16 Farmers’ Bulletin 1225. 
YIELDS. 
It has been found that the yield of sprayed fields of early potatoes 
may be increased over 100 per cent above the yield of unsprayed 
fields, and the yield of sprayed fields of late potatoes increased over 
50 per cent above the yield of unsprayed fields, by the use of Bordeaux 
mixture against the potato leafhopper and “‘hopperburn.”’ 
SUMMARY OF CONTROL MEASURES. 
Spraying appears so far to be the best practical method of control 
for the potato leafhopper and for preventing the appearance or spread 
of ‘“hopperburn.”’ 
Fic. 14.—Details of sprayer shown in figure 13: 1, Hose connection; 2, handle to assist in holding and 
directing rod; 3, adjustable booms and nozzles, side view; 4, same, front view. 
Bordeaux mixture 4—4—50 is the best spray to use. 
It should be applied to the underside of the leaves thoroughly, at 
least 150 pounds pressure being used so that a fine mist spray will 
result. 
Make at least three applications, and spray a fourth time if neces- 
sary to keep down ‘“‘hopperburn” until the crop has matured. 
To make the application thorough, spray both sides of each row. 
WASHINGTON : GOVERNMENT PRINTING OFFICE: 1921 
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