FRUIT THINNING WITH CHEMICAL SPRAYS 7 



pointed out above, spray applications as late as 1 to 3 days (normal 

 weather) following full bloom have been (under many conditions) as 

 effective or only slightly less effective than applications at the full- 

 bloom stage. Timing, therefore, is not too critical and allows from 1 

 to 3 days under most conditions to make applications. This is a 

 sufficient period for most growers to spray a sizable block of a given 

 variety. 



Concentration 



Since the effective concentration of Elgetol is related to weather 

 conditions, tree vigor, variety, and possibly other factors, no inflexible 

 recommendation is possible. The relationship of these factors to 

 results obtained will be discussed later. The effective concentration of 

 Elgetol for thinning apples will generally vary from 1 pint to 1 quart 

 per 100 gallons. Spray solutions with concentrations much greater 

 than 1 quart per 100 gallons may result in foliage and spur injury 



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

 ning sprays when applied during the bloo?n period on certain 

 varieties of apples, 19%2-If6 



Variety 



Northwestern Greening 



Cortland 



Delicious 



Mcintosh 



Wealthy 



Baldwin 



Rome Beauty 



Yellow Transparent 



Early Mcintosh 



Yellow Transparent 



Year 



1942 

 1942 

 1942 

 1942 

 1942 

 1942 

 1942 

 1942 

 1943 

 1943 



Concen- 

 tration 



of 

 Elgetol 

 per 100 

 gallons 



Pints 







1.0 

 2.0 

 



1 



2 







1 



2 







1 



2 







1.0 



2.0 







1 



2 







1 



2 







1 



2 







1 



2 







1.2 



1.7 



Fruits 

 per 100 



blos- 

 soming 



spurs 



Number 



38 

 11 

 1 

 34 

 7 

 2 

 35 

 8 

 

 98 

 76 

 32 

 74 

 45 

 43 

 72 

 51 

 32 

 57 

 35 

 15 

 64 

 22 

 13 

 66 

 40 

 17 

 56 

 34 

 30 



Reduc- 

 tion 



fruit 

 set 



Percent 



71 



97 



79 

 94 



77 

 100 



22 



67 



39 

 42 



29 

 55 



38 

 74 



66 



80 



39 

 74 



39 

 46 



State and 

 literature 

 reference 



New York {24). 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 

 West Virginia {3) . 

 New York {25). 

 •West Virginia {4). 



