-7- 



RESULTS FROM THE McINTOSH PREHARVEST DROP CONTROL EXPERIME^^^ 



This fall comparative testing of 2,4,5-TA and NAA was carried out for the 

 fourth consecutive year in a heavily bearing block. (45 box average per tree) of 

 Mcintosh at Bolton. In addition to comparing 2,4,5-TA with two applications of 

 NAA (our commercial reconmendation) mixtures of NAA and 2,4,5-TA were tried. We 

 have known that when 2,4,5-TA is effective that it may require a week or more 

 before it shows any benefit. Therefore, if some quick acting material like NAA 

 is added to 2,4,5-TA it might be possible to obtain good drop control for at 

 least 3 weeks with a single spray application and still have a minimum amount 

 of fruit ripening. 



In Figure 1 are shown the major findings from this experiment. 



50 ^ 



40 .. 



a 

 o 



<^ 



4) 



> 



30 .. 



^ 20 



Mcintosh Drop 

 1958 

 7 Trees per Treatment 



Check 



2,4,5-TA - 20ppra - 9/11 



^ NAA - 20ppm-9/ll ih MAA - 20ppm - 9/24 

 4 NAA - 10ppm-<- 2,4,5-TA - 20 ppm - 9/11/ 



2^ 



u 



10 .. 



Average Flesh Firmness (lbs.) 



1. 14.7 



2. 14.0 



3. 13.8 



4. 13.9 



Figure I. The influence of some stop-drop materials on the rate of 

 preharvest drop of Mcintosh apples. 



