18 



STATION BULLETIN 355 



Table 13. Effect of Spraying with Borax and of Thinning on Per Cent 



of Red Color in Mcintosh 



color of fruit and drops showed that on the same date the coefficient 

 of correlation between color of fruit of different trees and percentage 

 drops was — ^.027. Ten days before harvest date the dropped fruit 

 possessed as much red color as fruit harvested from the tree. Dropped 

 fruit from trees sprayed with borax possessed 10 per cent more color 

 on the date of harvest than that from unsprayed trees, while fruit 

 picked from the sprayed trees averaged 15 per cent more color than 

 that picked from control trees (Table 13). The results, however, were 

 not statistically significant, the average differences being due to the 

 wide differences in color of fruit of a few individual trees. 



HORMONE SPRAYS 



Following the annoimcement by Gardner ct. «/.*' that dropping of 

 the apple could be lessened or possibly prevented with growth- 

 promoting substances, some apple varieties in the block designated 

 as "26" were sprayed in 1940 with ^ to 1 part per 100,000 naphthalene- 

 acetic acid just as dropping commenced in the fall. The early va- 

 rieties Melba, Early Alclntosh, Gravenstein, and Milton definitely 

 benefitted from the treatment. In fact, Melba fruit remained attached 

 to the spurs until the flesh became so soft that it finally separated 

 from the cores, leaving the latter attached to the tree indefinitely. On 

 the other hand, fruit dropping of Cortland, Mcintosh, and Spy was 

 not retarded as a result of the treatment. 



Since the air temperature was higher when the early varieties 

 were sprayed, the failure of the hormone spray with late varieties was 

 attributed to lower temperature at the time of spraying. In 1941, 

 therefore, Mcintosh trees in the BF block were sprayed with a com- 

 mercial 'set' at the strength recommended by the manufacturer. Two 

 rows were sprayed with the hormone in cold water, two rows with 

 the hormone in warm water and two rows were left as a control. The 

 results are presented in Table 14. Although application of the hor- 

 mone in warm water had apparently reduced the pre-harvest drop 

 while that in cold water had not, the differences were not large. Fur- 

 thermore, the same trees showed significant differences in drop in 

 previous years when none was sprayed with hormones. This leads 



