THE TREE DOCTOR 235 



19 Crude Petroleum. 



Caution Use a fine nozzle and exercise great care to avoid 

 overspraying. It requires a careful workman to spray peach 

 trees with crude petroleum, as too much of the material, es- 

 pecially on the bodies of the trees, is likely to do harm. Lime- 

 sulfur-salt is quite as efficacious and safer to use than crude pe- 

 troleum. 



20 Lime, Sulfur and Salt. 



Stone lime, 15 to 30 Ibs. 



(Or dry air slaked lime or hydrate of lime one-fourth more). 

 Flowers of sulfur, 15 Ibs. 

 Salt, 15 Ibs. 

 Water, 50 gallons. 



Slake the lime in a small quantity of hot water, gradually 

 adding and thoroughly stirring in the sulfur. Dilute mixture 

 with twelve gallons of water and boil in an iron kettle or cook 

 by steam in a covered tank or barrel for one and one-half hour. 

 Then add salt, continuing the boiling for one-half hour more. 

 Fill vessel up with water to the required fifty gallons. Strain 

 the wash through a fine mesh strainer and apply hot. In using 

 an iron kettle keep the mixture vigorously boiling and thor- 

 oughly stirred to prevent caking and burning of materials. 

 Wash cooked by steam is more easily prepared and better made. 

 Apply the wash just as the buds begin to swell in the spring. 

 Cover all parts of the tree with a heavy coat of the wash. The 

 wash seems best adapted to orchardists who have not yet learned 

 to use petroleum with safety or are afraid that their trees are be- 

 ginning to show injury from the oil or will not stand many more 

 applications of it. It is especially recommended for the treat- 

 ment of peach trees for San Jose Scale. 



It is believed that the substitution for the salt of one and one- 

 fourth pound of blue vitriol dissolved in hot water results in a 

 quicker acting wash. This formula is known as the Oregon 

 Wash. 



