296 MAIMS AGRICULTURAL EXPERIMENT STATION. I907. 



part to the addition of the sodium benzoate. It seems reason- 

 able to assume that the latter was of some value, for as is shown 

 elsewhere sodium benzoate apparently reduced the amount of 

 scab where seed tubers were treated with a solution of it, and 

 its value as a preservative in preventing the growth of the ordi- 

 nary saprophytic fungi is well known. 



The foregoing account and discussion is based wholly on 

 the Station experiments at Foxcroft, where every endeavor was 

 made to give the dust sprays a fair and impartial trial. Before 

 leaving the subject it should be mentioned that a large number 

 of dust machines were used the past season around Maple Grove 

 and Ft. Fairfield. While there was considerable difference of 

 opinion, a number of growers there expressed themselves as 

 well satisfied with the results obtained from dusting. The 

 writer on August 22 spent nearly the entire day driving from 

 one field to another in this locality and was convinced that at 

 this time the dust was of considerable value in keeping the 

 blight in check. However, there was very little opportunity 

 for accurate comparisons. With one or two possible exceptions, 

 there were no fields or parts of fields lying side by side where 

 both had otherwise been treated alike and one sprayed with 

 dust and the other with wet bordeaux the same number of 

 times on approximately the same dates. No unsprayed checks 

 were left in any case. Many cases were found also both with 

 the dusting and wet spraying where it seemed evident that the 

 applications were not begun till after the blight had become well 

 established on the plants. 



Attempts were made in the spring to arrange for cooperative 

 dusting experiments in this locality but without much success. 

 Most of the owners of the dust machines were so thoroughly 

 convinced of the value of the method from the experience of 

 the previous year that they did not wish to bother with the wet 

 bordeaux sufficiently to spray a part of their fields in this way 

 and keep the necessary records. One gentleman did attempt 

 this but unfortunately waited too long before beginning spray- 

 ing, and neglected to keep a record of the dates when he did 

 spray. On August 22 both parts of this field showed more or 

 less blight, but one was about as bad as the other. A later visit, 

 September 19, the day following a severe frost, indicated that 

 the wet sprayed tops remained green somewhat longer than 



