8 CIRCULAR 867, U. S. DEPARTMENT OF AGRICULTURE 



Table 3. — Effectiveness of different concentrations of Elgetol thin- 

 ning sprays when applied during the bloom period on certain 

 varieties of apples, Wlfe-ifi — Continued 



Variety 



Grimes Golden, _ 

 Golden Delicious 



York Imperial- _ 



Golden Delicious 



Winesap 



Do___ 



Delicious 



Do. _______ 



Do 



Jonathan 



Year 



1944 

 1944 



1944 



1945 

 1945 



1946 

 1946 

 1947 

 1948 

 1946 



Concen- 

 tration 



of 

 Elgetol 

 per 100 

 gallons 



Pints 







.8 

 1.2 

 



1.0 

 1.5 

 



.8 

 1.2 

 1.6 

 2.0 

 2.4 

 



1.5 

 2.0 

 



.7 

 1.4 

 



.7 

 1.4 

 



.7 

 1.4 

 



1.0 

 2.0 

 



1.0 

 2.0 

 ' 

 1.3 

 2.0 



Fruits 



per 100 



bios- 



Reduc- 

 tion 

 in 



soming fruit 

 spurs set 



Number 



49 



29 

 24 

 54 

 34 

 29 

 89 

 47 

 27 

 27 

 27 

 20 

 107 

 81 

 83 

 58 

 42 

 41 

 96 

 84 

 73 

 61 

 61 

 55 

 66 

 50 

 53 

 60 

 29 

 18 

 97 

 96 

 78 



Percent 



41 

 51 



37 

 46 



47 

 70 



70 

 70 



77 



24 

 22 



28 

 29 



13 

 24 



24 

 20 



52 

 70 



State and 

 literature 

 reference 



Do. 

 West Virginia (4) 



Virginia (11). 



Washington (-5). 



Do. 



Do. 



Do. 



Do. 

 Washington . 



Do. 



under some conditions, whereas amounts much less than 1 pint in 

 most cases will not result in sufficient thinning. 



Comparative effectiveness of different concentrations of Elgetol 

 sprays is presented in table 3. Eeduction in set is usually greater with 

 the stronger spray, but there are numerous exceptions. Under New 

 York conditions, apparently a more direct relationship between con- 

 centration and reduction in fruit set is obtained than under conditions 

 prevailing in Washington. Eepeated observations in Washington 

 indicate that an increase in concentration will frequently result in 

 significantly greater thinning under conditions unfavorable for fruit 

 set. 



When cool, humid weather prevails during the bloom period it is 

 believed that a greater amount of thinning of the indirect type 

 results from the stronger sprays. Under Northwest conditions if the 

 bloom period is characterized by rather warm weather with low 



