Jan. 21. 191S Irrigation Experiments on Apple-Spot Diseases 



125 



The relative susceptibility to bitter-pit of the apples from the dif- 

 ferent plats was the same as in previous experiments, the fruit from 

 the trees receiving heavy irrigation late in the season having the largest 

 amount of disease, that from those heavily irrigated throughout the 

 season the next, and that from those receiving heavy irrigation followed 

 by light having the least (fig. 10). As was found in the experiments 

 of 1 91 5, the apples from the early picking showed much greater sus- 

 ceptibility to bitter-pit than those of the late picking. 



The size of the apples from the various plats and the relative suscep- 

 tibility of the different sizes to bitter-pit is shown in Table IX. 



P£Q CENT OF B/Tr5P'PfT 



3 4 S 



77t 



P£P CENT OF BiTTER-PtT D£V£LOPeD BY NOV. I-*. 



c 



J pea CENT OF BITTER-PIT DEVELOPED BETWEEN NOV 14. AND MARCH IB. 



Fig. 10. — Diagram showing the amount of bitter-pit on Jonathan apples in 1916. The black portions of 

 the bars indicate the percentage of apples affected with bitter-pit on November 14 and the white portions 

 the percentage developed between November 14 and March 18. See figure 9 for scil-moisture conditions. 



Table IX. — Percentage, according to size, of Jonathan apples affected with bitter-pit. 



March 18, igi6 



The plats receiving heavy irrigation late in the season had more 

 large apples than the others. The amount of bitter-pit on the fruit of 



