SUPPLEMENTS FOR COPPER FUNGICIDES 



105 



cent of soap increased the adliesiveness of Bordeaux; Cliuard and Porchet 

 (14), that soap increased adherence on grapes; Shear (83), that rosin fish-oil 

 soap increased the adhesiveness of Bordeaux on cranberries; Hawkins (39, 

 40 p. 19), that rosin fish-oil soap increased the adherence of Bordeaux on 

 grape leaves, and that 0.50 per cent of fish-oil soap and rosin fish-oil 

 soap increased the adherence of Bordeaux 4-2-50 on grape berries (40, 

 p. 25); and Washburn (95), that 1.50 per cent of whale-oil soap or soft 

 soap increased both spreading and adhesiveness of Paris green. Dye and 

 Newhall (23) found that 2 pounds of resin-fish-oil soap in 50 gallons 

 increased the adhesiveness of Bordeaux 5-5-50 to celery and possibh' 

 served as a spreader. Berger (4) claimed that 3 per cent of linseed oil 

 increased the sticking of Bordeaux 8-8-50; the Iowa Experiment Station 

 (45), that small amounts seemed effective with Bordeaux; and Hood (44), 

 that 1 pint of linseed or fish oil in 50 gallons increased substantially the 

 adherence of lead arsenate. Degrully (20) advocated silicic sol as a sticker 

 for copper sprays. 



The work of Cuba of this Station with basic copper sulfate was con- 

 ducted largely in the greenhouse on cucumbers and tomatoes with artifi- 

 cial rain, but also in the field with cucumbers and celery. In many in- 

 stances the copper on a given area of leaf surface was determined in the 

 laboratory by electrical deposition and calculated to 100 square inches, 

 although substantially all of the deposit was on the upper surface. In some 

 cases there was considerable variation in- the amount of copper in dupli- 

 cate applications due to unequal distribution, the impossibility of uniform 

 washing, the small number of leaves available for analysis from green- 

 house tests, loss in ashing, etc.; nevertheless the results shown in Table 2 

 are helpful. 



Table 2. — Effect of Adhesives on Spray Residue. 



Fungicide and Adhesive 



Copper on Leaf Surface 

 PER 100 Square Inches 



Deposited 



After Washing 



Adherence 

 Observed 



after 

 Washing 



(Guha) 



Bordeaux mixture 4-4-50 



Basic copper sulfate (same concentration as 

 Bordeaux) : 



without adhesive 



with — sugar 0.10% 



wheat flour (patent) 0.10% 



Tekoe flour 0.10% 



Tekoe flour 0.21% 



gum arable 0.10% 



saponin 0.10% 



glue 0.10% 



Laucksite 0.10% 



skim milk powder 0.10% 



semi-solid buttermilk. . . .0.10% 



calcium caseirate 0.10% 



Castile soap 0.10%, 



rosin fish-oil soap 0.10% 



Wilkinite 0.10% 



A verage 



Crams 

 0.0094 



0.0091 

 0.0098 

 0.0113 



0.0028* 



0.0077 

 0.0105 



0.0071 

 0.0092 

 0.0067 

 0.0099 

 0.0091 



Crams 

 0.0068* 



0.0045* 



0.0030 



0.00.56 



0.0042 



0.0046 



0.0040 



0.0010 



0.0037 



0.0056 



0.0013 



0.0026 



0.0028 



0.0050 



0.0032 



0.0029 



0.0035 



excellent 



poor to fair 



poor 



good 



fair to good 



fair to good 



poor to fair 



poor 



fair to good 



poor 



fair to good 



fair 



*Excluded from average. 



