BEOWN-ROT OF PEUNES AND CHERRIES. 5 



time the number of fruit spurs that had borne blossoms and the 

 number of prunes still remaining were counted on representative 

 branches from the various plats. The results obtained are shown in 

 Table I. 



Table I. — Prune spraying experiments at Felida, Wash., in March and April. 1915. 



Plat. 



Sprayings. 



Prunes per 

 4,000 spurs. 



Plat. 



Sprayings. 



Prunes per 

 4,000 spurs. 



No.2 



No. 3 



First, second, and third. . 



First and second 



Second 



292 

 243 

 369 



No. 9 



No. 10 



No. 6 



First and third 



None 



143 

 69 



No. 7 



do 



86 













These results show that the sprayed trees had retained from two 

 to five times as much of their fruit as the unsprayed ones. A com- 

 parison of the set of fruit on the different sprayed plats would indicate 

 that the second spraying was the most important onC; but that the 

 third was also very valuable. A study of the final crop from the 

 orchard, as given later, shows that the average yield on the nine 

 plats that received an application of self-boiled lime-sulphur, either 

 in the second or third spraying or both, was more than two and a 

 half times as great as that from plats 8, 10, and 11, which received 

 no early spraying. 



If an adhesive had been added to the fungicide in the second 

 application, there is little doubt that the results would have been 

 much more striking, for, as already mentioned, much of this spray 

 had been washed off by rains before the third application was made, 

 thus leaving but poor protection during the most critical period of 

 infection. 



The above data show very conclusively that the blossom blight 

 was an important factor in the poor set of fruit obtained in 1915. 

 Observations on the calyx browning and on the fruit drop m several 

 different sections of southwestern Washington and also in the orchards 

 near Salem, Oreg., indicated that the conditions described for Van- 

 couver were of general occurrence in the prune orchards of the lower 

 Columbia and Wdlamette Valleys. 



FRUIT ROT OF PRUNES. 



The orchard observations were continued throughout the summer, 

 and records were kept of weather conditions and the prevalence of 

 disease. Frequent showers occurred during the last three weeks 

 of May, but the weather during the latter part of the summer was 

 comparatively dry, the rainfall being considerably below the average 

 for the season. 



The occurrence of brown-rot was noted on some of the plats in 

 the latter part of May, but there was no serious outbreak at any 

 time during the summer. 



