Food for 



Winter Spraying With Solutions of Nitrate Plants 



of Soda 175 



By W. S. BALLARD, Pathologist, Fruit-Disease Investigations, 

 Bureau of Plant Industry, and W. H. VOLCK, County Horticul- 

 tural Commissioner of Santa Cruz County, California. 



These investigations were conducted in co-operation between the Office of Fruit- 

 Disease Investigations of the Bureau of Plant Industry and the Office of the 

 County Horticultural Commissioner of Santa Cruz County, located at Watson ville, 

 Cal. The writers' names Appear above in alphabetical order. 



Introduction 



Recently several investigators have reported re- 

 sults in shortening the rest period of a number of woody 

 plants by immersing the dormant shoots in weak 

 nutrient solutions or by injecting solutions of alcohol, 

 ether, and various acids into the twigs. These experi- 

 ments have been conducted in the laboratory with 

 short cuttings of the plants. The effect of such treat- 

 ment has been to force the dormant buds out several 

 days ahead of the normal opening period. 



During the last two years the writers have obtained 

 similar and additional results on a much larger scale 

 by spraying dormant fruit trees with strong solutions of 

 certain commercial fertilizers, especially Nitrate of 

 Soda. Since these experiments have been conducted 

 on the entire trees in the orchard, it has been possible 

 to observe the effects throughout the whole season. 

 The investigations have not yet been carried far enough 

 to permit drawing any conclusions regarding the 

 physiologic action of such spraying, but because of its 

 practical value these preliminary results seem deserving 

 of attention at this time. 



Experiments in 1912 



In the course of the investigations of the writers 

 on the control of apple powdery mildew in the Pajaro 

 Valley, 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 spray- 

 ing treatment for the control of the mildew, and after 



