22 THE CONTROL OF APPLE BITTER-ROT. 



counted without climbing the trees, which probably means an infec- 

 tion of 10 to 15 per cent of the crop, since there must have been many 

 diseased fruits unseen. 



Plot 1 showed about 21 diseased fruits on each tree. 



Plot 2 showed 5 diseased fruits on one tree and 6 on the other. 



Plots 3, 4, and 5 showed 1 to 3 diseased fruits on each tree. 



Plot 6 showed no rot. 



Plots 7 and 8 showed 9 to 30 diseased fruits on each tree. 



Plots 9 and 10 showed 7 to 18 diseased fruits on each tree. 



Plot 11 showed 22 diseased fruits on one and 36 on the other tree. 



Plot 12, which had not been sprayed, showed 112 diseased fruits on 

 one and 150 on the other tree. 



Plot. 15 showed 25 affected fruits on one tree and 35 on the other. 



Plot 16 showed 6 affected fruits on one tree and 10 on the other. 



Plot 17 was apparently still free from bitter-rot. 



The above is sufficient to indicate that in practically every tree there 

 was an abundant supply of spores for a serious outbreak of the disease, 

 and that wherever Bordeaux mixture was lacking the fungus became 

 rampant. 



It was almost impossible with the equipment used to spray the tops 

 of most of the trees thoroughly, and later examinations showed that 

 some bitter-rot occurred in the top of every tree. Every rain must 

 have washed down an abundance of spores from diseased apples in the 

 tops to fruits below. 



In Table II the results from the two trees in each plot are combined, 

 and the windfalls, both rotten and sound, are included. As a rule, 

 half to three-fourths of the rotten fruit was on the ground at picking 

 time. This was true of sprayed as well as unsprayed trees. 



The crop of the experimental block was picked and sorted on Sep- 

 tember 19 to 23, inclusive, and the result from each tree kept separate. 

 The fruit on the ground was picked up and classified into sound and 

 rotten, and the fruit picked from the tree was likewise classified. 

 Sound fruit constituted every apple free from bitter-rot, regardless of 

 codling moth or scab. All fruits that were unmistakably affected with 

 other rots, such as Sphaeropsis, Penicillium, and Monilia, were dis- 

 carded and not included in either class. As a rule, this did not exceed 

 3 per cent of the crop. Wherever there was any doubt, however, the 

 trouble was charged to bitter- rot. 



The final results of these experiments are shown in Table II, and it 

 will be seen from this table that in every treated plot Bordeaux mixture 

 had a beneficial effect regardless of the time of application, and that 

 where the trees were properly sprayed the loss was less than 5 per cent 

 of the crop, while the untreated trees suffered a total loss. It is rare 

 that such results are obtained in the treatment of a plant disease. 

 With the exception of leaf -curl of the peach, leaf -blight of the pear, 



