20 THE CONTROL OF APPLE BTTTER-ROT. 



untreated trees used as checks. By referring to the plat of the 

 block (%. 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 onl}' 

 the three earl^- 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 originalh' set aside as 

 checks, but when it was found that bitter-rot was developing abun- 

 dantly on all of them some Avere sprayed in order to reduce the loss to 

 the owner. Two trees to the plot might seem at first thought insuflS- 

 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 onl}^ 

 one application in adjacent plots. 



W^EATHER CONDITIONS ATTENDING THE EXPERIMENT. 



Better conditions for a severe test of sprajing could scarcely be 

 desired. As will be seen from the following weather table ", there 

 was an abundance of rain throughout the season and considerable high 

 temperature. Beginning June 1() it rained ever}" day except one until 

 June 25, and during that period tlie 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° 'F. 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 daj" during the first 

 week and continued at intervals throughout the month. The tempera- 

 ture reached 91° 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. As a 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 unspra3''ed 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. 



