PICKERING SPRAYS. 45 
dicating that these sprays exerted similar stimulating and protec- 
tive action on potato plants. 
The adhesive properties of Pickering sprays varied with the 
foliage to which they were applied. They adhered to potato and 
cranberry leaves in practically the same degree as the standard 
Bordeaux, to apple leaves in a somewhat higher proportion, and to 
grape leaves in a lower proportion. 
No injurious effects followed the application of Pickering sprays 
to potatoes in Maine or to cranberries in New Jersey. The sprays, 
however, proved to be too caustic for use on the apple in Virginia or 
on grapes in New Jersey and Virginia. Pickering sprays can not be 
used on tender foliage. 
Barium-water sprays of the Pickering type, made with barium 
hydrate instead of lime and containing 0.7 per cent of copper sul- 
phate, proved very successful as a fungicide for potatoes. Such a 
spray containing 0.6 per cent of copper sulphate did not injure the 
foliage or fruit of the apple tree. 
These results are presented as the basis for further studies to be 
conducted in various parts of the country. It is believed that from 
this material agricultural experiment stations and other agencies 
will be able to devise formulas for sprays for certain crops contain- 
ing less copper sulphate than standard Bordeaux, which will prove 
just as effective as the more expensive spray. 
