Obviously, scoring is not as effective a treatment as substantial chem- 

 ical thinning for inducing annual flowering of mature Early Mcintosh 

 trees. However, it may occasionally improve the ajnount of "return" 

 bloom obtained if used as a supplement to chemical thinning. 



Table 1. The influence of chemical thinning and scoring on fruit set, 

 size and return bloom of Early Mcintosh apples. 1963-614. 



196L|^ 



3. Sevin-3#(50% W.P.) 6 . 9d 2.t+ld 7.7b 15.1c 



NAA-20 ppm. 



4. Sevin-3#(50% W.P.) 15.9b 2.22b 0.1a 0.2a 



Sevin-3#(50% W.P.) 



5. NAD-50 ppm. 7.2cd 2.46cd 12.6c 13.1c 



NAA-20 ppm. 



Applied at petal-fall and 10 days after petal-fall, respectively. Six 

 trees per treatment. 



2 



Fruit size measurements made August 6, 1963 (60 fruits at random per 



tree) about 2 weeks before harvest commenced. 



3 

 All but one major limb per tree scored 3 times on June 13, 1963. 



li 

 Means followed by different letters are significantly different at the 



5% level. 



The question of whether or not a moderate or heavy "return" bloom 

 should be chemically thinned is frequently asked. Until now, we've had 

 very limited data on the subject, but it was our general observation 

 that good "return" blooms on heavy-setting varieties like Early Mclntojsh 

 usually require a continued chemical thinning treatment, otherwise over- 

 setting and biennial bearing recur. Also, it has been observed that 

 chemical thinners may be less effective in reducing fruit set on "return' 

 blooming trees than they are on biennial trees in their "on" year. 

 Table 2 provides some information on this subject. 



