EXPERIMENTS WITH DRY BORDEAUX. 7 



been sprayed once, on June 28, with Bordeaux mixture and 

 Paris green. One acre was dusted with 8 pounds of dry Bor- 

 deaux mixture on the following dates: July 5, 13, 20 and 28; 

 August 3, 10, 16, and 22. July 5 and 13, Paris green was used 

 with the Bordeaux. At no time were there potato bugs of any 

 amount on the vines, nor did the flea beetle do any appreciable 

 damage. Late in August there were more plant lice than usual, 

 but not enough to damage the vines at all seriously. During the 

 growing season there was no appreciable difference in the 

 appearance of th^ dusted from the sprayed, except the dusted 

 were lighter in color and the vines were less broken in the latter 

 part of the season by the man walking through than by the 

 horses on the sprayer. The darker color of the sprayed acre 

 was more conspicuous at a distance and was doubtless due to the 

 adhering Bordeaux mixture. At digging, the vines were dead 

 on both plots from frost. At no time was there blight of any 

 amount upon either acre. The yields were as follows : 



Yield of potatoes upon one acre sprayed with regular Bor- 

 deaux and a corresponding acre dusted with dry Bordeaux. 

 The fungicides were applied nine times during the season. 



Large Small Rotten 

 bbls.* bbls. bbls.f 



Regular Bordeaux mixture 122 17 none 



Dry Bordeaux mixture 114 17 5 



From the above results it would seem that the dry Bordeaux 

 applied to dry vines is not effective in preventing blight and 

 subsequent rot. It will be tested another season on damp vines 

 to see if it is of value as a fungicide in garden culture of 

 potatoes. 



A Kansas manufacturer of dusting apparatus claims that 

 ready prepared Bordeaux mixture is inert and that satisfactory 

 results can be obtained by dusting on a mixture of finely pulver- 

 ized copper sulphate and lime. The claim is made that these 

 materials react as soon as moistened by dew and that the Bor- 

 deaux mixture thus freshly formed is as effective as the regular 

 Bordeaux mixture applied as a spray. This will also be tested 

 another season. 



*One barrel is 23 bushels or 165 pounds. 



t All discolored potatoes are included under rotten. 



