20 
The comparative efficacy of copper carbonate, sulphur powder, and Mixture No. 5 in 
preventing Apple Scab. —This will appear by consulting Fig. 1 ancl PI. iv, Fig. 5. In the 
experiment the trees were sprayed six times with the sulphur powder and eight times 
with the Mixture No. 5. We therefore compare those treated with the former with 
the trees sprayed six times with the ammoniacal copper carbonate, and those treated 
with the latter with those sprayed eight times with the ammoniacal copper carbon¬ 
ate. In Fig. 4, PL iv, is shown the proportion of fruits in each of the three qualities 
from the trees sprayed eight times with the Mixture No. 5, and the copper carbon¬ 
ate as compared with those from the untreated trees. 
The white portion represents the first quality, the diagonal lines the second, and 
the black portion the third quality. 
From this it appears that the Mixture No. 5 was considerably the more efficacious. 
In Fig. 5 we compare the effect of six treatments with the sulphur powder and ammo¬ 
niacal copper carbonate with that of the check trees, from which it would seem that 
the sulphur powder actually appeared to increase the amount of scab. It is more 
probable, however, that the trees treated with this material were from some cause 
more than usually affected with the disease which the sulphur compound, possibly 
owing to its ready solubility which caused it to be easily washed off by the rains, en¬ 
tirely failed to prevent. 
The efficacy of copper carbonate suspended in water as compared with that dissolved in 
ammonia. —From Fig. 6 it is evident that the results from six sprayings of copper 
carbonate applied in suspension and in ammoniacal solution were very meager in 
both cases. The first and third qualities were larger in the case of the solution, while 
the second was larger in that of the suspendel copper carbonate. If the results may¬ 
be assumed to teach anything it would seem that there was little difference in the 
efficacy of the two methods of application. 
From Fig. 8, in which the data represent the results of spraying the Canada peach 
apple with suspended copper carbonate before and after bloom, the benefit from the 
treatment before bloom is very perceptible, which indicates that this method of using 
copper carbonate is capable of giving good results. 
The value of treatment previous to the opening of the flowers. —From Fig. 7 it is evident 
that one treatment of the Fameuse apple before the flower had opened with three 
treatments after the petals had fallen was much more efficacious in preventing the 
scab than four treatments made after the falling of the petals, a result which is cor¬ 
roborated in Fig. 8, which represents the results secured in treating two trees of the 
Canada Peach twice before bloom and twice after, as compared -with four treatments 
after bloom. 
The number of treatments necessary to secure the most beneficial results. —From Fig. 9 it 
appears that eight treatments gave only slightly better results than four, but that 
four gave considerably better than two. The first two treatments succeeding the 
falling of the petals (made May 31 and June 16), it would appear, gave absolutely no 
results, while the two made June 28 and July 14 seem to have proved beneficial. 
The excessive rains during the early part of June doubtless washed off the fungi¬ 
cides from the foliage before they had time to act, and at the same time promoted the 
growth of the fungus. The lesson suggested is that treatments made after midsum¬ 
mer are of doubtful value. 
To ivliat extent does the scab reduce the size of the fruit f —As will appear from the table 
on a preceding page all of the fruits of the Fameuse apple in the different qualities 
were weighed. These weights furnish data from which we may compute with a fair 
degree of accuracy the influence of the scab in reducing the size of the apples. As 
only the scab was considered in assorting, we are perhaps justified in assuming that 
the reduced size of the scabby fruits was due to the exhaustive action of the fungus, 
and that had all the apples been free from the disease all would have been as large 
as those of the first quality. From the data it appears that, averaging the crop from 
all of the Fameuse trees, the fruits of the first quality weighed 262 ounces per hun- 
