16 



BULLETIN 837, U. S. DEPARTMENT OF AGRICULTURE. 



pounds to 50 gallons, equivalent to 5 pounds of paste to 50 gallons, 

 as a basis for comparison that year. The 1^-pound rate was used 

 in but two vineyards in 1916. In 1917 the 2|-pound rate was retained 

 in four vineyards and the 1^-pound used in seven. In 1918 compari- 

 son was made between 1 pound and 1^ pounds of arsenate of lead 

 powder. 



Table VI. — Relative efficiency of arsenate of lead at the rate of 1, 11, and 2\ 

 pounds (powder) to 50 gallons liquid. 1 





Spray appli- 

 cations. 









Percentag 



; of infested grape berries. 





ft 



03 



ja 



Catawba va- 

 riety. 



Concord va- 

 riety. 



Ives variety. 



Pounds of arsenate lead 



a> 



3 

 o . 



cS 

 >> 













powder to 50 gallons 

 liquid 















lO 



w at 

 11 







3 

 V 

 o 

 u 



03 

 ft 

 o 

 o 



6 



- 03 



_C3 

 ft 



■3 



s 



,3 



03 

 ft 

 ■3 

 >> 



o 



<D 



,3 

 o 



a 





o 

 a) 



o 

 +^> 

 3 







<c 



a 



g 



» 



03 







03 





o3 





-M 



■3 



3 



3 



a 



M 



■3 



& 



■3 



h 



■3 





CO 



£ 



% 



> 



02 



<1 



w 



<i 



K 



<! 



SEASON 1916. 





{I 



X 

 X 



2 



3 



4 

 6 



0.93 

 11.90 



81.12 

 70.26 











1J 



5.56 



52.83 



















2 



3 





6.42 



75.69 



5.56 



52.83 









{I 



X 

 X 









2 



3 



4 

 6 







3.25 

 3.34 



64.52 

 43.32 







2i 



10.41 



64.39 



















2 



3 





10.41 



64.39 



3.30 



53.92 

















SEASON 1917. 





f X 

 X 

 X 

 X 

 X 

 X 

 X 



X 

 X 

 X 

 X 

 X 

 X 

 X 







1 

 2 

 3 

 4 

 5 

 6 

 7 



2.03 

 8.86 



64.09 

 78.17 































0.47 



61.61 







1J 







5.84 



63.03 













.84 



.18 



2.66 



32.11 

 20.60 

 88.03 



0.43 

 2.94 



20.14 









1.48 



42.00 



19.59 



























7 



10 





4.55 



61.82 



1.04 



50.59 



1.68 



19.86 





If 



X 

 X 

 X 

 X 











1 



2 

 4 

 6 



.67 

 6.47 



7.72 



64.09 

 79.31 

 79.63 

























"1 





















.48 



30.14 



2.11 



39.67 

















4 



5 





4.95 



74.34 



.48 



30.14 



2.11 



39.67 











SEASON 1918. 





f X 



If 



X 

 X 

 X 

 X 







1 

 2 

 3 

 4 







1 



0.86 



7.85 









4.78 



68.02 













0.41 



1.00 



2.54 

 6.28 





































4 



4 





4.78 



6S.02 



.71 



4.41 



.86 



7 85 





{i 



X 

 X 











1 

 2 











2.08 



6.93 









7.39 



62.36 

























2 



2 





7.39 



62.36 





2.08 



6 93 













* All plats received Bordeaux 2-3-50 and resin soap 1 pound to 50 gallons in 1917 and 1918. Same in 1916, 

 except laundry soap 2 pounds to 50 gallons, first application; and second application vineyards Nos. 5 and 6. 



