PLAN OF EXPERIMENT. | 19 
THE PLAN OF THE EXPERIMENT. 
Object.—This experiment was designed to determine (1) to what 
extent bitter-rot could be controlled by spraying with Bordeaux mix- 
ture, (2) the number of applications required, and (3) the proper time 
to make these applications. Owing to the influence of weather condi- 
tions upon this disease it was not expected that answers to all these 
questions could be obtained in a single season; but the season of 1905 
was so favorable to bitter-rot, the disease appearing so early and con- 
tinuing with such force throughout the season, that the results obtained 
are believed to be a safe guide for almost any season. 
Spraying scheme.—In order to solve the questions just enumerated 
it was necessary to cover the entire season with a varying number of 
applications, using a process of elimination in the plan. as shown in 
Table II (p. 23). As may be seen by reference to this table, the dates 
of the successive applications were as follows: April 8, May 1, May 9, 
June 12, June 27, July 10, July 25, August 7, August 22, and September 
4. The first date was just after the cluster buds had opened, exposing 
the blossom buds, but before the latter had opened; the second just 
after the petals had fallen, and the third application eight days later. 
The fourth date was about six weeks after the petals had fallen, the 
subsequent dates being at intervals of about two weeks. The object 
of the first three applications was to combine the treatment of apple 
scab with that of bitter-rot and to determine their effect upon the latter. 
As shown in Table II, one group of plots (Nos. 1 to 5) receiving three 
to nine applications had one or more of the late sprayings omitted. 
From another group (Plots 9 to 12) the early applications for scab were 
omitted. Plots 15,16, 17, and 12, receiving four applications each, were 
designed to determine the period at which spraying gives the best 
results. Plots Tand 8 combine early and late spraying, leaving an early 
midseason interval that proved in this case to be too long. Plot 6 was 
sprayed just before the trees bloomed, as soon as the blossoms were 
shed, and eight days later (the usual apple-scab treatment), and every 
two weeks from June 12 to September 4, receiving ten applications in 
all. It was intended that Plot 9 should be sprayed at intervals of two 
weeks, beginning June 12, making the treatment for this plot the same 
as No. 6, with the three early applications omitted; but the writer inad- 
vertently overlooked the first date. Therefore, in order to avoid dupli- 
cating No. 10, two more applications were dropped out of No. 9 later 
in the season. The original scheme included Plots 13 and 14, which 
were to have received the last three and the last two applications, 
respectively; but when the time arrived for their treatment to begin 
the crop on them was already destroyed by the rot and they were 
therefore dropped. 
Each plot consisted of but two trees. There were, then, in the 
experimental block fifteen treated plots of two trees each and five 
oe 
