35 
SODA HYPOSULPHITE CONTRASTED WITH POTASSIUM SULPHIDE AND 
CALCIUM SULPHIDE FOR THE APPLE SCAB. 
Iii former reports are given the results of experiments with soda hypo¬ 
sulphite for the apple scab, Fusicladium dendriticum , Fckl. From these 
it appears conclusively that this substance as used acted beueficially, 
but that it was not a complete remedy for this disease. It is very de¬ 
sirable that some substance be found that will prove more effectual in 
destroying* this fungus without causing greater harm to the foliage. 
Two other compounds of sulphur, viz, potassium sulphide and calcium 
sulphide, were therefore tested the past season. The first trial was 
made with the potassium sulphide in solution, at the rate of half an 
ounce to the gallon, upon the crab-apple tree treated for three seasons 
preceding with soda hyposulphite, as described in the experiments 
cited. 
The spraying, which was done with the so-called Little Gem force- 
pump, fitted with a u Climax v nozzle, was made upon the west half of 
the tree only, and was commenced May 10, just as the leaves were ex¬ 
panding, and repeated after every hard rain until July 24, eight appli¬ 
cations having been made in all. 
The tree blossomed alike, apparently, on both the sprayed and un¬ 
sprayed portions, but the crop of fruit matured was much larger on the 
sprayed part, and, as the following figures will show, was of much bet¬ 
ter quality. 
On September 12 a quantity of fruit was picked from the sprayed and 
from the unsprayed parts of the tree, and each lot assorted into three 
classes, in order to determine their relative injury from the disease. In 
the first quality were put only fruits nearly or quite free from scab; in 
the second those that were considerably scabby, but not so much as to 
distort their form or prevent them from acquiring their normal size, 
and in the third those which were distorted in form or diminished in 
size by the growth of the fungus.* The results secured as follows : 
-■ 
Number 
of fruits 
examined. 
Per cent, 
in first 
quality. 
Per cent, 
in second 
quality. 
Per cent, 
in third 
quality. 
Sprayed part.. 
1,560 
627 
75. 9 
22. 6 
1.5 
Dnsprayed part .... 
46.9 
45.3 
7.8 
More than G27 fruits did not mature on the unsprayed part of the 
tree. On the sprayed part, however, many more might have been gath- 
* This classification is necessarily somewhat arbitrary, but, as the assorting was 
done with care, it is believed that the figures represent the true proportions of the 
amount of injury wrought by the scab. Almost all the fruits were somewhat scabby 
in the cavity about the stem, but if not affected elsewhere, this did not exclude them 
from the first quality. 
