10 



MASS. EXPERIMENT STATION BULLETIN 381 



Marth, and Batjer (2) in tlieir first full rei)ort in 1939 stated that with 

 Mcintosh ". . . . as with other varieties, the higher concentrations have 

 given better control within the effective period." Some further work 

 (1940) by Batjer and Marth (1) supports this statement, especially in re- 

 gard to late varieties. However, with some varieties, particularly Williams 

 Early Red (1) and Mcintosh', drop control was not necessarily improved 

 by increasing the hormone concentration above 5 p. p.m. Also, Murphy (5) 

 in Rhode Island found no significant differences in the drop of Mcintosh 

 from trees receiving sprays with different hormone concentration. Consid- 

 erable variability was evident within treatments. The results of Hoffman 

 (3) in New York with Mcintosh suggest that the standard .001 percent 

 sprays were possibly a little more reliable than sprays with half the amount 

 of hormone. Murneek (4) found more reduction in amount of dropping 

 of Delicious with a .001 than with a .0005 percent spra\'. Other experi- 

 ments seem to present a further picture of variability in results. However, 

 the evidence on the whole seems to verifj' the authors' experience that the 

 higher concentrations up to 10 p. p.m. are usually somewhat more effective 

 in controlling preharvest drop. A test (Mcintosh) in Canada^ resulted 

 in better control with about 15 p. p.m. of hormone than with the standard 

 10 p. p.m. spray. In a single test with Baldwin at Amherst, a sim- 

 ilar high concentration seemed to increase effectiveness. But most of the 

 sprays contained 10 p. p.m. or less of actual hormone. Table 4 gives some 

 results with Mcintosh and Wealthy. 



Table 4. — Percentage of Total Crop That Dropped After Treatments 

 Became Efft:ctive in Several Tests. 



'L. P. Batjer. Correspondence. 1941. 

 ^G. H. Dickson. Correspondence. 1940. 



