrometer for liquids denser than water at 

 a cost of not more than a dollar or two. 



Spraying with the properly diluted material can be made at 

 any time during the winter or spring until the buds begin to 

 open, but somewhat better results are obtained by spraying 

 as late as possible. 



The miscible oils are also nearly always purchased ready 

 made, needing only dilution with water. They have one ad- 

 ' vantage over the lime-sulfur wash in that they spread over 

 the surface of the bark more from where they strike it. On 

 the other hand, many cases of injury to trees have been re- 

 ported following the use of these materials, particularly where 

 they are used spring after spring for several years. How 

 serious this injury is cannot be said to have been fully deter- 

 mined as yet, but there is certainly some liability to it, and 

 many fruit growers now follow the practice of spraying with 

 lime-sulfur for two years and use the oil every third year 

 only. 



The inconvenience of shipping liquid materials, and other 

 difficulties involved, has led to the recent appearance on the 

 market of dry sulfur compounds, these being for the most 

 part combinations of sulfur with lime, barium, magnesium or 

 sodium. From the standpoint of convenience these are much 

 better than the liquid lime-sulfur concentrate, but chemical 



