PICKERING SPRAYS. 



19 



sprayed with Pickering (A) and (C) sprays varied markedly. On an 

 average more copper was found on the leaves sprayed with Pickering 

 (C) sprays than on those treated with Pickering (A) sprays. 



Table 5. — Adherence of copper from various sprays to potato leaves (northern Maine). 





Spray. 



Cop- 

 per 

 sul- 

 phate 



in 

 spray. 





Copper adhering to leaves. 







Plat 



No. 



Parts per million 

 (dry basis). 



Parts per mil- 

 lion per 0.1 

 per cent 

 CuSOdn 

 spray (dry 

 basis). 



Mg. per 

 square meter 

 ofleafsurface. 



Mg. per 



square meter 



ofleafsurface 



per 0.1 per 



cent CuS04 



in spray. 





Lot l.« 



Lot 2.2 



Lotl.i 



Lot 2.2 



Lot l.» 



Lot 2.2 



Lot I.' 



Lot 2.2 



1916. 



Standard Bordeaux, 

 5-5-50 



Per 

 cent. 

 1.25 

 .64 

 .38 

 .13 

 .065 

 .23 

 .115 

 .36 



.38 

 .38 



.7 

 .6 

 .6 

 .5 

 .5 

 .4 

 .4 

 .3 



.5 



.5 



.5 

 1.25 



163.3 

 149.7 

 29.4 

 35.8 

 9.11 

 42.9 

 36.6 

 61.8 



120.8 • 

 73.6 



519.8 

 455.1 

 422.6 

 338.1 

 277.5 

 274.2 

 111.9 

 138.6 



141.4 



128.9 



213.3 



387.4 



332. 6 

 53.7 

 22.3 

 19.6 

 7.2 

 23.8 

 18.9 

 97.9 



54.0 

 38.0 



571.7 

 533.9 

 373.6 

 431.5 

 334.5 

 319.3 

 200.5 

 163.3 



338. 



275.0 



390.0 

 1,073.7 

 41.8 

 22.05 

 956. 19 

 1,641.60 

 1,098.0 

 16.9 

 878.3 

 1,217.5 

 1,703.0 



1,700 

 1,100 

 1,700 

 1,500 

 1,200 

 2,300 



13.0 

 23.4 

 7.7 

 27.6 

 14.0 

 18.7 

 31.8 

 17.2 



31.8 

 19.4 



74.2 

 75.8 

 70.4 

 69.6 

 55.5 

 68.6 

 28.0 

 46.2 



28.3 



25.8 



42.7 

 31.0 



26.6 

 8.4 

 5.9 

 15.1 

 11.1 

 10.3 

 16.4 

 27.2 



14.0 

 10.0 



81.7 

 89.0 

 62.3 

 86.3 

 66.9 

 79.8 

 50.1 

 54.4 



67.6 



55.0 



78.0 

 86.0 



31.15 



15.77 

 8.00 



11.64 



.80 



7.97 



5.99 



12.80 



24.13 

 5.98 



11.17 

 10.64 

 10.96 

 6.98 

 5.34 

 6.25 

 2.11 

 3.32 



2.96 



2.66 



4.38 

 7.55 



18.61 

 13. 07 

 10.39 

 14.13 

 8.96 

 9.10 

 7.00 

 3.97 



9.24 



8.57 



10.02 

 30.00 



2.5 

 2.4 

 2.1 

 9.0 

 1.2 

 3.5 

 5.2 

 3.6 



6.4 

 L6 



1.60 

 1.77 

 1.83 

 1.40 

 1.07 

 1.56 

 .53 

 1.11 



.59 



.53 



.88 

 .60 





















do 



do 



Pickering (C) 













do 



Pickering (A) and 

 rosin-fish-oil soap. . . . 





1917. 

 1 



\ 



Pickering (A) 



2.66 



2 





2.18 



3 



Pickering (C) 



1.73 



4 





1.83 



5 





1.80 



6 



do 



1.82 



7 



Pickering (C) 



' 1.78 



8 



do 



1.32 



12 

 13 

 14 



Check. 



Pickering (A) and 

 rosin-fish-oil soap 



Pickering (A) and 

 lead arsenate 



Pickering (C) and 

 lead arsenate 



Bordeaux, 5-5-50 



1.85 



1.71 



2.00 

 2.40 



Check. 





















Check. 



Bordeaux, 3-3-50 



Bordeaux, 5-5-50 



Bordeaux, 3-14-50 



.75 



1.25 

 .75 



363.0 

 566.4 

 618.1 



48.4 

 45.3 

 82.4 



127.5 

 131.3 

 146.4 



5.87 

 22.12 

 11.41 



31.71 

 48.74 

 31.44 



.78 

 1.77 

 1.52 



4.23 

 3.90 

 4.19 







.7 

 1.25 

 1.25 



.7 



.7 



1.0 



1.0 



1.0 



1.25 



.6 



.6 



.6 



.6 



.6 



271.4 



38.8 



236 



200 

 195 

 185 

 140 

 180 

 217 

 233 

 233 

 200 



150 



125.5 

 97.4 

 136.4 



243 

 157 

 170 

 120 



184 



5.86 



21.37 

 36.19 

 51.57 



.84 



3.05 





Burgundy mixture 



Bordeaux, 5-5-50 



2.89 







4.13 



1918. 

 1 



1,650 

 1,400 

 1,950 

 1,850 

 1,400 

 2,250 

 1,300 

 1,400 

 1,400 

 1,200 



900 





2 













3 



Bordeaux, 4-4-50 



Bordeaux, 4-2-50 



Bordeaux, 4-1-50 



Bordeaux, 5-5-50 











4 











5 











6 











A 













C 

















D 

















E 

















F 



Copper sulphate and 

 lead arsenate 





























1 In 1916, picked two days after spraying, and in 1917, eight days after spraying. 



2 In 1916, picked seven days after spraying, and in 1917, two days after spraying. 



IN 1917. 



Leaves picked on August 11, eight days after spraying Got 1) and 

 on August 24, two days after spraying (lot 2), were analyzed with the 

 results shown in Table 5. 



