10 CIRCULAR 867, U. S. DEPARTMENT OF AGRICULTURE 



adverse weather conditions, which may prevail during the bloom 

 period. They are also fairly resistant to the action of Elgetol sprays, 

 and if in good vigor there is little likelihood that overthinning will 

 result. On heavily blooming trees under Eastern conditions. 20 to 30 

 fruits per 100 blossoming spurs constitute a commercial crop. The 

 most satisfactory number varies somewhat with the variety, its season 

 of maturity, and orchard conditions. With reasonably good bloom 

 weather, trees of the above varieties receiving good care may set 50 

 to 60 fruits per 100 blossoming spurs. 



Whether or not such varieties as Jonathan. York Imperial, Rome 

 Beauty, and Grimes Golden can be safely sprayed in East and Mid- 

 west fruit sections will depend largely upon tree vigor and weather 

 conditions prevailing during the bloom period. In these fruit areas 

 such wholly self -unfruitful varieties as Mcintosh, Delicious, Northern 

 Spy. Winesap, and Stayman are generally not considered adapted 

 for chemical thinning with dinitro sprays. Fruit set on these varieties 

 in East and Midwest fruit areas is frequently unpredictable, and even 

 though a heavy set is expected to occur Elgetol may overthin. par- 



Table 4. — Comparison of effectiveness of 1 and 2 application* of 

 Elgetol thinning spray* applied to certain varieties of apples in 

 certain areas 



Yarietv 



Wealthv 



Do. 



Do. 



Golden 

 Delicious. 



Do___. 



Do. 



Jonathan. 



Do. 



I) 



Concen- 

 tration 



of 

 Elgetol 

 per 100 

 gallons 



Pints 











1.6 



1:6 







1.6 



1.6 







2.0 



2.0 







2.0 



2.0 







2.0 



2.0 







1.3 



1.3 







2.0 



2.0 







2.0 



2.0 



Date sprayed 



Mav 27 



May 27: Mav 29 



Mav 1 



April 20; May 1 



Mav 11 



Mav 11: Mav 14 



April 26 



April 26: April 29 



Mav 3 



Mav 1 : Mav 3 



May 17 



Mav 15: Mav 17 



May 



MaV 



1 



l:Mav 3 



April 21 



April 20: April 21 



Mav 12 



MaV 11: Mav 14 



Year 



1940 

 1940 

 1940 

 1941 

 1941 

 1941 



: 1941 

 1941 

 1941 



| 1946 

 1946 

 1946 

 1946 

 1946 

 1946 

 1948 



\ 1948 



! 1948 

 1946 

 1946 

 1946 

 1947 

 1947 

 1947 

 1948 

 1948 

 1948 



Full bloom 



Percent 



65 



65: 100 



100 

 75; 100 



100 

 75: 100 



75 



75: 100 



100 

 75; 100 



75 



75: 100 



o 



75: 100 



100 

 65; 100 



Fruits 

 per 100 



blos- 

 soming 



spurs 



75 



75: 100 



umber 



45 



15 

 5 

 47 

 27 

 22 

 52 

 42 

 13 

 100 

 83 

 77 

 99 

 71 

 57 

 97 

 35 

 16 

 97 

 96 

 63 

 95 

 82 

 79 

 67 

 34 

 10 



Reduc- 

 tion 



fruit 

 set 



Percent 



67 

 89 



43 

 53 



19 

 75 



17 

 23 



28 

 42 



64 

 84 



1 

 34 



49 

 85 



State and 

 literature 

 reference 



New York 

 (29). 



New York 

 20 . 



Do. 



Washing- 

 ton (5). 



Do. 



Washing- 

 ton. 



Do. 

 Do. 

 Do 



