15 



venient. The boiling due to the slaking of the lime thoroughly 

 mixes the ingredients at the start, but subsequent stirring is neces- 

 sary if the wash is cooked by direct heat in kettles. If cooked by 

 steam no stirring mil be necessary. After the wash has been pre- 

 pared it must be well strained as it is being run into the spray pump 

 or tank. The wash may be cooked in large kettles or preferably by 

 steam in barrels or tanks. 



Miscihle oils. — Under the head of miscible oils are designated 

 several commercial insecticides coming into considerable use as sprays 

 for scale insects during the dormant period of the trees, and their 

 use will often be advantageous, especially where but a few trees are 

 to be treated. Miscible oils should be used on dormant trees at the 

 strength recommended by the manufacturers. 



Commercial lime-sulpJiur washes. — There are on the market several 

 brands of concentrated lime-sulphur solutions, designed to replace 

 the homemade lime-sulphur wash, mentioned above. These washes 

 in general have proved to be satisfactory for the control of the San 

 Jose scale, and will doubtless be about as effective against the 03"ster- 

 shell and scurfy scales as the homemade wash, the preparation of 

 which may thus be avoided if desired. These may be used on dor- 

 mant trees, or, much more dilute, on trees in foliage. 



Approved : 



James Wilson, 



Secretary of Agriculture. 



Washington, D. C, 2Iarch 30, 1910. 



[Cir. 121] 



O 



