PICKERING SPRAYS. 39 



before full bloom), June 25 (10 days after full bloom), July 24, and 

 August 12. The small plats were separated by four-foot paths over 

 which the spray apparatus was drawn, thus protecting the berries 

 on the sprayed plats from injury like that received in 1917. The 

 vines on plats 5 and 6 were heavier than those on the other plats. 

 Pickering (A) and (C) sprays, a barium-water spray, two sal-soda 

 (Na 2 C0 3 ) sprays, and three sprays of the Bordeaux type, made with 1 

 per cent of copper sulphate and varying amounts of lime, were em- 

 ployed (Table 12). The sal-soda (Na 2 C0 3 ) and fish-oil-emulsion 

 spray was prepared by shaking together 1 ounce of water and an 

 equal amount of fish oil until emulsified, and then stirring it into the 

 spray. The barium-water spray was prepared by the use of barium 

 hydrate in place of lime (p. 16). The Pickering (C) spray was made 

 with an excess of limewater, and the Pickering (A) spray with just 

 the amount of limewater required to neutralize all the copper sul- 

 phate present (p. 3). 



^.As shown by the figures for rotten berries, 15.1 and 69.7 per cent 

 for the check plats (Nos. 3 and 7), the amount of rot varied greatly. 

 The lowest percentage of rotten berries was obtained on plat 2, 

 where sal-soda and fish-oil-emulsion spray was used. 



The following notes were taken on September 5: 



Plat. 1. — The sal-soda spray resembles the Bordeaux, 4-3-50, spray 

 used on plat 8. 



Plat 2. — The berries look sound. More spray is seen on berries 

 than on those in plat 1. It occurs in isolated spots or freckles 

 rather than in a continuous layer, as is the case with the spray on 

 plat 1. 



Plat 3. — Berries are quite sound. Not over 5 per cent of rot is 

 visible. 



Plat 4- — Spray is seen distinctly over entire plat. It is the only 

 plat that looks blue at a distance. Good protection is afforded, 

 although there is more rot than on plats 1 and 2. The spray shows 

 regularly on the berries, but is not of uniform density. The berries 

 with spray have a festooned appearance, a,s if each drop of spray on 

 drying was thickest at the periphery. 



Plat 5. — But few rotten berries seen. Spray shows plainly in 

 spots. 



Plat #.— Same as plat 5. 



Plat 7. — Estimated 50 per cent rot. 



Plat 8. — Berries very sound. A little more spray visible than on 

 either plat 5 or 6. 



Plat 9. — Generally like plat 8. Spray somewhat more apparent. 

 Vines not quite as thick as on most of the other plats. 



Plat 10. — Spray shows about like that on plat 9. The northern 

 end of the plat is poor land and shows more rot. Rest of plat is very 

 sound. 



