New York Agricultural Experiment Station, 123 



unsprayed rows in the experiment field. Undoubtedly, it was this 

 third spraying which gave Series I its protection against late blight. 

 Probably the results would have been better if it had been made two 

 or three days earlier. 



Series II. — This series consisted of rows 2, 5, 8, 11 and 14. The 

 plants were sprayed five times — July 7, 21, August 7, 21 and Sep- 

 tember 3. At the time of the first spraying the plants were six to 

 eight inches high. On this series it was necessary to use poison^ 

 but once, namely, in the second spraying, July 21. The early spray- 

 ing of July 7 seems to have discouraged the " bugs " so that as late 

 as July 21 there were but few of them on this series, although they 

 were abundant on the other two unsprayed series a week earlier. 

 Two days after spraying with bordeaux and white arsenic there were 

 no live " bugs " and no injury to the foliage. 



Up to the time of the fourth spraying, August 21, no trace of late 

 blight had been found anywhere in the experiment field, but it made 

 its appearance three days later. The fifth spraying, September 3, 

 was made while the blight epidemic was at its height. According 

 to our plan for spraying this series regularly every two weeks a sixth 

 spraying should have been made September 17, but the plants were 

 so much blighted that it was thought it would not pay to spray them 

 again. 



Series III. — Series III consisted of rows 3, 6, 9, 12 and 15. They 

 were not sprayed at all with bordeaux but were treated twice (July 

 14 and 28) with white arsenic in lime water to kill the " bugs." The 

 white arsenic was used at the same rate as on Series I and II ; that 

 is, one quart of stock solution to 50 gallons of lime water. 



Three days after the first treatment nearly all of the plants showed 

 slight injury. It appears that too little lime was used with the 

 arsenic. The quantity was not measured, but guessed at, and was 

 thought to be ample. In the second treatment care was taken to 



° White arsenic, one quart stock solution to 50 gallons of bordeaux. 



