Diseases and Pests of the Apple and Their Control 245 



1 to 1,000. Soap should be added at the rate of 2 of 3 

 pounds to 50 gallons to increase the spreading and adhesive 

 qualities of the spray. Nicotine may be used in combina- 

 tion with lead arsenate, lime-sulfur or both. 



Miscible oils. — " Miscible " or " soluble " oils have 

 come into considerable use as dormant sprays, particularly 

 in the West where they have been found a satisfactory 

 treatment for badly encrusted San Jose scala The misci- 

 ble oils have a tendency to spread after they have been 

 applied and for that reason are particularly effective 

 against scale insects. Home-made emulsions are used to 

 some extent in California where the crude oils can be pur- 

 chased cheaply. The question of injury resulting from 

 continued oil spraying is disputed. It is advisable to make 

 dormant oil spray in the late winter rather than in the fall. 

 If oil sprays can be applied in the spring just previous to 

 the swelling of the buds, preferably on sunny days, the 

 danger of injuring the trees will be minimized. When 

 hard water is being used for spraying, it is desirable to add 

 1 to 2 pounds of soda to each spray tank. 



So-called dry lime-sulfur. — The active and killing 

 ingredients of lime-sulfur determine the value of these 

 sprays. The following table gives the relative cost of this 

 liquid versus dry liine-sulfur compounds measured in 

 terms of active sulfur. The comparison in this table is in 

 favor of the liquid lime-sulfur. In lime-sulfur (dry), the 

 active sulfur costs $18.90 for 100 pounds; in soda-sulfur 

 $14.03 for 100 pounds, and liquid lime-sulfur only $8.03 

 for 100 pounds. The inference is clear that lime-sulfur 

 solution is a much more economical form than the so- 

 called dry lime-sulfur or soda-sulfur. 



