18 



BULLETIN 550, U. S. DEPARTMENT OF AGRICULTURE. 



On all sprayed plats where poison with adhesive had been applied 

 with " trailers" the control was effective. Plats I and II on which 

 arsenate of lead (paste) had been applied at the rate of 3 pounds to 

 50 gallons of liquid were infested more heavily than Plats III and IV, 

 on which arsenate of lead at the rate of 5 pounds to 50 gallons had 

 been applied. The infestation was naturally heavier on the west 

 side, however, as is shown by a comparison of the unsprayed plats. 

 Double spraying appeared to reduce the infestation but not enough 

 to offset the extra cost of application. 



EXPERIMENT IN THE MILLER AND CARLBURG VINEYARD, NORTH EAST, PA., 1915. 



The experimental plat in this vineyard included 64 rows covering 

 about 10 acres. It was divided into 10 plats of 6 rows each, the 

 4 remaining rows being left for check. This plat was surrounded on 















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Fig. 4. — Diagram showing arrangement of experimental plats in the vineyard of Messrs. G. H. Miller and 

 A. I. Carlburg, North East, Pa., 1915. The sprayed plats are marked with Koman numerals and the 

 check plats with letters. (Original.) 



all sides by vineyard, two parts of which were used as checks also. 

 The arrangement of plats is shown in the diagram (fig. 4). Spraying 

 operations for both first and second applications in this vineyard 

 were interrupted and delayed by frequent rains. 



Table 8.- 



-Spray mixtures used and methods and dates of application in experimental plats, 

 Miller and Carlburg vineyard, North East, Pa., 1915. 





Dates of 



spraying. 



Arse- 

 nate of 



lead 

 (paste). 



Bordeaux mix- 

 ture. 



Laun- 

 dry 



soap. 



Fish- 

 oil 



soap. 



Flour 

 paste. 



Nico- 

 tine 

 sul- 

 phate. 



Water. 



Method of ap- 

 plication. 



•lat No. 



Lime. 



Copper 



sul- 

 phate. 



I 



July 2, 15 

 July 2, 15 

 July 2, 15 

 July 3, 16 

 July 3, 16 

 July 3, 16 

 July 3, 17 

 July 5, 17 

 July 5, 17 

 July 5, 17 



Pounds. Pounds: Pounds. 

 3 8 3 



Pounds. 



1 



Pounds. 



Pounds. 



Pints. 



Gallons. 

 50 

 50 

 50 

 50 

 50 

 50 

 50 

 50 

 50 

 50 



"Trailers." 



II... 



5 

 3 

 3 

 3 

 3 



3 

 3 

 3 



3 



3 



2 

 2 







Do. 



Ill i 







Do. 



IV 



3 

 3 

 3 

 3 

 3 

 3 

 3 



3 

 3 

 3 

 3 

 3 

 3 

 3 



1 



1 



1 







Do. 



V 



VI.. .. 



2 









Do. 

 Do. 



VII.. 







Do. 



VIII 





2 





Do. 



IX... . 







Do. 



X... 





2 







''Set nozzles." 











i Rain followed immediately after the second spray application on this plat and apparently washed ofl 

 most of the spray. 



