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USE OF ETHEPHON TO PROMOTE COLOR AND RIPENING 

 OF APPLES IN MASSACHUSETTS 



W. J. Lord and D. W. Greene 



The use of ethephon on early maturing varieties and Mcintosh 

 to stimulate red color development, increase soluble solids (sugar 

 content) , and hasten fruit maturity is now a standard practice in 

 many orchards. However , ethephon must be used with caution . The 

 mis-use of ethephon or an unavoidable delay in the harvest of ethe- 

 phon-treated fruit could intensify our current problems of supply 

 management and poor fruit condition. The placement in marketing 

 channels of an excessive volume of ethephon- treated 'Mcintosh' apples 

 that must be sold quickly because of over-maturity could depress 

 prices . 



Successful Use of Ethephon 



Ethephon will not completely overcome conditions unfavorable 

 for development of red color. Ethephon, at 1/4 or 1/2 pint may 

 add 10 to 30% red color to 'Mcintosh' apples borne on the periphery 

 of the trees within 7 or 8 days after application. Ethephon at 

 1/4 pint may promote as much fruit color as a 1/2 pint and will 

 cause less fruit softening. 



Under conditions that are normally associated with poor fruit 

 color, such as high temperatures, wet and cloudy weather, excessive 

 vigor or dense trees, ethephon- treated fruit may not develop suffic- 

 ient red color (50% of the surface having red color typical of the 

 variety) within 7 or 8 days after application. Furthermore, on 

 both young and older trees, ethephon may not bring the fruit in the 

 interior of the tree up to a satisfactory level within 7 days after 

 treatment. When the fruit are allowed to remain longer on the tree, 

 however, the color difference becomes greater between the ethephon- 

 sprayed interior fruit and the non-sprayed interior fruit. It is 

 of interest to note that 11 days after an ethephon spray (1/2 pt/100 

 gals of water) in 1974, 66% of the interior fruit on 10-year-old 

 trees had typical red color and would have graded U.S. Extra Fancy. 

 On the other hand, none of the interior fruit on the check trees 

 would have graded U.S. Extra Fancy due to lack of sufficient red 

 color. 



By the time the ethephon fruits in the interior of most trees 

 obtain adequate color, they will probably be suitable only for juice 

 or immediate sale because of excessive loss of firmness. The pro- 

 blem of obtaining adequate color on the interior of large dense 

 trees can be corrected somewhat by pulling the water sprouts during 

 the summer and doing some light summer pruning. These procedures 

 should be followed by spot picking which will lighten the crop load 

 and permit better light penetration into the interior of the tree 

 before the application of an ethephon spray. 



