i;!() Food I'or. Plants. 



Experiments in 1912. 



Ill till' course oi' llic iii\"c'stii;atioiis ol' the wi-JtiTs on 

 llic control of apple powdery mildew in the Pajaro \'al- 

 ley, Cal., it became evident that the general vigor of the 

 tree and the thriftiness of the foliage growth had much 

 to do with the success of the summer spraying treatment 

 for the control of the mildew, and after a number of 

 experiments in ai)i)lying plant-food materials to the 

 foliage in the form of summer sprays, and after seeing 

 that certain crude-oil emulsions used as dormant sprays 

 had a marked effect in stimulating an increased vigor of 

 the trees the following spring, it was decided to try the 

 effect of a strong solution of Nitrate of Soda as a Aviuter 

 or dormant spray. Caustic potash (potash lye) was 

 also added for the purpose of giving the spray an insec- 

 ticide value. The mixture was prepared according to 

 the following formula: 



Nitrate of Soda 50 pounds 



Caustic Potasli 7 pounds 



\Vater 50 gallons 



The experiment was conducted in a Yellow Belltlower 

 apple orchard owmed by Mr. O. 1). Stoesser, of Watson- 

 ville, Cal. This orchard is situated about 5 miles from 

 the ocean shore and is in a district that is more subject 

 to ocean fogs and trade winds than is the main portion 

 of the Pajaro Valley. It is a common characteristic of 

 the numerous orchards of Yellow^ Belltlower apples of 

 this particular district that they bloom abundantly, but 

 set only a partial crop. The .trees are on a deep sedi- 

 mentary soil and grow wtII. 



Seven 12-year-old trees were sprayed on February 2, 

 1912. The application was very thoroughly made, so 

 that all of the small tw4gs were drenched. About 7 gal- 

 lons of spray solution were applied to each tree. Adjoin- 

 ing this row^ on one side was a check row^ of seven trees 

 which received no winter spraying, and on the other side 

 were several rows of seven trees each wdiich received 

 various applications of crude-oil emulsions and soaps. 

 For the i)urpose of gaining some idea of the effect of 



