A Bacterial Disease of Stone Fruits 433 



had been cut back and not fertilized was much improved, not over two 

 or three per cent of the leaves had fallen, and the twigs on very few of 

 the trees contained cankers. 



Chandler,^ in a series of commercial fertilizer experiments conducted 

 at Brandsville, Missouri, from 1910 to 1912, also has shown that the 

 organism can be controlled to a large extent by the use of fertilizer. He 

 obtained excellent results in using from 700 to 800 pounds of complete 

 fertilizer per acre on mature trees and from 300 to 400 pounds on trees 

 from two to three years old. Applications were made once a year in early 

 spring or in June. Those made in June apparently gave better results 

 than those made in spring. Chandler's results show that nitrate of 

 soda is the essential element for controlling the disease. All plots that 

 received nitrate of soda, whether alone or in combination with either 

 potassium chloride or acid phosphate or both, shoAved very great resistance 

 to the disease, but the plots receiving only potassium or phosphorus or 

 both did not show any increased resistance. In the plots treated with 

 nitrate of soda a few leaves were affected, yet very few fell as the result 

 of the disease and the foliage had a healthy color. In some cases the 

 trees of the check plot and those treated with potassium chloride and 

 acid phosphate lost as high as fifty per cent of their leaves. 



An application of manure well worked into the soil gives excellent results 

 and in some cases the improved condition of the trees is more permanent 

 than when commercial fertilizer alone is used. Good results have been 

 obtained by seeding down the orchard permanently to red clover after 

 a liberal application of manure. The clover is cut from time to time and 

 allowed to rot under the trees. This practice, however, has disadvantages 

 and cannot be recommended for general use. Very good results have been 

 obtained also by following an application of manure with cowpeas. The 

 tops are not cut but are allowed to stand until killed by frost, and the 

 following spring the dead material is carefully worked into the soil. After 

 the first year commercial fertilizers and cowpeas are used, hxit if the trees 

 show marked improvement nitrate of soda is omitted from the fertilizer, 

 since the cowpeas as a rule furnish sufficient nitrogen. This method 

 gives good results. The peas, however, furnish an abundant food supply 

 for mice, which are likely to injure the trees during the winter. 



'" Chandler, W. H.. in a letter to the writer dated September 26, 1912, containing a summary of some of 

 lii-: eommercial fertilizer experiments with peach trees. A detailed account ol the experiments will 

 finally be published by the Missouri Experiment Station, Columbia, Missouri. 



