Jan. 21. 1918 Irrigation Experiments on Apple-Spot Diseases 



129 



Table XI. — Percentage of Jonathan apples affected with Jonathan-spot in igi6 



Plat 

 No. 



Irrigation treatment. 



Percentage of apples affected with Jonathan-spot. 



November 14. 



First 

 pick- 

 ing. 



Second 

 pick- 

 ing. 



Total. 



March 18. 



First 

 pick- 

 ing. 



Second 

 pick- 

 ing. 



Total 



for 

 year. 



Heavy 



Medium 



Light 



Medium, followed by heavy 



Heavy, followed by light 



Alternating, heavy, medium, heavy 



Alternating, heavy, medium, heavy, 



medium 



1-3 

 3-8 



0-3 

 o. o 

 0.0 



.6 

 o. o 



•4 



0.8 

 2. I 

 II. 8 

 3-0 

 •3 

 2. I 



55-8 

 51-2 

 72. 2 

 66.3 

 18. 2 

 53-3 



82.8 



16. 2 



33-9 



65-4 

 54- 2 

 66.5 

 69. I 

 24. o 

 64.7 



23.8 



Table XII. — Percentage, according to size, of Jonathan apples affected with Jonathan- 

 spot in igi6 



On November 14 the Jonathan-spot was worse on the apples of the 

 first picking than on those of the second, but by March 18 this condi- 

 tion had in most cases been reversed. There was little contrast be- 

 tween the amount of disease on the fruit of different sizes. The con- 

 trasts between the irrigation plats were not very consistent, but in 

 general indicated that heavy irrigation favored the disease. Plats 5 

 and 7, on which the fruit was lowest in color, had least of the disease. 



DISCUSSION OF RE;SULTS on JONATHAN-SPOT 



The experiments on Jonathan-spot have furnished little in the way 

 of consistent positive results. In both 191 5 and 1916 the apples of 

 the early picking had more of the disease than those of the late picking. 

 In 1 91 5 the large apples developed more Jonathan-spot than the small 

 ones, but this did not hold in 19 16. The results of both years gave 

 some evidence that heavy irrigation was more favorable to the disease 

 than light irrigation, but there was nothing to indicate that the amount 

 of soil moisture was an important factor in determining the amount 

 of Jonathan-spot. 



