8 



Based on this study, it appears that in orchards where valsa 



canker is not troublesome, dormant pruning may be advantageous from 



the standpoint of more shoot growth and flower buds and higher yields. 



Where valsa canker is troublesome, it appears advisable not to delay 



pruning later than full bloom. 



********** 



THE USE OF PROMALIN TO ELONGATE DELICIOUS APPLES: 

 RESEARCH OBSERVATIONS AND SUGGESTIONS FOR USE IN 1980 



Duane W. Greene and William J. Lord 

 Department of Plant and Soil Sciences 



Promalin* has been used in orchards in Massachusetts for several 

 years to increase the length of Delicious apples. Increased use has 

 given us experience so that we may better and more safely use this 

 growth regulator. It is the purpose of this article to review our 

 research findings and update our recommendations for the use of Pro- 

 malin in 1980. 



Coverage . Last year ( Fruit Notes 44(3): 4-8) we showed that the 

 absorption and/or translocation of Promalin was quite limited. This 

 is supported by our 1979 data showing that when a 25 microliter drop- 

 let of Promalin was placed on the flower petals there was no increase 

 in the L/D ratio** of fruit at harvest (Table 1 below). 



Table 1. Effect of the site of Promalin application on the L/D ratio 

 of 'Richared Delicious' apples. 



Treatment" 

 (microliters ) 



1978 



L/D ratio 



1979 



1. Check 



2. Petals, 25^ 



3. Petals, 150 



4. Receptacle surface, 



5. In calyx end, 25 



6. Pedicel, 25 



7. Spur leaves, 250 



25 



93c" 



94c 



99b 



03a 



03a 



.91c 

 .91c 



1.03a 



1.04a 



.97b 



.90c 



50 ppm solution containing 0.05% X-77 applied at full bloom. All 

 blossom clusters reduced to one flower and then hand po llina ted with 

 'Early Mcintosh' pollen. 



A 25 microliter droplet was large enough to wet the receptacle and 

 pedicel surface with no runoff, 

 c 



Numbers in a column followed by a different letter are significantly 

 different at odds of 19 to 1. 



*Trade Name 



**Larger the L/D ratio, longer the fruit 

 have an L/D ratio of 1:00 or more. 



A "typey" Delicious will 



