& 
20 THE CONTROL OF APPLE BITTER-ROT. 
untreated trees used as checks. By referring to the plat of the 
block (fig. 1) it will be seen that the checks (A, B, C, D, and E) 
were well scattered among the sprayed trees. Plot 1, at the lower 
left-hand corner, practically amounted to a check, as it received only 
the three early applications, and 62 percent of the crop rotted. Check 
A is near the lower right-hand corner and B just below the center, 
while C and D are near the upper. left-hand corner and E at the 
upper right-hand corner. Other trees were originally set aside as . 
checks, but when it was found that bitter-rot was developing abun- 
dantly on all of them some were sprayed in order to reduce the loss to 
the owner. ‘Two trees to the plot might seem at first thought insuffi- 
cient for determining the best results from the spraying, but the trees 
are quite large, yielding about 20 to 35 bushels each. Moreover, the 
plots are almost in duplicate, there being a difference usually of only 
one application in adjacent plots. 
WEATHER CONDITIONS ATTENDING THE EXPERIMENT. 
Better conditions for a severe test of spraying could scarcely be 
desired. As will be seen from the following weather table “, there 
was anabundance of rain throughout the season and considerable high 
temperature. Beginning June 16 it rained every day except one until 
June 25, and during that period the temperature ranged high, reach- 
ing 89° F. on the 18th, 94° F. on the 19th, 90° F. on the 20th, 89° F-. 
on the 21st, and 92°‘. on the 22d. This combination of moisture 
and heat made an ideal infection period. The conditions during July 
were also favorable to bitter-rot. It rained every day during the first 
week and continued at intervals throughout the month. The tempera- 
ture reached 94° F. on July 18, and was 92° F. on the preceding and 
the following day. The orchard was frequently enveloped in fog and 
the dews were usually very heavy. Asa consequence all unsprayed 
trees showed bitter-rot early in the month, and by the end of the 
month the disease was well under way. ‘This ideal bitter-rot weather 
continued through August, and before the end of that month the 
crop on all unsprayed trees was practically destroyed. The crops in 
the unsprayed orchards in the neighborhood were also badly affected, 
showing that the outbreak of bitter-rot was general in that region. 
«No exact meteorological data being available for the immediate vicinity in which 
the experiments were conducted, data are given for Charlottesville, Va., the nearest 
point where permanent records are kept, a distance of about 25 miles from the site 
of the orchard used for the experiment. The weather conditions appeared to be 
similar in the two sections, and the table may be considered fairly representative of 
the conditions that prevailed in the orchard. The data are from the monthly 
reports of the Virginia Section of the Climate and Crop Service of the Weather 
Bureau. ; 
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