18 MASS. EXPERIMENT STATION BULLETIN 372 



ficance of high summer means, short periods of high temperatures late in the 

 season, and wet seasons in increasing drop. 



The use of hormone sprays to prevent drop at harvest has met with success in 

 some prehminary trials. Since this development is definitely in the experimental 

 stage, however, many details need careful investigation and checking. A sound 

 evaluation of the method should be forthcoming in the near future. 



References 



1. Brittain, W. H. Apple pollination studies in the Annapolis Valley, Nova 



Scotia, Canada, 1928-1932. Dom. Can. Dept. Agr. Bui. 162 (new series). 

 1933. 



2. Bryant, L. R. A study of the factors affecting the development of the 



embryo-sac and the embryo in the Mcintosh apple. N. H. Agr. Expt. 

 Sta. Tech. Bui. 61. 1935. 



3. Detjen, L. R. Physiological dropping of fruits. Del. Agr. Expt. Sta. Bui. 



143. 1926. 



4. Dickson, G. H. Some factors affecting the dropping of Mcintosh apples. 



Sci. Agric. 19:712-721. 1939. 



5. Gardner, F. E., P. C. Marth, and L. P. Batjer. Spraying with plant growth 



substances to prevent apple fruit dropping. Science 90:208-209. 1939. 



6. Gardner, F. E. Control of the preharvest drop of apples by spraying with 



plant hormones. Proc. N. Y. State Hort. Soc. (85th Ann. Meeting): 

 94-105. 1940. 

 6a. Gardner, F. E., P. C. Marth, and L. P. Batjer. Prevention of the pre- 

 harvest drop of apples by spraying with plant growth substances. Proc. 

 Amer. Soc. Hort. Sci. 37. 1940. (In press.) 



7. Heinicke, A. J. Factors influencing the abscission of flowers and partially 



developed fruits of the apple (Pyrus malus L). N. Y. Agr. Expt. Sta. 

 Bui. 393. 1917. 



8. Heinicke, A. J. Concerning the shedding of flowers and fruits and other 



abscission phenomena in apples and pears. Proc. Amer. Soc. Hort. Sci. 

 16:76-83. 1920. 



9. Hodgson, R. W. Girdling to reduce fruit drop in the Hachiya persimmon. 



Proc. Amer. Soc. Hort. Sci. 36:405-412. 1939. 



10. Hoffman, M. B. Increasing the amount of red colour on apples after 



harvesting. Proc. Amer. Soc. Hort. Sci. 35:212-216. 1938. 



11. Hoffman, M. B. The preharvest drop of mature Mcintosh apples as in- 



fluenced by applications of nitrogen carrying fertilizers. Proc. Amer. 

 Soc. Hort. Sci. 37. 1940. (In press). 



12. Latimer, L. P. Further observation on factors affecting fruit setting of the 



Mcintosh apple in New Hampshire. Proc. Amer. Soc. Hort. Sci. 28:87-92. 

 1932. 



13. Latimer, L. P. Pollination and fruit setting in the apple. N. H. Agr. 



Expt. Sta. Bui. 274. 1933. 



14. MacDaniels, L. H. and A. J. Heinicke. Pollination and other factors affect- 



ing the set of fruit, with special reference to the apple. N. Y. Agr. Expt. 

 Sta. Bui. 497. 1929. 



15. MacDaniels, L. H. Some anatomical aspects of apple flower and fruit 



abscission. Proc. Amer. Soc. Hort. Sci. 34:122-192. 1937. 



